Zora

Making Lithium Batteries?

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I did a search, but couldn't find much on it. 

Has anyone ever built their own  battery back for use on board as a house bank, out of the likes of 18650 batteries? I'm reading what i can, but some first hand experience/advice would be great. 

An example for a different application. It could be a cheap and not too difficult alternative to buying a ready to go bank by many 100 or 1000s.

https://www.adambender.info/post/lithium-battery-part-1-of-2

Thanks

Rhys

 

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Technically possible, of course, but the one-time expenses for the tooling (e.g. battery terminal spot welder) will offset any savings. Not to mention the fact that a typical 130Ah 12V battery has over 300 individual 18650 cells that all need to be matched electrically and connected properly. A fool's errand now that we're long past the hobbyist/tinkerer stage of lithium battery commercialization and commercial production by reputable manufacturers has reached scale.

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6 hours ago, IStream said:

Technically possible, of course, but the one-time expenses for the tooling (e.g. battery terminal spot welder) will offset any savings. Not to mention the fact that a typical 130Ah 12V battery has over 300 individual 18650 cells that all need to be matched electrically and connected properly. A fool's errand now that we're long past the hobbyist/tinkerer stage of lithium battery commercialization and commercial production by reputable manufacturers has reached scale.

Fair points. I do have access to a spot welder that could do it though. Are you in the states? It seems like you guys have a lot of options when it comes to lithium batteries, but here I only have victron which is about 1500 euro for a 100ah battery. 

If anyone knows of reasonably priced lithium batteries in Ireland or Uk I'd love to know of them. Maybe I've missed them in my searches. 

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6 hours ago, Max Rockatansky said:

What could go wrong? 

Have a look here... Jim, the proprietor, is a full time liveaboard in Marathon, a good guy

https://lithiummarinebattery.com/

Thank you for that, maybe he will ship to eu

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38 minutes ago, Zora said:

Fair points. I do have access to a spot welder that could do it though. Are you in the states? It seems like you guys have a lot of options when it comes to lithium batteries, but here I only have victron which is about 1500 euro for a 100ah battery. 

If anyone knows of reasonably priced lithium batteries in Ireland or Uk I'd love to know of them. Maybe I've missed them in my searches. 

LithiumWerks is based in NL and may have some solutions for you. Mastervolt may also.

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You really have to know what you're doing with Li-Ion; persistent cell imbalances can cause fires.  

I'd look at LFP instead of NMC as it's fundamentally safer and theoretically cheaper (though a bit bulkier); looks like that's what the guy linked before is using.  They're being made by the GWh now by many manufacturers, with automotive pack-level pricing to OEMs around $159/kWh from the last report I saw, and headed to $100/kWh by 2024.  At the module level they are cheaper still (no cooling, BMS, crash-tested enclosure, etc.)

Makes the prices we pay for marine stuff pretty painful (though $535/kWh from the linked site is actually better than what I'd been seeing).  Eventually it'll come down, particularly if we can start re-purposing automotive modules from wrecks, etc.  

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Stan Honey has an excellent write-up on the LiFePO4 bank he built using prismatic cells.  The battery management system (BMS) he used is no longer available, but there are reasonably priced options like the Orion Jr. 

I used Stan's plan to build a 300ah bank which has been working well for 3 years now.  Mine weighs about 90 pounds and replaced 6 golf cart batteries which weighed almost 400 pounds. 

Figure about $600 per 100ah 12V increment for the cells and shipping, plus cost of the BMS, contactor relay and a few odds and ends.

I'm not an expert, but I assume that building a large marine bank out of 18650 cells is not a good idea or somebody would written it up.  On the other hand, DIY LiFePO4 banks are pretty common and there are detailed instructions for the less technical among us to follow.

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We have been using a 400 a-hr  LiFePO4 battery bank in a Farrier F36/39 trimaran on a circumnavigation.  We left the Puget Sound in October of 2017 and are currently in the Bay of Islands, NZ.. We operate with no Battery Management System (BMS). It is my opinion that a BMScan  cause more problems than it solves. Thus far.... We have encountered a few other boats with lithium but we are the only one operating with no BMS.  It's rare to to do this because of the prevailing idea that you must have a BMS to be safe. I want to add to this discussion and say that this may be untrue  and the reverse may in fact be the case.  The only issues we have seen in the other boatrs with Lithium banks has been because of the BMS, either failing or drawing down the bank durring a layup. 

We spent $540 per 100 A-Hr. (12-volt)  no BMS . Try looking around here: http://store.evtv.me/proddetail.php?prod=ca100fi and look into a procedure known as "Bottom Balancing"

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There are definitely pros and cons of various BMS setups.   They can range from $50 to $1200 per pack.    Not having any BMS to monitor and balance individual cells can be done and I've know people that have.   If ANY sensor, board (and there can be many) or wire fails you will likely not have access to the power in your batteries.   If you buy a battery that has an integrated BMS inside the box and there is any such failure you will be without that battery basically indefinitely until it's sent back for repair or replacement.   If you have an external BMS, even with high/low cutoffs you can pre-wire or rewire underway directly to the pack bypassing the BMS in the event of an electronics, not battery failure.

No matter the battery type please setup your system with multiple packs for redundancy.

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I'm going to make my own battery in the new year. I want the highest capacity to fit in a restricted space and make them modulised to keep each assembly light weight. After a fair bit of research, I'll be choosing aluminium case prismatic LiFePo4 cells because they have the best power density in this chemistry. Don't use 18650 cells because you'll need a zillion of them and each one needs to be balanced and the chemistry isn't really safe enough for use on a boat in big capacities. Might be fine for a Tesla where you can bail out easily enough if it bursts into flame, but a boat is a pretty inconvenient for doing the same thing.

If you haven't seen it, this guy's youtube channel has a lot of good info. He's a young fellow but has a reasonable grasp of the subject and no shortage of enthusiasm.

https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q

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One of my good friends is one of those super smart electrical engineers in the States. He has about 20 patents. Many of his early ones are for recharging lithium batteries. He was one of the first persons to build a car battery out of 150 cells that are used in laptops. He used to buy them by the bag. His batteries are on the B2 Bomber and several satellites. Tesla licensed some of his patents to do their car batteries. 
 

The trick is in the charging. Any idiot can gang up a bunch of cells and call it a battery. Lithium are tricky. They can catch fire. You need constant monitoring and individual charging of every cell. Take a look at a modern cordless tool battery. My Makita ones have a large fancy circuit board that looks important. 
 

I would stay away from building a lithium simply because of cost and possible failure rate. 

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Lithium are tricky. They can catch fire.

Not all.     And the cost of lithium is less than that of flooded cells when you take into account lifespan, useable capacity, etc.

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On 12/19/2019 at 10:17 AM, Toecutter's Ghost said:

Don't use 18650 cells because you'll need a zillion of them and each one needs to be balanced and the chemistry isn't really safe enough for use on a boat in big capacities.

18650 is a case size, not a chemistry. 

The problems I've seen in series / parallel setups have been related to the weak cells in the parallel strings getting stressed and hot. BMS's I've looked at monitor the parallel strings as if they were single cells. That is simple but not ideal.

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I don’t know a damned thing about your needs or filLing them...

but... I just purchased a Greenworks 60 volt lithium battery chainsaw with two 2.5 amp batteries and ran the hell out of it for six days. ($250 plus $20.75 tax) It took about the Same amount of time to drain both batteries as I could work before testing or eating lunch. I may never even try to start my gas chainsaw before selling or giving it away. Battery powered stuff is really getting to be fantastic. 
The batteries also fit a lawnmower, weed whacker, hedge trimmer, and leaf blower. I didn’t buy any of those. 

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22 hours ago, weightless said:

18650 is a case size, not a chemistry. 

The problems I've seen in series / parallel setups have been related to the weak cells in the parallel strings getting stressed and hot. BMS's I've looked at monitor the parallel strings as if they were single cells. That is simple but not ideal.

True, but 18650's are somewhat notorious for being dubiously specified in the budget price range since they are essentially the "AA" battery of lithium chemistries and there's no mention of chemistries in the OP's link. In fact, the Samsung battery mentioned is regular Li and is brilliant for rebuilding power tool packs. If you're after LFP, first check is to make sure they're 3.2 VDC and not 3.7VDC when charged, I guess.

If you buy batteries already fitted with spot welded nickel tabs they are ridiculously easy to solder together.

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3 hours ago, Toecutter's Ghost said:

 there's no mention of chemistries in the OP's link.

 

Yep but doesn't your post say that 18650s are unsafe because of their chemistry?

On 12/19/2019 at 10:17 AM, Toecutter's Ghost said:

Don't use 18650 cells because ... the chemistry isn't really safe enough for use on a boat

I just wanted to make it clear that LiFePO4 and all the other common lithium-ion chemistries are available in 18650. In any case (as it were) I believe the current wisdom is that LiFePO4 is the best Lithium-ion chemistry for boat batteries.

 

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13 minutes ago, weightless said:

Yep but doesn't your post say that 18650s are unsafe because of their chemistry?

I just wanted to make it clear that LiFePO4 and all the other common lithium-ion chemistries are available in 18650. In any case (as it were) I believe the current wisdom is that LiFePO4 is the best Lithium-ion chemistry for boat batteries.

 

Fair enough, but the OP's link isn't discussing LFP batteries. It's discussing "regular" run of the mill batteries. it also mentions (to paraphrase from memory) that batteries "should be between 3 and 4 volts". This might work for a scooter repack that individually monitors each cell, but scaled up to, say, a 1kW battery? I dunno.

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1 hour ago, Toecutter's Ghost said:

Fair enough, but the OP's link isn't discussing LFP batteries. It's discussing "regular" run of the mill batteries. it also mentions (to paraphrase from memory) that batteries "should be between 3 and 4 volts". This might work for a scooter repack that individually monitors each cell, but scaled up to, say, a 1kW battery? I dunno.

Got it. Yes, the OP's link is to a battery build using LCO cells. I think nominally over 40 volts and just about six amp hours. I hadn't looked at it before. The OP said he wanted a house bank. ¯\_(ツ)_/¯

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