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jack_sparrow

Firefly Carbon Foam Batteries…. the Poor Man’s Lithium???

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Traditional batteries will never go close to matching the attributes of Lithium. Ignoring True Costs/Kw and putting aside Life Cycle and Weight/Space constraints of say AGM batteries compared to Lithium, the cons of AGM’s are:

1. Low usable capacity of around 35% (or say 50 -75% SOC);
2. Slow recharge speed;
3. Low charging efficiency (having to put more back in than taken out); and
4. Regular recharge to 100% SOC (to limit sulphation to preserve battery capacity and life).

It is these four constraints that cause diesel poor long distance/remote cruisers and racers alike to ignore the cost and complexity and turn to Lithium if they have the means. Interestingly these constraints don’t impact on coastal sailboat cruisers and racers near as much and therefore they can survive quite happily without looking beyond traditional battery offerings. The sailboat market is small enough as it is without this division of interest making it an even smaller market for anyone contemplating producing alternative battery technology.

With this in mind I find the Firefly battery using Carbon Foam technology a very interesting development and worthy of close examination. It seems as though it could fill an ideal performance gap somewhere between AGM and Lithium. It’s appeal as a “drop in” alternative without requiring the “total system” requirements and corresponding installation skills demanded by Lithium also makes it a compelling alternative.

Here is their website which has lot of technical information. http://fireflyenergy.com/
Practical Sailor (Rod Collins) has just bench tested them with other AGM’s and a Lithium as a benchmark. You have to be a subscriber to access this. While positive they are awaiting more real life data to come to light before jumping in the deep end. http://www.practical-sailor.com/blog/Can-Carbon-Foam-Batteries-Meet-Hype-11694-1.html

Bruce Schwab of Ocean Planet who is the NA dealer. http://www.bruceschwab.com/advanced-energy-storage-systems/firefly-energys-oasis-group-31/

 

These guys at Firefly have done it tough to get to where they are today and should be applauded for the effort. If anyone out there is using Firefly batteries there are many of us here who would love to hear of your real life experience with this very interesting power storage product.

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I'm not sure I agree with your "slow recharge speed" verdict. I've got Lifeline AGMs and the limiting factor is really the shoreside battery charger and alternators. I don't think that going to lithium would really buy me much in terms of time to 100% charge. That said, I agree that the Fireflies are very interesting, particularly the depth of discharge performance. However, until the Group 31 form factor is a problem for me. Hopefully they'll have them in 4D form by the time I need to replace my house bank.

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IStream I agree AGM batteries will quickly take lots of current in Bulk charging and that is one advantage they have over flooded lead acid’s. However the limiting factor to get to 100% SOC is not charging source as you suggest, it is the "current limiting'" factor of AGM's. Putting aside charging source limits, it will take hours and hours to get an AGM to 100% State of Charge (SOC) irrespective of the current source. By comparison Lithium can take very large currents and charge extremely fast. Remember there are two things that contribute to all AGM’s including your Lifeline’s being slow to charge relative to Lithium.

Firstly AGM’s have a “very long current taper”. While they might quickly Bulk charge a large proportion to say 85%, once “current limiting” kicks in and Absorption voltage is attained it takes a far longer time to get that last 15% in. By comparison Lithium has a very “short current taper” and will get to 99% before any current limiting occurs, irrespective of charge size and even with small charge sources like solar and hydro.

The second thing that makes AGM’s slow to charge is it is necessary to regularly charge them to 100% SOC to limit sulphation and preserve capacity and maximise the Bulk charging stage. Operating at Partial State of Charge (PSOC) without returning to 100% SOC very quickly reduces the amount of time an AGM battery is capable of accepting Bulk charging and therefore significantly increases charging time even further. This starts to occur only after a couple of charging cycles. Lithium on the other hand has no problem working at PSOC for extended periods.

 

By comparison the Firefly Carbon Foam Battery appears to have similar “current limiting” characteristics of other AGM’s in terms of initial Bulk charging speed. However where it differs is it can successfully operate at PSOC for extended periods. In other words like Lithium the Firefly doesn’t have to be subjected to long and regular periods of charging at Absorption voltage to attain 100% SOC to stop it’s Bulk charging stage shrinking and to preserve capacity like other AGM’s. Therefore in practical terms the Firefly charges far more quickly than other AGM’s but not near as quickly as Lithium, and particularly having regard to available capacity.

 

I am with you on current form factor availability.

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Well put Capt. Sparrow. The Firefly can be used rather like lithium if you have enough capacity so that bouncing between roughly 80% and 20% SOC gives you a workable window. That is, you can discharge to practical voltage floor of say 11.7V, then recharge in one shot up to around 80% SOC. Or whenever the current limiting is down to the level that the charging system is getting inefficient fuel-wise. Of course this means that having that capacity makes the bank much heavier than Li, as the useable capacity % isn't as much as Li (actually it is, from a full charge, but not from the point of current limiting). But at least the Firefly can take such PSOC use without going belly-up as would any other AGM will with extended PSOC use. And at much lower cost than Li.

 

We are working on Firefly to eventually make other sizes....next up is a 4V L16 size for bigger banks, and eventually a golf cart size. But those will take a while...

 

Haji/Bruce

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I just emailed the local Seattle dealer.

 

Occasional 80% DoD and 100ah battery makes this a lighter option for me than traditional AGM. One of these could replace the two group 24 AGM batteries in my house bank, and are a lot simpler to integrate than switching to LFP (which I've also considered).

 

$425 is a pretty reasonable price. I've also considered switching to flooded GC2 batteries, but would need to move my house bank to the bow of the boat which would cost a few hundred in battery cables. A single G31 wouldn't have quite the same useful capacity, but would be a simple drop in.

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What's the challenge to "integrate" LFP batteries? If you have any decent charge regulation, LFP is pretty straight forward - at least as easy as AGM support. Adding a BMS isn't exactly rocket science, especially if using a complete solution like Genasun or Mastervolt - it's a small box and a few wires and a remote switch.

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Thanks Haji. Great to have someone very close to this technology who can provide authoritative commentary. It is a rainy day here so I thought I might have a rant. I apologise for the length.

 

It is rare if not non-existent for someone to invest resources into battery technology with the sailboat user close to the front of their mind, hence why I started this thread to raise that awareness. Being a lead acid battery Firefly is not suited for hybrid vehicle use and hence it has to secure markets elsewhere. By way of explanation hybrid vehicles require a very high rate of charge to accommodate braking as a charge source and discharge for propulsion that lead acids can’t fulfil.

 

Normally we sailboat users have to wait for the spin-offs from more mainstream applications for power storage, which while they often appear similar to sailboat use, most are not and some adaptation or education is required.

 

Without marine specific adaptation problems arise, which then flow on to the new battery technology being unfairly deemed deficient. I have outlined below some historical examples of this and largely because the new battery technology has been treated as a “drop in” replacement without any thought given to modifying charging sources or educating the user about operation. The DIY nature of sailboat users compared to other marine users exacerbates this problem.

 

The Gel Battery

 

The genesis to the Gel lead acid battery was demand around 45 years ago for a sealed low maintenance alternative to flooded lead acid. However they are very sensitive to charging voltage being kept within a very very tight range in relation to temperature otherwise they quickly fail. It is easy to visualise what happens when gel batteries are “dropped in” to unventilated sailboat engine rooms with alternator regulators and AC battery chargers remaining unchanged. As a result of this misuse Gel batteries unfairly got a very bad name in the marine industry and many users reverted back to flooded batteries.

 

They are still manufactured today on account of their superior cycle life compared to AGM’s, however their recharge constraints, cost and undeserved reputation is contributing to their gradual demise.

 

The AGM Battery

 

Absorbent Glass Matt (AGM) lead acid technology followed Gel’s and became popular in the early eighties due to the need for a sealed robust battery for aviation, light vehicles and Uninterrupted Power Supplies (UPS) to service new computing and off-grid applications. As usual the sailboat market was furthest from the mind of those who first commercially offered this technology, however the sailboat crowd quickly joined other marine users (power boats) and started “dropping” them in account of their many advantages and many treating them no different to flooded lead acid.

 

Thirty five years on I’m amazed at the ignorance which still surrounds the operation of AGM’s. I would like a dollar for everyone who said to me that their top of the line AGM’s were dead after a couple of years and they were going back to flooded lead acids for better performance at half the price. I blame manufactures who are great at extolling the superior recharge rate and deep discharge capacity of AGM’s compared to flooded lead acids but little else. They and a lot of unknowledgeable installers have failed to properly educate users that an AGM battery’s usable capacity is around one-third to half the rated capacity and they are sensitive to overcharging (but more tolerant than Gel) and heat. Little has been said about usable capacity reducing particularly if they are not regularly charged to 100% SOC and while they might offer a depth-of-discharge of 80% DoD (11.7v), regularly exceeding 50% DoD or <12.7V quickly kills them.

 

How many users of AGM’s are also talked into upgrading their charging system (beyond matching the regulator to the new battery) to take advantage of their superior recharge rate so they can get away with having the motor run for only an hour a day!! They then find there is little change in charging time when trying to hit 100% SOC on account the concept of “current limiting” kicking in around 80% SOC is alien to them. Hey presto sick of the charging time they then revert to charging to only 80% SOC or 12.5v and low and behold they find the fast “bulk” charging time is getting smaller and usable capacity is shrinking (due to irreversible “sulphation”). Little wonder after that nightmare that their response to anyone who asks is AGM’s are rubbish.

 

One savour for AGM’s particularly as sailboats have become larger and more energy hungry over the last 35 years has been the proliferation of marinas with access to shore power for AC smart chargers. For those on a mooring the wider use of solar panels to regularly bring AGM banks up to 100% SOC and maintain a float voltage when not being used, thus improving their capacity, rate of charge and life expectancy.

 

Lithium

 

Hybrid cars and the growth in off-grid power storage in the last 10 years has been the genesis to lithium batteries and their associated battery management systems becoming commercially available to sailboat users.

 

With the exception of boats with diesel-electric propulsion, sailboats don’t really need a lithium battery’s high very rate of charge (RoC) and discharge qualities essential for hybrid vehicles. Lithium is attractive to sailboats because of their usable capacity, extended operation during PSOC, weight/bulk to capacity, recharge time in relation to usable capacity and cycle life. Interestingly these are the same characteristics offered by the Firefly Carbon Foam battery, albeit at lesser levels.

 

The take-up of Lithium by sail boat users has been low largely due to cost and being scared off by stories of thermal instability, fires, the Boeing Dreamliner problem and alike. Providing a lithium battery pack is designed for the marine market including incorporating a robust built-in battery management system (i.e. Genesun, Victron, and others) battery damage should not be an issue. The exception is total failure when they are subject to over-discharging and over-charging. It is noted the type of lithium batteries that are the subject of adverse publicity utilise completely different materials and battery chemistry compared to those tailored to marine purposes.

 

Beware of Chinese imitations!

 

Lithium V Firefly

 

What this all means is that with Lithium and Firefly Carbon Foam (with lesser but still compelling performance), sailboat users will quickly grasp hold of the fact that on top of vastly improved performance, a battery banks physical size can be downsized to equal existing usable capacity, or capacity vastly improved by maintaining existing current physical size.

 

As mentioned by Haji usable capacity for the Firefly with 80% SOC is around 60% of rated capacity and rising to 80% at 100% SOC. This compares favourably to Lithium at around 80% of rated capacity at 100% SOC (doesn’t have “current limiting” kicking in so 80% SOC an irrelevant measure). However it can’t be forgotten that a Firefly can’t be operated indefinitely at PSOC, as unlike Lithium it has to be brought to 100% SOC intermittently to preserve capacity and maximise the fast “bulk” charging band. AGM’s by comparison the usable capacity is around only 30% of rated capacity rising to 50% capacity at 100% SOC, however it requires very regular charging to 100% SOC i.e. every few cycles, albeit capacity will reduce over time regardless.

 

Similarly Lithium and Firefly’s can sit unused for extended periods at PSOC without incurring irreversible damage. However I’m led to believe the discharge curve of Lithium is flatter and stronger than Firefly’s (and AGM’s) right down to 80% DoD and Lithium won’t suffer the same degree of voltage drop under heavy loads.

 

There is a key difference between the charging characteristics of the two technologies. For Lithium apart from total failure attached to charging and discharging extremes, battery charging current “capability” compared to actual current “availability” on a normal sailboat will be the “limiting factor”. In other words what will occur in practise is existing and unmodified charging sources will quickly overstress and fail if they are not swapped out for larger rated units on account of the prolonged high rate of charge (RoC) attached to Lithium. An alternator will be running at full capacity or in “bulk” mode for almost the entire charge duration, except for a small “absorption” charge at the very tail end i.e. after 99% SOC.

 

Your standard run of mill marine alternator and possibly even its belt assembly is simply not capable of regularly doing this without some form of current limitation. However that limitation defeats the purpose of having Lithium in the first place. Therefore unlike in the case of AGM’s, upgrading alternator capacity not only makes sense, it is mandatory. AC charging sources also must be large and be programmable to suit Lithium, and preferably have dedicated voltage sensing. It is now easy to see how the changeover cost to Lithium can be cost prohibitive as it is more than just the batteries alone. It is a dedicated total system approach involving a lot of $, £, €, ¥.

 

Firefly Carbon Foam batteries on the other hand by still experiencing “current limiting” constraints of lead acid and having similar albeit a slightly greater RoC compared to AGM’s, will more readily adapt to existing charging sources on most sailboats without modification. In other words “current limiting” kicking in at around 80% SOC will give the bog standard alternator a breather if it is being charged to 100% SOC. Furthermore unlike Lithium a Firefly battery will recover from either being over-charged or over-discharged.

 

Hence why I regard the Firefly Carbon Foam as the Poor Man’s Lithium Battery.

 

The Future

 

I don’t see much cost benefit flowing to sailboat users from such things things as the Telsa Powerwall as it is off-grid specific and domestic by design. I would not expect Telsa to reduce the capacity to suit marine use and marinise it, the market is just too small.

 

To the contrary we may find the costs of Lithium batteries could plateau shortly and not fall too much further as many expect. That is because production scale may be getting close to optimum and demand is approaching the limit of natural material sourcing constraints. The future demand for Lithium is an interesting landscape when you consider countries like India with a very small proportion of its population currently enjoying mains electricity intending to use off-grid means to assist electrification of the country without relying totally on coal fired power stations that have environmental issues. This is similar to how they approached communications by leap frogging copper wired networks and going straight to wireless. The owners of Firefly are from India, a coincidence, maybe not.

 

Lithium will experience exactly the same problems of its two predecessors above if it is treated as a “drop in” replacement by sailboat users without giving any thought to modifying charging sources and being properly educated on its operation. I can hear the call going up now….. “Lithium batteries are rubbish, they turn alternators to toast, wear out drive belts and totally fail for no apparent reason”. Up until now I suspect safety concerns as much as cost is curtailing the enthusiasm of many to jump on the Lithium wagon, however once Lithium batteries gain wider acceptance and DIY’s think they don’t have to rely upon expert advice and installation, the misguided claims are sure to surface.

 

I understand Firefly are looking sometime in the future at incorporating thinner panels/plates to increase charging and discharging capability, although I suspect it won’t be near as high as Lithium. That specification will auger well in particularly for the further development of diesel-electric propulsion units in sailboats. As Haji points out there will be additions to the form 31 factor. That will be well received, particularly those looking for substantial storage capacity.

 

To conclude it seems to me Firefly Carbon Foam batteries might well fare a lot better than their predecessors in the new battery technology appreciation stakes, after all it has taken only 35 years for a wider understanding of AGM’s to gain a foothold!!!

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What's the challenge to "integrate" LFP batteries? If you have any decent charge regulation, LFP is pretty straight forward - at least as easy as AGM support. Adding a BMS isn't exactly rocket science, especially if using a complete solution like Genasun or Mastervolt - it's a small box and a few wires and a remote switch.

The Genasun and Mastervolt options are very expensive. I was considering DIY LFP options by purchasing cells and a BMS directly.

 

Either way would also require me to replace my solar controllers (currently Genasun) and my alternator regulator. My shore power charger is already programmable for the correct charging voltages.

 

This makes the cheapest LFP option somewhere around $1400 for a 100ah battery. If the Firefly can offer similar DoD in not much more space and for one third of the price but without being lighter then that is worth it. My 5ksb isn't going to light up by saving 30lbs.

 

The local dealer told me that Firefly batteries are temporarily unavailable while the factory retools. This is disappointing as I need a new battery by mid July.

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Moonduster it would be wonderful if Lithium installations were Plug n Play and or comparable to dropping in AGM batteries but the reality is they aren’t. As I indicate in my post #8 above, for most sailboat users Lithium is not a DYI project.

 

By way of explanation the bare minimum requirements for a LiFePO4 Battery Management System (BMS) is to firstly protect the vessel AND secondly the battery investment. The first line of defence is the incorporation of integrated cell balancing. Reputable manufacturers and suppliers of marine Lithium products attend to this.

 

The second line of defence is far more complicated and consists of a project specific BMS design that can automatically:

 

i) Shut down the load where there is pending cell under voltage; and

 

ii) Shut down or reduce charging current in the case of imminent cell over voltage, high temperature or low temperature.

 

This requires connecting the BMS ideally up to a “Dual Positive Bus” (and possibly certain charging sources) and a series of relays to “separate” Charge sources from the Loads. Further complexity is added where there is multiple charging sources such as auxiliary engine alternator(s), solar, hydro and Shore/Genset AC chargers etc. High current sources in particular such as Alternators and AC chargers will have to be either acquired and or modified accordingly to accommodate Lithium. On top of that to maintain the good practise of separating Starting and House battery banks things like a decent Battery Monitoring System with multiple shunts is also required. This is no job for the faint hearted or inexperienced.

 

The above is pretty general but it provides an idea of what is required and identifies the true costs attached to a Lithium installation. The ability to “drop” Firefly Carbon Foam batteries into an existing lead acid system with only minor modification makes it an attractive alternative.

 

PS. Correction to Post #8, Heading - AGM Battery, End of 2nd Paragraph. Delete <12.7v and insert <12.1v

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And having separate charge/discharge bus design requires a pair of contactors, a little bit of room and a few extra battery-sized cables that are a few inches long. In the face of any good battery installation (sense wires, shunts, fusing, set points, etc.) is that really insurmountable additional complication? Really?

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And having separate charge/discharge bus design requires a pair of contactors, a little bit of room and a few extra battery-sized cables that are a few inches long. In the face of any good battery installation (sense wires, shunts, fusing, set points, etc.) is that really insurmountable additional complication? Really?

My scond sentence post #10 says...."As I indicate in my post #8 above, for MOST sailboat users Lithium is not a DYI project". I have not used the word or even suggested Lithium instal complications are "insurmountable" as you state.

 

Moonduster rest easy, you are clearly one of those DYI exceptions,

 

The comparative "poor man's" advantage over Lithium I don't want to see lost is, most DIY's CAN drop in Firefly Carbon Foam because they don't have to make wholesale changes to their existing lead acid charge and load setup and then they can go on to use and maintain it accordingly without any fear.

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I believe you're sorely mistaken and that your premise is misinformed.

 

Most installations don't really work at all. They have automotive-style alternator regulation and fixed voltage shore power chargers. Three-stage regulation is the exception, not the rule. Battery abuse is the norm and the typical experience with any battery system is quite poor.

 

If your goal is to convince someone to slap in a new battery technology ... I suppose I don't understand the benefit. If your goal is to help someone make their system reliable and cost effective, then I don't see how Carbon Foam (or AGM) would be a reasonable choice. If you're talking to the very small percentage of people who have a highly functional solution then in my experience, they know it's not a poor man's game and they probably don't need much help.

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I believe you're sorely mistaken and that your premise is misinformed.

 

Most installations don't really work at all. They have automotive-style alternator regulation and fixed voltage shore power chargers. Three-stage regulation is the exception, not the rule. Battery abuse is the norm and the typical experience with any battery system is quite poor.

 

If your goal is to convince someone to slap in a new battery technology ... I suppose I don't understand the benefit. If your goal is to help someone make their system reliable and cost effective, then I don't see how Carbon Foam (or AGM) would be a reasonable choice. If you're talking to the very small percentage of people who have a highly functional solution then in my experience, they know it's not a poor man's game and they probably don't need much help.

Clearly you can write but don't bother to read. Shut up before you hurt yourself.

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Yikes! Relax guys! Both of you know far more than the average Joe, and IMHO on actually on the same side(s) of the battery debate. I know for a fact that MD knows Li systems in great detail and has integrated them into the most advanced sailing machines imaginable. Installing any brand of Li is no big deal for him, so the dummy-proof properties of Firefly aren't really relevant to him.

 

Capt. Jack has a great understanding of Pb battery characteristics (yes, good old GEL batts are very under-rated!!) and their limitations. MD is right that CJ wouldn't have much trouble doing an Li system installation. However, CJ is just pointing out that the average Joe is not capable of figuring out an Li system install in a short time, and may not have the $ to hire someone who can. So for said avg. Joe who wants a simple solution without upgrading the existing charging system the Firefly is nice option.

 

Yes, the Firefly will get the same under-charging abuse that ruined poor Joe's previous AGM's, however at least the extended PSOC cycling life that is so often the reality of Pb battery life, won't ruin them. Actually the only way to ruin the FF's is to chronically over-charge them (>14.4V), however that is much less likely to happen on the average Joe's boat than chronic undercharging.

 

So...can't we all get along?

Haji

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Just to complicate things, I came across a vendor at IBEX last year that claimed to have a LiFEPo4 drop in replacement for LA batteries with no need to alter charging systems. Ummm... scary.

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I have just installed a lithium pack into a racing boat to replace old agms.

There seems to be very complicated systems around that are very expensive.

I have no clew about marine electrics but have taken out large agms stuck in a 200amp lithium winston battery pack which cost $1200. Added a low voltage cut out relay set at 11.8v to protect the lithium ($100) and a cell balancer called a relative $40.00.

Took a couple of hours to wire it all up.

This removed 50kg out of the boat

I am sure the alternator works harder because the lithium sucks up the charge but you do not have to run the engine for as long.

The original battery charger seems to work fine as well although it works hard too.

There could be other problems but it all seems very simple to me.

There is a lot of smoke and mirrors out there from battery manufacturers.

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Just to complicate things, I came across a vendor at IBEX last year that claimed to have a LiFEPo4 drop in replacement for LA batteries with no need to alter charging systems. Ummm... scary.

Did they happen to be also selling asbestos kids toys??

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I have just installed a lithium pack into a racing boat to replace old agms.

There seems to be very complicated systems around that are very expensive.

I have no clew about marine electrics but have taken out large agms stuck in a 200amp lithium winston battery pack which cost $1200. Added a low voltage cut out relay set at 11.8v to protect the lithium ($100) and a cell balancer called a relative $40.00.

Took a couple of hours to wire it all up.

This removed 50kg out of the boat

I am sure the alternator works harder because the lithium sucks up the charge but you do not have to run the engine for as long.

The original battery charger seems to work fine as well although it works hard too.

There could be other problems but it all seems very simple to me.

There is a lot of smoke and mirrors out there from battery manufacturers.

I agree battery smokin is not good... any chance you could post a simple diagram showing charge and load circuits to the battery??? I'm sure Moonduster could offer a quick boat saving appraisal.

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Just to complicate things, I came across a vendor at IBEX last year that claimed to have a LiFEPo4 drop in replacement for LA batteries with no need to alter charging systems. Ummm... scary.

Did they happen to be also selling asbestos kids toys??

Binkys designed to meet the 2.5 minute fire test... genius!

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I have just installed a lithium pack into a racing boat to replace old agms.

There seems to be very complicated systems around that are very expensive.

I have no clew about marine electrics but have taken out large agms stuck in a 200amp lithium winston battery pack which cost $1200. Added a low voltage cut out relay set at 11.8v to protect the lithium ($100) and a cell balancer called a relative $40.00.

Took a couple of hours to wire it all up.

This removed 50kg out of the boat

I am sure the alternator works harder because the lithium sucks up the charge but you do not have to run the engine for as long.

The original battery charger seems to work fine as well although it works hard too.

There could be other problems but it all seems very simple to me.

There is a lot of smoke and mirrors out there from battery manufacturers.

 

What is the charging voltage of your alternator? How are you making sure that you aren't overcharging the LFP pack? $1200 is an expensive battery to potentially toast.

 

I already have 3-stage chargers for all three charging sources (solar, alternator, shore power) and 2 of those 3 aren't lithium compatible. I understand making my system LFP compatible and what it takes to do it DIY. The carbon foam is a much cheaper option with a little weight penalty, which is what makes it interesting.

 

I have one on order and hope it arrives in time for my summer cruising. The local distributor told me that demand is high and that the factory is doing some retooling.

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I have just installed a lithium pack into a racing boat to replace old agms.

There seems to be very complicated systems around that are very expensive.

I have no clew about marine electrics but have taken out large agms stuck in a 200amp lithium winston battery pack which cost $1200. Added a low voltage cut out relay set at 11.8v to protect the lithium ($100) and a cell balancer called a relative $40.00.

Took a couple of hours to wire it all up.

This removed 50kg out of the boat

I am sure the alternator works harder because the lithium sucks up the charge but you do not have to run the engine for as long.

The original battery charger seems to work fine as well although it works hard too.

There could be other problems but it all seems very simple to me.

There is a lot of smoke and mirrors out there from battery manufacturers.

 

What is the charging voltage of your alternator? How are you making sure that you aren't overcharging the LFP pack? $1200 is an expensive battery to potentially toast.

 

I already have 3-stage chargers for all three charging sources (solar, alternator, shore power) and 2 of those 3 aren't lithium compatible. I understand making my system LFP compatible and what it takes to do it DIY. The carbon foam is a much cheaper option with a little weight penalty, which is what makes it interesting.

 

I have one on order and hope it arrives in time for my summer cruising. The local distributor told me that demand is high and that the factory is doing some retooling.

 

alternator charge is set at 14.8v but the low voltage cut out also has a high voltage cut out of 15.6v just in case.

I could be missing something but the system seems to work.

Also the voltage cut outs need to be solid state variety to reduce current draw down.

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14.8 volts is a crazy high charging voltage for LFP batteries from everything that I've read.

 

I suggest reading the "cons" section here:

http://www.pbase.com/mainecruising/lifepo4_on_boats

 

Page 3 talks about how the alternator should be configured:

http://www.pbase.com/mainecruising/lifepo4_on_boats&page=3

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I agree, that seems really high as far as voltage goes. I have a 300Ah LiFEPO4 on my last boat for a few years before I sold it, but at the end of 2 years installed, it still had pretty close to it's initial capacity.

 

I am pretty sure I have the voltages for all my charge sources (well at least my solar and my alternator as I was unplugged most of the time) set at about 13.9, with the float disabled on all of them. My 220V shore charger, which was only a small 20A one for keeping the batteries topped off while at dock wasn't programmable, but I used the GEL setting which was 14.0 V, but still had a float turned on, so that wasn't perfect, but was close.

 

One article I have read as per 'lithium' batteries since I have been back was here:

 

http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/

 

This is someone with a similar system, but in a RV setting, but has had poor luck with the cycle life and has been told that the LiFePO4 batteries really don't like high temps very much. Now I think his situation is a little worse than a boat since we are a big floating heat sink, and in my care the batteries were NOT in the engine compartment, but that is interesting none-the-less.

 

Our current boat, which is being used as a live-aboard (well soon, we are not moved in yet) is just using 6V deep cycles. I will probably install something higher-tech before we set out for cruising again, but that is not for a few years so it didn't make sense to buy fancy batteries while primarily sitting at the dock...

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Article on pbase.com one of the best out there regarding Lithium for sailboat applications. Thanks Alex W.

 

Remember the Firefly can be used much like Lithium by bouncing between 80% and 20% SOC (with only the occasional 100% SOC to preserve capacity and charging time). An AGM simply CANNOT be used like this without suffering reduced performance and premature death.

 

The comparative high expense of Lithium is the battery cost PLUS properly installing it PLUS feeding it with a Lithium specific charging source(s). The risks attached to not doing that are at best goodbye expensive batteries or at worst goodbye boat and or serious injury. On the other hand Firefly's and AGM's share a much lower installation cost/complexity and risk profile.

 

I have attached a typical "dual positive bus" diagram for a typical Lithium battery setup to illustrate the ADDITIONAL equipment and installation requirements of Lithium compared to Firefly's and all lead acids. I forget where I sourced it, so I apologise for not attributing a credit.

Dual-Buss-Diagram.pdf

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I'm not sure I agree with your "slow recharge speed" verdict. I've got Lifeline AGMs and the limiting factor is really the shoreside battery charger and alternators. I don't think that going to lithium would really buy me much in terms of time to 100% charge. That said, I agree that the Fireflies are very interesting, particularly the depth of discharge performance. However, until the Group 31 form factor is a problem for me. Hopefully they'll have them in 4D form by the time I need to replace my house bank.

If you have really small little charge sources, compared to the bank size, such as charging at 0.05C, (5A per 100Ah's) then there would only be a small improvement. However if you charge AGM's at .25C - .40C then the improvements are rather startling..

 

On Friday we had no wind in the morning so we opted to motor a bit.. We were down -224 Ah's and in two hours the bank was 100% full and the alternator was turned off....... You simply can't charge an AGM to 100% SOC in less than 2 hours unless you stared at 99% SOC...... Course with LFP we never need to get to 100% SOC. The only reason I did is because I wanted to go until today with no engine charging, with some fairly eggregiious use of the bank....

 

In order to get an AGM to full using return amps @ absorption voltage (versus return capacity such as 110% or 120% of removed Ah's) on an AGM the return amps will range from between 0.5% and 0.3% at absorption voltage, or 0.5A to 0.3A for every 100Ah's of capacity while at absorption voltage. This can take 8-10 hours and sadly most regulators and chargers will have prematurely dropped to float before 0.5% to 0.3% at absorption voltage even occurs. In the recent testing I did this took hours, and hours and hours to get to 100% SOC, even when starting with a very high charge rate... Once the batteries attained absorption voltage the time to 0.5% or 0.3% is tediously long...

 

This is where the Firefly AGM can shine because unlike traditional AGM batteries its need to get back to 100% SOC, is far less than that of traditional AGM's, so you can cycle between 20% SOC and 80% SOC and just occasionally do a 100% cycle. This type of PSOC abuse is very damaging to a traditional AGM...

 

Sadly what is lacking in the battery industry is honesty. They mislead us about nearly everything. The BCI really needs to define a PSOC test, and all deep cycle battery makers should be required to test to a PSOC standard. In a perfect world all "Deep Cycle" labeled batteries would carry a PSOC tolerance rating just like an Ah capacity or reserve minutes or CCA or MCA spec.

 

Course this will never happen...... :angry:

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That Dual Buss diagram was created by Rob Warren (aka "Yoda") at Coastal Climate Control in MD. Who coincidentally is our SE Solbian solar distributor AND also a dealer for both Firefly and Genasun GLi. He knows his stuff, so we steal his diagrams often....;-)

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Remember the Firefly can be used much like Lithium by bouncing between 80% and 20% SOC (with only the occasional 100% SOC to preserve capacity and charging time). An AGM simply CANNOT be used like this without suffering reduced performance and premature death.

 

 

 

While the Firefly can certainly be used for extended periods between full recharges it is important to remember that the usable capacity, between full recharges, is still "walking down" due to sulfation build up. An LFP battery does not "walk down" during PSOC use thus using an Ah counter to track Ah capacity is significnatly easier. An Ah counter simply can not track the walk down and is yet another reason why they are often so inaccurate..

 

Quote = Nigel Calder

 

"After discharging the 24v series/parallel Firefly pack to 38% SoC last August I left the batteries disconnected all winter over (over 8 months). When I got here I did a normal recharge with the 4 batteries in 24v series/parallel mode. I held the absorption voltage overnight (i.e. no specialized voltage/current; just an extended timer on the absorption for a mild overcharge without equalization voltages), ran the batteries in boat use for several hours with a float charge, then did a C20 capacity test. I got right at 110 Ah per block at the C20 rate, so this looks really good. I recharged with a voltage limit of 28.8v (14.4v/block) and a current limit of 0.25C. The 4 batteries maintained an amazingly consistent voltage on discharge and recharge. All-in-all, this is very positive.

 

Nigel"

 

He actually left his bank of Firefly's at 38% SOC for over 8 months, and they fully recovered! This would be a death sentance for just about any other lead acid battery I know of, because I see it happen in weeks, not months.........

 

The differnce between the Firefly and other AGM batteries is that the sulfation is reconvertable with just a couple of deep discharges and full recharge cycles where there is permanant loss of capacity in standard AGM's when you do this. The other AGM's in the PS testing lost from 7% to 30% of their Ah capacity under identical testing.

 

On PSOC cycle #1 (labeled column 3) we can see that 49.7 Ah's of usable capacity was available from a 1 hour recharge at .46C. Over 30 cycles like this there was a loss of 14.6 Ah's by PSOC cycle #20 (labeled as #23). So the battery does sulfate, it is still lead acid, but the important aspect is at #35 where the battery fully recovered by the second deep cycle with full recharge. This required no equalization or higher voltage, just a couple of deep discharges with 100% recharge. Walking down is normal in lead acid batteries that are PSOC cycled. Losing capacity from PSOC cycing is also normal for most all lead acid batteries when PSOC cycled. That the Firefly recovers fully from this abuse is really pretty exciting.

 

While the Practical Sailor article is a good comparison between brands I think Nigel's recent testimony on his Firefly's is rather astounding!

 

 

 

ff-testing-graph1.jpg

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Battery applications in sailboats, particularly long distance cruisers and racers really is a “niche-niche” market. Therefore Main Sail like many readers I found your battery comparative test in Practical Sailor a “must read” as it was the first independent appraisal of Firefly’s I had come across. It was also the genesis to me starting this thread.

 

As for Nigel Calder’s real life tests, they probably put the ability of Firefly’s to “reverse” the “sulphation” effects of PSOC use beyond all doubt.

Main Sail are you able quantify and or make some comment on the comparative recharging characteristics between Firefly’s, traditional AGMs and Lithium? I note you charged each battery for one (1) hour at the same rate (0.46C) for 30 PSOC cycles and recorded that data. For example to support a re-test, you indicated one battery’s acceptance rate (Deca) dropped sharply after just 40 minutes of charging or after the one-hour charge cycle, this battery was only accepting 11.3 amps and not the full 48 amps it accepted at the beginning.

Can you share other PSCOC charging data as “PSOC recharge times” between Firefly’s and other AGM’s is not available and it is potentially the biggest difference between Firefly’s and Lithium?

Main Sail thank you again for the valuable commentary.

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Battery applications in sailboats, particularly long distance cruisers and racers really is a “niche-niche” market. Therefore Main Sail like many readers I found your battery comparative test in Practical Sailor a “must read” as it was the first independent appraisal of Firefly’s I had come across. It was also the genesis to me starting this thread.

 

As for Nigel Calder’s real life tests, they probably put the ability of Firefly’s to “reverse” the “sulphation” effects of PSOC use beyond all doubt.

 

Main Sail are you able quantify and or make some comment on the comparative recharging characteristics between Firefly’s, traditional AGMs and Lithium? I note you charged each battery for one (1) hour at the same rate (0.46C) for 30 PSOC cycles and recorded that data. For example to support a re-test, you indicated one battery’s acceptance rate (Deca) dropped sharply after just 40 minutes of charging or after the one-hour charge cycle, this battery was only accepting 11.3 amps and not the full 48 amps it accepted at the beginning.

 

Can you share other PSCOC charging data as “PSOC recharge times” between Firefly’s and other AGM’s is not available and it is potentially the biggest difference between Firefly’s and Lithium?

 

Main Sail thank you again for the valuable commentary.

 

 

There really was no comparison during the PSOC testing between the AGM and the LFP with regard to "walk down". All the AGM batteries looked similar to the Deka (all within a few amps) after the PSOC walk down. You just can't fit all that data into one article.

 

The LFP battery never "walked down" and thus never attained target voltage and it took the full current for all 30 cycles.. All the AGM's, beyond a few cycles, attained absorption voltage and the bulk charge duration got shorter and shorter as capacity "walked down" due to sulfation. The high acceptance rate duration gets shorter and shorter the more you PSOC. The overall charge efficiency also went down slightly and attaining a full recharge took longer at the end of the test than at the beginning.

 

They real jewell in this test is what happend at the end. All the AGM's, with the exception of the Firefly, suffered permanently reduced Ah capacity. During PSOC they all performed similarly. The end is where the differnces were.

 

I can't publish specific data because it may be used for subsequent articles..

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Maine Sail thanks for that. I appreciate that all data couldn’t be splashed out in just one article and I certainly don’t want to cut PC’s grass in terms of future publications. However I do have an observation about your tests.

 

When to Recharge Firefly’s to 100% SOC?

 

Obviously Firefly’s like all AGM’s start to “walk down” in varying degrees after the first PSOC use cycle. However it appears the Firefly possibly exhibits quite different charge acceptance rate characteristics compared to the other AGM’s. Your tests indicated all the AGM’s demonstrated for the most part a uniform weakening of capacity or “walking down” between day 1 and day 30, but there were some significant differences early and mid-test up until around day 16.

 

Remembering these batteries experienced a flogging (11.7v or 75% DoD and then a partial recharge of only 1 hour starting at 0.46C over 30 daily cycles), the Firefly chart you have posted above indicates it dropped 18% or nearly 9 Ah up to day 7 then remarkably it plateaued out over the next 10 days losing no more capacity at all! The premium AGM’s Lifeline and Odyssey on the other hand dropped more slowly by 14% and 6% respectively up to day 7, but then experienced an overall drop of 26% (12 Ah) and 22% (10 Ah) 10 days later at the end of day 16. Interestingly Firefly and Lifeline both experienced the worst overall drop of around 14Ah at the end of 30 PSOC cycles (before the 100% SoC restoration cycle).

 

The above points to me that there is possibly a charging sweet spot for Firefly’s. For instance for a Firefly powered long distance, fuel poor sailboater who is discharging to around 20% SoC, partially charging and surviving happily with the PSOC capacity generated, then maybe their wasting valuable fuel doing a recharge to 100% SOC any earlier than every two weeks!!

 

Having said that, longer term that sort of use would come at expense of duty cycle. AGM’s on the other hand simply do not survive that level of punishment.

 

Lithium Instalation Cost and Heat

 

It seems some capacity fade occurs in Lithium over time when regularly cycled. This might be on account of trapped ions and internal corrosion blah blah, but possibly the greatest culprit is heat? I don't know.

 

While heat is the common enemy of batteries of all constructions and in varying degrees, maybe anyone making a comparative cost assessment between Lithium and Firefly’s should also factor in providing a well ventilated space for Lithium as “must do”, if only to preserve with certainty its higher capital expense. However that quite often is easier said than done in modern shallow bilged sailboats, so some existing storage capacity may have to sacrificed to accommodate Lithium. The upside is the physical size and weight of Lithium makes that sacrifice easier to digest. I have not heard of it, but maybe “forced ventilation” for some sailboat lithium installations is a good idea?

 

Conversely most existing AGM battery locations in sailboats, like their charging sources are more than suitable for Firefly’s as a “drop in” replacement.

 

Can't wait to hear more about real life Firefly experiences.

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Some comments:

 

Li:

We are finding that calendar life is shortened not so much by cycling, but also that simply sitting around fully charged for long periods can slowly reduce capacity. So for calendar life it's better actually use/cycle them, or if not in use to leave them sitting around 50-60% SOC.

 

Firefly:

The proverbial periodic 100% charge simply may not be necessary. Or at least not very often. The fact that they can recover full capacity (or more!) after a month of PSOC use suggests that it just doesn't matter much to them. We were told by the lead FF engineer that in some military testing they discharged them to 0V(!) with a resister across the terminals, let them sit for a month, then did a few full cycles to see how much they could recover. Amazingly, they actually GAINED capacity. It seems that fully sulfating the carbon foam plates actually conditions them somehow, so that when charged back up the sulfation comes off and the plates are actually more reactive than before.

 

If he was a marketing guy (instead of an engineer), he would have made a big deal about this years ago! It blows my mind that the very treatment that would totally ruin another AGM, actually made the FF work better. Truly amazing.

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Maine Sail thanks for that. I appreciate that all data couldn’t be splashed out in just one article and I certainly don’t want to cut PC’s grass in terms of future publications. However I do have an observation about your tests.

 

When to Recharge Firefly’s to 100% SOC?

 

Obviously Firefly’s like all AGM’s start to “walk down” in varying degrees after the first PSOC use cycle. However it appears the Firefly possibly exhibits quite different charge acceptance rate characteristics compared to the other AGM’s. Your tests indicated all the AGM’s demonstrated for the most part a uniform weakening of capacity or “walking down” between day 1 and day 30, but there were some significant differences early and mid-test up until around day 16.

 

Remembering these batteries experienced a flogging (11.7v or 75% DoD and then a partial recharge of only 1 hour starting at 0.46C over 30 daily cycles), the Firefly chart you have posted above indicates it dropped 18% or nearly 9 Ah up to day 7 then remarkably it plateaued out over the next 10 days losing no more capacity at all! The premium AGM’s Lifeline and Odyssey on the other hand dropped more slowly by 14% and 6% respectively up to day 7, but then experienced an overall drop of 26% (12 Ah) and 22% (10 Ah) 10 days later at the end of day 16. Interestingly Firefly and Lifeline both experienced the worst overall drop of around 14Ah at the end of 30 PSOC cycles (before the 100% SoC restoration cycle).

 

The above points to me that there is possibly a charging sweet spot for Firefly’s. For instance for a Firefly powered long distance, fuel poor sailboater who is discharging to around 20% SoC, partially charging and surviving happily with the PSOC capacity generated, then maybe their wasting valuable fuel doing a recharge to 100% SOC any earlier than every two weeks!!

 

Having said that, longer term that sort of use would come at expense of duty cycle. AGM’s on the other hand simply do not survive that level of punishment.

 

Lithium Instalation Cost and Heat

 

It seems some capacity fade occurs in Lithium over time when regularly cycled. This might be on account of trapped ions and internal corrosion blah blah, but possibly the greatest culprit is heat? I don't know.

 

While heat is the common enemy of batteries of all constructions and in varying degrees, maybe anyone making a comparative cost assessment between Lithium and Firefly’s should also factor in providing a well ventilated space for Lithium as “must do”, if only to preserve with certainty its higher capital expense. However that quite often is easier said than done in modern shallow bilged sailboats, so some existing storage capacity may have to sacrificed to accommodate Lithium. The upside is the physical size and weight of Lithium makes that sacrifice easier to digest. I have not heard of it, but maybe “forced ventilation” for some sailboat lithium installations is a good idea?

 

Conversely most existing AGM battery locations in sailboats, like their charging sources are more than suitable for Firefly’s as a “drop in” replacement.

 

Can't wait to hear more about real life Firefly experiences.

Considering some of the tight temperature constraints of Li-Ion, I'm surprised there hasn't been more discussion regarding active ventilation. Aus-NZ standards are the only requirements I have seen that require active ventilation for battery systems (regardless of chemestry) who address it more like gasoline engine spaces. How about from the manufacturers, are they requiring it?

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Just to be clear, we are NOT talking Lithium-Ion batteries here but rather LiFePO4 (or some very similar chemistries that all add yttrium) They both have Lithium in them, but the overall battery chemistries, energy density, and more importantly safety factors are quite different.

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LiFePO4 like any battery is only unsafe if not properly installed. Probably safer standalone than lead acid constructions.

 

I don't know if excessive heat permanently impacts upon LiFeP04's Ah capacity and if so enough to warrant better than AGM standard ventilation?

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That is pretty amazing stuff Haji. It is a shame these guys didn't have enough capital to get these on to the commercial market 5 - 10 years ago. Current supply constraints are not exactly making it easy for us sailboaters to jump in and give FF's a try either.

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It appears from this thread that the followings type of batteries suit the following types of yachts:

 

1. Racing boats- High budget end, ie light displacement types - Use LiFeP04 (light weight to keep the boat light) with the charging system to suit, for the offshore racing look at 2 x house batteries with it's own BMS for redundancy, high output alternator with smart regulator to provide key parameter adjustments, ie current limit, high voltage limits etc.

 

2. Racing Boats - lower budget end and Cruiser/Racers - Use the Firefly batteries (Weight may not be a priority) - little changes to the charging system and more useable capacity compared to AGM. May consider smart regulator to assist with charging and protect batteries.

 

3. Cruising Boats - Stay with AGM (weight not an issue just uses space) or replace with Firefly (good for space limitations)

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My point is that Lithium-Ion batterys are not an inherently stable chemistry. Read all the articles about exploding iphones and the issues boeing had with the 787. They have the best energy density of mainstream batteries, but really need to be handled with gloves on to be safe, and honestly I am not sure if I would put them on a boat...

 

LiFePO4 are slightly lower energy density, but are a much more stable chemistry. I have seen ones that have been abused in testing or electrical vehicles where the cases were melted, but that was it, and I know at least one manufacturer shot one with a gun and it didn't start fire.

 

As for the whole temperature affects on them, I have only read that one article, and like Maine Sail says, the manufacturers are VERY cagey about this kind of information. My old pack did spend two years in the south pacific and seemed healthy when I sold the boat, so my limited personal experiance doesn't bear that out, but I never had temps over say 90 in the boat, and I think the guy i the RV was in the southwest and his batteries were near his engine compartment, so I could easily see temps MUCH higher there.

 

And as to the list of batteries from Chucky, don't forget good old deep cycle wet cells. They can be equalized to somewhat reduce sulphation if abused, are the cheapest of the bunch by far and all of the lead batteries have pretty similar energy density. You do have to watch them and water them occasionally, but if your chargers are working correctly, that doesn't need to be that often. They are also available everywhere in the world, so when a batter fails and you are in Tonga, you can actually find one

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It appears from this thread that the followings type of batteries suit the following types of yachts:

 

1. Racing boats- High budget end, ie light displacement types - Use LiFeP04 (light weight to keep the boat light) with the charging system to suit, for the offshore racing look at 2 x house batteries with it's own BMS for redundancy, high output alternator with smart regulator to provide key parameter adjustments, ie current limit, high voltage limits etc.

 

2. Racing Boats - lower budget end and Cruiser/Racers - Use the Firefly batteries (Weight may not be a priority) - little changes to the charging system and more useable capacity compared to AGM. May consider smart regulator to assist with charging and protect batteries.

 

3. Cruising Boats - Stay with AGM (weight not an issue just uses space) or replace with Firefly (good for space limitations)

Chucky I think you can apply application for each battery type a little more differently than the traditional “boat type” approach you have adopted.

 

While a high capacity to low weight ratio is certainly important to race boats and less so to cruisers, I think “charging capability” in relation to the type of voyaging being done and battery load is the main battery selection tool. Here are some examples:

 

A coastal racer whose longest offshore race is say 600 mile a few times a year at best is going to be extremely happy with Firefly’s and maybe even AGM’s without going to the overall expense of LiFeP04. The exception would be say a race boat incorporating the additional load of electro-hydraulics. Unsealed flooded lead acids are not permitted on race boats.

 

However a trans ocean or round the world fully crewed racer that has regular stopovers like the VOR, will have to opt for LiFeP04 (particularly with the loads generated by media equipment) and while fuel is not an overriding problem between stopovers for their relatively small auxiliary engines, they will have to employ an integrated flywheel generator as a alternator alone won’t generate enough current that LiFeP04’s are capable of accepting in a short period of time.The same applies to long distance short-handed racers where the largest load is the auto-pilot.

 

At the other end of the spectrum a race boat in a non-stop round the world race, LiFeP04 is the only choice because fuel is the constraint and to the extent the principle charging source is hydro and the like.

 

Similarly for cruisers a long distance sail boater that is fuel poor and spending time in remote locations where fuel quality and availability is a constraint, will jump at Firefly’s and budget permitting LiFeP04. They will probably have at least two(2) and more like three(3) generating sources, namely auxiliary, solar, wind or hydro. It is hard seeing a serious remote cruiser opt for AGM’s over Firefly’s.

 

On the other hand a coastal cruiser (operating in other than remote locations) while having LiFeP04 or Flyfly’s would be nice, can quite happily survive on AGM’s or flooded lead acid’s, particularly if they spend a lot of time on shore power, or if on a mooring have solar to keep AGM’s topped up to 100% SOC between cruises. That said a cruiser with even moderate loads is probably going to opt for Firefly's over other lead acids.

 

If Firefly and LiFeP04 energy storage systems make inroads into the sailboat market that they deserve, then I suspect many people will start treating AGM’s and flooded lead acid as the cheap but disposable alternative.

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Just to be clear, we are NOT talking Lithium-Ion batteries here but rather LiFePO4 (or some very similar chemistries that all add yttrium) They both have Lithium in them, but the overall battery chemistries, energy density, and more importantly safety factors are quite different.

 

Sorry for the slow response… When given the choice to sail or sit in front of my PC and post, my decision is easy. I’ll confess that the majority of my hands-on battery experience comes from testing 9v batteries with my tongue. So I’m in constant learning mode.

 

My understanding of the term Lithium Ion is that it is descriptive of a family of batteries using organic electrolytes (lithium salt) including:

  • Lithium iron phosphate (LiFePo4) (Mastervolt, Gensun, more…),
  • Lithium Nickel Manganese Cobalt Oxide (LiNMC) (Torqueedo)
  • Lithium Manganese Oxide (LiMn2O4) (??).

The alternative family of batteries is that of inorganic electrolytes (Lithium Polymer and metals) which are not being used in the marine industry (as far as I know).

 

In terms of my temperature comment, many of the specs I see for temperature relate to storage temps or discharge temps which certainly promote a wide spectrum (-4 to 140F is common). But it gets narrower with charging temps especially at high C rates. Below freezing is a big no-no because of crystals that form in the electrolyte. Above 113F is not recommended, but I am unclear on what happens at various C rates in excess of 113F. I think the automotive companies are using liquid cell cooling to offset the temperature range, but I haven’t seen that in the marine industry. But what’s the average temp of a battery compartment on a boat in Tampa this time of year?

 

Am I off base with either of these?

 

 

 

A little lite reading:

Proboatbuilder, June 2014, In the Buffer Zone, Nigel Calder (sorry no link, free subscription for industry folks tho)

http://batteryuniversity.com/learn/article/types_of_lithium_ion

http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures

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Thanks mtn_matt. I couldn't manage to navigate a way to getting a paid digital download of the Calder article, however I'm sure it is informative.

 

The difficulty I find getting authoritative information on Lithium and even more so Firefly is not just their relative recent availability but energy storage in sailboats being the cottage of all cottage industries compared to auto industry etc. Large scale white-boat manufactures like Beneteau etc don’t provide any guidance and I suspect will be very late adoptees of anything beyond AGM’s, except as a high priced option.

 

If it were not for the analysis being done by people like Maine Sail, Calder and alike and on top of that the work invested in energy solutions for long distance racers like Haji, we wouldn’t know very much.

 

The closest allied market is probably the RV market and in the US in particular. If capacity shrinkage for Lithium is an issue for some RV users it will probably be very difficult to pinpoint on account of the diversity of use and DIY installations. The culprit could be anything such as heat/battery location or say simply from extended periods sitting on a float voltage when in a RV park connected happily up to mains power? Whatever the cause I get the feeling it should be less of a problem in sailboats with professional installs.

 

As for safety whilst I know there have been thermal runway fires connected with unprofessional lithium-iron-phosphate (LiFePO4) installations, at least marine users don’t have to build fireproof battery boxes like Boeing has to contain the far more volatile and energy dense Lithium-cobalt chemistry it uses. I don’t like the sound of that remedy!!!!!!

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As for safety whilst I know there have been thermal runway fires connected with unprofessional lithium-iron-phosphate (LiFePO4) installations

Please cite. I don't know of any fires associated with thermal runaway in LFP.

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As for safety whilst I know there have been thermal runway fires connected with unprofessional lithium-iron-phosphate (LiFePO4) installations

Please cite. I don't know of any fires associated with thermal runaway in LFP.

Fortunately not widespread. Unfortunately most are anecdotal for a number of reasons but mainly boat fires with no injury are not afforded proper investigation, insurers don't seem to care and don't openly publish information if they do. Culprit of fire on Titan a RP 75 was lithium battery and less anecdotal as it occurred during Antigua RW.

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Was there any type of investigation into the RP 75 fire as to why the Lithium battery caused the fire? Did the RP75 have an adequate BMS installed.

 

Given the increasing number of yachts being fitted with LFP battery systems, there does not appear to be any fires/explosions reported that I am aware of?

 

Lithium batteries are used extensively in other applications such as IPhones, hybrid cars, hand power tools etc and we do not have fires with these devices that I am aware of?

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I don't have knowledge of any formal investigation into the RP75 fire, however with no injury and in a place like Antigua that is not unexpected. I recall a lithium battery fire on the large multi PlayStation but don't have any details.

 

Boat fires caused by lithium battery installations prompted the American Boat & Yacht Council (ABYC) to draft a technical paper on their use. That said the take up by boat owners is still very small so I suspect the number of instances of fire that prompted that paper was not large.

 

The only formal report I have read was that into the Vestus grounding last November during the VOR and involving a Mastervolt LFP setup. On page 59 it states as follows:

 

"LFP Batteries

 

247. The only point regarding equipment that is considered necessary to raise in this report concerns the LFP battery(s) catching on fire. The LFP batteries are reported to have started smoking shortly before abandoning the yacht. This is believed to be as a result of their exposure or submersion in salt water. This did raise a concern of fire and was one of the factors that influenced the decision to abandon the yacht.

 

248. When retrieving gear from the boat, at least one battery continued to smoke quite profusely and was left on a beach as it was considered dangerous. When the crew returned sometime later there was burnt remains and the battery had self-destructed. This is beyond the expertise available to the report team but it is considered significant and worthy of further investigation.

 

249. The report team considers that VOR should review LFP batteries and the risk of fire when in contact or submersed in salt water".

 

The reporting of the small number of lithium battery fires in boats seems to be restricted to those participating in an event (like VOR above) or the boat and or boat owner/operator happens to be famous/infamous.

 

Chucky suggest you Google "lithium battery fires" if your not aware of fires in lithium powered domestic devices.

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I am no expert, but isn't "smoking" iron phosphate different than the kind of fires you hear about with the cobalt ones. I thought it was the gasses venting. I had that happen to the LiFePO4 battery on my boat. Scared the crap out of me, but there was no melting or fire. I junked them and went with AGM until there are more people who understand how to work with them.

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Wow... I had not read that report about the Vestas. All the various technologies that we use commonly today have gone through technological hurdles like this, so I think its only a matter of time before these types of issues are nil. Right now, I think the only true concern I have regarding LFP installations is that there is no extinguishing agent for that type of fire. The battery industry generally says, keep it as cool as possible so it doesn't start surrounding materials on fire, and let it expend its energy.... hence the big steel boxes in airplanes.

 

Sorry that the thread got hijacked into an LPF fire thread. I have no experiences yet with the Fireflys and am interested to learn.

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The Dreamliners do not use LFP, they use Lithium Cobalt. Same as Tesla or the Dell laptops that went up ion flames.

 

One of the big questions with the Vestas report, and not answered since, is this:

Did the battery cells them self fail when in contact with salt water. (I say unlikely.)

Or did the integrated BMS electronics fail when in contact with salt water and in turn shorted out the battery cells. (I much more unlikely.)

 

If you still have the two failed batteries from Vestas that is relatively easy forensics.

If not you don't have the failed batteries you need to invest about 5 grand and chuck one of them in the harbor for a few minutes to recreate the incident.

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I officially have a Firefly Oasis on order, it should be here in 2-4 weeks.

 

The biggest concern that I have with batteries on my little boat is physically fitting them. I really like to keep them on the port side for balance reasons (starboard has the head, cooler, and laz so it tends to list that way when loaded down for cruising). There isn't a lot of room on port, they have to fit under my quarterberth which is very low to make a double quarterberth fit at all on a 28' boat. I've been using AGM batteries because I can turn them on their side.

 

I had been considering LFP (which is an expensive upgrade, around $1500-$2000) just to get good capacity for a fridge while fitting batteries into my limited space.

 

On paper the deeper depth of discharge on the Firefly battery solves my problem for a whole lot less money. 75ah usable gives me 3 days of fridge use with zero solar or plugging in, which is enough for my needs (especially since I mostly cruise in the summer where I get more than enough solar to charge 25ah). It'll fit along with my starting battery where two group 24 AGM batteries (to get the same usable ah) did not.

 

I'll report back on how it's working for me at the end of the summer.

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VOR and in turn Mastervolt received uploads via sat from the Battery Monitoring System on each boat. Whether they have any data from the incident that enables them to add to the grounding report, who knows? That may come out in due course in the form of VOR boat system modifications.

 

Battery risks are essentially determined by their chemistry and different energy densities. Lithium Cobolt is one of highest, Lithium iron phosphate (LiFePo4) or LFP is a lot lower.

 

You will note by the report the Vestus LFP while a lot safer than cobolt chemistry, still kept on cooking all by itself sitting on the beach until it existed no more.

 

Like all batteries, lithium batteries regardless of chemistry consist of two electrodes separated by an electrolyte. Damage to the materials that keep the fragile elements of a lithium battery apart can lead to a short-circuit which in turn then causes a build-up of heat, which depending on the extent of cell damage can be excessive.

 

Lead acids behave completely differently where their volatility is related to excess hydrogen that may be produced during charging which can both physically damage the battery and can escape to be a fire risk.

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Argh! obvious error that should have read:

 

Did the battery cells them self fail when in contact with salt water. (I say unlikely.)

Or did the integrated BMS electronics fail when in contact with salt water and in turn shorted out the battery cells. (I say much more unlikely.)

 

Shorting out (power)electronics with salt water is simple, damaging sealed cells with salt water not so much.

(Salt water is not conductive enough to short out the cells either.)

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I officially have a Firefly Oasis on order, it should be here in 2-4 weeks.

 

The biggest concern that I have with batteries on my little boat is physically fitting them. I really like to keep them on the port side for balance reasons (starboard has the head, cooler, and laz so it tends to list that way when loaded down for cruising). There isn't a lot of room on port, they have to fit under my quarterberth which is very low to make a double quarterberth fit at all on a 28' boat. I've been using AGM batteries because I can turn them on their side.

 

I had been considering LFP (which is an expensive upgrade, around $1500-$2000) just to get good capacity for a fridge while fitting batteries into my limited space.

 

On paper the deeper depth of discharge on the Firefly battery solves my problem for a whole lot less money. 75ah usable gives me 3 days of fridge use with zero solar or plugging in, which is enough for my needs (especially since I mostly cruise in the summer where I get more than enough solar to charge 25ah). It'll fit along with my starting battery where two group 24 AGM batteries (to get the same usable ah) did not.

 

I'll report back on how it's working for me at the end of the summer.

 

 

I didn't think people in Seattle had refrigerators!?

 

I did hear on the morning weather that it was hotter in Portland than Miami yesterday!

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Titan and Playstation were not LFP but Cobalt which can thermal runaway and basically turn into a blow torch. LFP might overheat but do no catch fire.

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I didn't think people in Seattle had refrigerators!?

 

I did hear on the morning weather that it was hotter in Portland than Miami yesterday!

 

 

Air conditioning. You meant air conditioning, cuz without a fridge how would keep the beer cold? A veritable heat wave approaching the PNW though and there will be a lot of miserable people up there next week without air conditioning. Miserable people drinking cold beer at least.

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Titan and Playstation were not LFP but Cobalt which can thermal runaway and basically turn into a blow torch. LFP might overheat but do no catch fire.

Please cite evidence that Titan was cobolt not LFP....would be an interesting read.

 

Note: LFP gets hot enough to self destruct and to light up anything combustible.

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Titan was Li-Co.... heard it from the horses mouth. Easily searchable on Google. Yes, LFP can get very not when cells are overcharged and at something like 200C the cases melt.

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Titan was Li-Co.... heard it from the horses mouth. Easily searchable on Google. Yes, LFP can get very not when cells are overcharged and at something like 200C the cases melt.

Thanks for heads up. Never seen anything authorative about its battery chemistry on the interweb......I was simply told the shore powered charger was found to be fried but too hard to tell if that was the culprit or a consequence.

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Probably going a long way off topic but what the heck why not speculate as to why their batteries cooked.

 

Firstly if you look at photos below of the Mastervolt battery it is a bit hard to think how they could better engineer it. It looks very slick.

 

You might be right Chasm ...however the BMS and their individual cell shunts are moulded into the lid for protection. The only weak spot may be the individual cell circuits or connections for battery monitoring etc that you can see above the words “safe operation”. Bearing in mind batteries in these VOR boats are located in the lowest part of the bilge behind the keel and risk inundation first, those plugs/sockets in battery top may be a “weak link” with inundation?

 

Interestingly If you look at the schematic (and supported by the picture in link below showing the battery switching/monitoring enclosure in front of the twin alternators) it appears they only employ two(2) relays either side of the enclosure (yellow latches on top) on the charging side only. Mastervolt don’t appear to employ a “Dual Positive Bus” arrangement so that batteries are automatically disconnected from load if the low voltage threshold is suddenly reached.

 

Maybe they were due for a battery recharge just prior to the incident and post-crash there was a fault on the load side that caused the battery damage and not inundation?

 

That said the advertising schematic concentrates on battery management, charging and monitoring and I am not familiar enough with Mastervolt gear to say the battery load side is not voltage protected.

 

http://www.poweredbymastervolt.com/our-system-in-full-detail/

post-108919-0-05265000-1435383939_thumb.jpg

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Here is some interesting history which shows Firefly’s are arguably now at the same point LiFeP04 batteries were around five(6) years ago.

 

The Utube link below shows the Cleanster interviewing a very, very youthful Bruce Schwab with a Genesun LiFeP04 battery under his arm at the 2009 Annapolis Boat Show six (6) years ago. This is the same LFP battery that was aboard Alex Mevay’s (founder of Genesun) 21’ Pogo, (2) years prior to that in the 2007 Mini Transat. LFP were the battery of choice from then on in long distance raceboats starting with the Vendee Globe and VOR in 2008/09.

 

The interesting thing is looking at the Graph below showing Google Search Interest in the term LiFeP04 since its inception in 2007. The graph shows interest rose sharply over the first two(2) years to around when Bruce was interviewed in 2009, increased slightly more over the next three(3) years and then has plateaued off in the last three(3) years since 2012. The year 2012 was when Boeing had its Lithium Cobolt battery problems.

 

The most common responses you hear from people when Lithium sailboat installs are discussed is the technology is too new and everyone's waiting for the high capital cost to plummet. Is that true?

 

Firstly as indicated above it has been at least 6 – 8 years since the inception of the LFP marine battery, so it can hardly be called new technology anymore!!!! However as a comparison if you look at the slow initial take up to AGM's and Gel's in the 1980's over flooded lead acid's (well before sealed batteries became mandatory on race boats), then this viewpoint is maybe not unexpected.

 

Secondly, is the price of LFP going to drop much further? While the quality of LiFeP04 cells used for making a battery have both improved and become more diverse, the price in relation to cell quality has remained relatively static. The reliance for manufacture on a natural material that is not in wide abundance, increased demand leading to production scale being optimised and the fact that the true (inc charging) cost of LFP already matches, if not betters lead acid, says to me that quality LFP marine batteries will not drop significantly in price.

 

To support this view the battery that Bruce is holding in the Utube clip has not dropped in price (inc inflation) since that interview six(6) years ago!!! Other quality LEP battery system providers like Mastervolt and Victron, while more recent and having different price points, have also not dropped their prices. On the other hand quality AGM offerings have increased in price greater than inflation in the same period, no doubt on account of raw lead price increases.

 

Whis all mean for Firefly? Providing their patient and can fund the roll out, the future for Firefly Carbon Foam batteries looks very bright. It will be facinating in 5-6 years from now looking back at Firefly’s progression and take up by the market in comparison to LFP and other marine battery chemistries.

 

My only wish is I could get hold of some now outside the US. Nice sunnies Bruce.

 

https://youtu.be/JZ7vQJIwbzY

post-108919-0-25448600-1435903091_thumb.jpg

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Very very youthful? Cool, thanks! I feel younger already.

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The Dreamliners do not use LFP, they use Lithium Cobalt. Same as Tesla or the Dell laptops that went up ion flames.

 

One of the big questions with the Vestas report, and not answered since, is this:

Did the battery cells them self fail when in contact with salt water. (I say unlikely.)

Or did the integrated BMS electronics fail when in contact with salt water and in turn shorted out the battery cells. (I much more unlikely.)

 

If you still have the two failed batteries from Vestas that is relatively easy forensics.

If not you don't have the failed batteries you need to invest about 5 grand and chuck one of them in the harbor for a few minutes to recreate the incident.

Download and read the NTSB final report on the Dreamliner LiCo battery fires and the battery construction faults. The sub-sub Contractor had no experience with LiCo battery construction, the process and materials were faulty. The report will set your hair on fire!

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The benefit of Lithium Cobalt is their energy density, which is about 2.4x the energy density of LFP chemistry in small form factors. Where weight savings is worth the price premium of attention to safety, Lithium Cobalt can make sense. For most marine applications, this is not likely the case, even at the highest levels of sailing.

 

Lithium Cobalt batteries chemistry is prone to thermal runaway at temperatures as low as 130º C. As a result, charge monitoring and cell disconnect is crucial to the use of these cells in any application.

 

While it's possible to build a charge/discharge protection scheme that prevents thermal runaway, Lithium Cobalt is not a good choice if there is any possibility that the battery could be exposed to high heat from external sources. It's also the case that short circuits caused by physical damage could lead to internal discharge that raises the cell temperature to the point at which thermal runaway ensues.

 

LFP, by comparison, has a thermal runaway temperature of around 600º C and the batteries are not prone to developing high heat as a result of physical damage.

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^^

The question for me was why and how did the Vestas batteries fail, not what happened to the Dreamliner.

Basically, are they that salt water sensitive or did the internals physically break during the pounding on the reef and in turn short one or more of the cells.

 

I did read several of the publicly available Dreamliner reports. As I see it is fundamentally a (incomplete) risk assessment problem.

What is the price you pay for the weight savings gained by going LiCo vs. the industry standard NiCad systems? Basically a new fire hazard. The usual rule of thumb for LiCo is AFAIK the same volume of gasoline as the battery.

 

The next question would be along the lines of: Does this risk need to be mitigated and if so what are the options. Heavy fireproof box vs. choosing a safer chemistry in the first place.

 

LiFe is safer but heavier than LiCo, but still lighter than NiCad. (Conventional batteries also have interesting failure modes.) That said, it is hard to leave out the heavy fireproof box AFTER you had a fire problem... Public pressure and all of that.

 

And yeah. The Dreamliner battery construction was ...special.

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Energy storager costs are falling somewhere between 7 and 16% per year, depending on the research study. An internet search will yield many sources, some more recent that others. The electic vehicle market is driving these cost reductions. Tesla, even before it's massive lithium plant is built, will be selling it 7 kwh Powerwall unit, complete with BMS for $3,000 this summer. My cruising boat would be very happy with a unit half that size. Within 10 years, electric vehicles are projected to be cost competitive with gasoline vehicles.

 

Combined with the dramatic cost reductions in PV solar, over the next 10 years, the electric utility industry in sunny areas will be disrupted as homes and businesses install solar systems because they are cheaper. Oil based energy output will continue to drop as transportation and energy systems shift to solar-lithium, and the paranoia over climate change will seem silly.

 

Future's so bright, I gotta wear shades.

 

Sooner or later, your boat will have lithium.

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It looks like Firefly has all the advantages of a gel cell, without the disadvantages -- at around the same price, but cheaper when the cycle life is figured in. If only they were available smaller (50Ah would be fine for me).

 

What do you think?

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Energy storager costs are falling somewhere between 7 and 16% per year, depending on the research study. An internet search will yield many sources, some more recent that others......

That statement about storage costs is plain incorrect.

 

Over the last 8 or so years since their introduction the cost of quality lfp batteries has not fallen in real terms (before inflation). In the same period the cost of quality lead acid batteries has increased in real terms.

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It looks like Firefly has all the advantages of a gel cell, without the disadvantages -- at around the same price, but cheaper when the cycle life is figured in. If only they were available smaller (50Ah would be fine for me).

 

What do you think?

It would be nice to have more choice but the 31 or 110Ah truck battery format is a very popular size and it can be paralleled up to match larger formats.

 

The key advantage of Firefly's over any other lead acid chemistry is their greater usable capacity and ability to be used/cycled at a partial state of charge (SOC) without permanent loss in that usable capacity. This partial SOC use with limited charging time using an auxilliary engine alternator is usage typical of the majority of sailboats.

 

While not having the greater usable capacity, flat discharge, and high rate of charge of lithium, the Firefly's advantage is their "drop in" as a replacement to existing lead acid instalations without the additional costs including modifying charging systems in lithium instalations.

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What a fun read!! I feel more ignorant than when I started because I have an inkling now of the immense ness of that which I don't know

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What a fun read!! I feel more ignorant than when I started because I have an inkling now of the immense ness of that which I don't know

yeah, there are some pretty big nesses out there

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Titan and Playstation were not LFP but Cobalt which can thermal runaway and basically turn into a blow torch. LFP might overheat but do no catch fire.

PlayStation's battery was NiMH, made by GM Ovonics. It was similar to the battery used in the GM Gen2 EV1 car. The charger malfunctioned, overcharging the battery, which overheated and set fire to the resin in the battery box and hull.

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