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Spin Echo

Balmar Smartgauge Battery Monitor

21 posts in this topic

I will be installing a battery monitor for my 2x 4D house bank and was thinking of getting the Balmar smartgauge. If anyone has any experience with it please share your experience. Thank you.

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Any update?

 

I am starting to look at battery monitors and was curious how you like the the Balmar. It seems to have a KISS installation.

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Istream thanks for the link. Gotta love Main Sail's work!!

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Istream thanks for the link. Gotta love Main Sail's work!!

Yup, an asset to the community.

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I'll be devil's advocate. I'm not a huge fan of secret sauce. Somehow this thing knows what your battery capacity is. Except everything on boats breaks and if you don't understand how it works then the potential for havoc just increases.

 

I have the Victron. Yeah you have to put in a shunt and pull the ethernet cable so there is some installation pain. But not much worse than the Balmar. What it does give you is an accurate ammeter. I like to know how many amps are going in or out at any given time. This tells me if my charging is working as intended and also if I have an unexpected load. Also it allows you to audit which appliances/circuits draw what current. You can probably do all of these with a clamp on ammeter, I like having the tool wired in.

 

I have a fair bit of experience with electrical systems and I'm not afraid of maintaining boats. For someone who just wants to install and forget it, then by all means smart meter on!

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I'll be devil's advocate. I'm not a huge fan of secret sauce. Somehow this thing knows what your battery capacity is. Except everything on boats breaks and if you don't understand how it works then the potential for havoc just increases.

 

I have the Victron. Yeah you have to put in a shunt and pull the ethernet cable so there is some installation pain. But not much worse than the Balmar. What it does give you is an accurate ammeter. I like to know how many amps are going in or out at any given time. This tells me if my charging is working as intended and also if I have an unexpected load. Also it allows you to audit which appliances/circuits draw what current. You can probably do all of these with a clamp on ammeter, I like having the tool wired in.

 

I have a fair bit of experience with electrical systems and I'm not afraid of maintaining boats. For someone who just wants to install and forget it, then by all means smart meter on!

I think this is a very valid point. The shunt-based systems also have voltage sense wires so in principle, there's no reason Victron, Xantrex (hah!) or someone else couldn't come up with a shunt-based unit that gives you both a battery capacity estimate based on voltage sense information and the current flow information that's so useful for the reasons you mention.

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Afterguy's post begs a follow-up question. Balmar's smart meter was designed to make installation easier, since there were many installations that had been done wrong. How can you mess-up the installation of a shunt??

 

The installation of a shunt seems straight forward. The shunt goes between the negative terminal of the battery and the load (bus). First take the wire from battery and connect it the shunt. Fabricate a wire to go from the shunt to the battery. Then connect the monitoring wires.

 

How can you mess this up? Or am I missing something?

 

Thanks

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The problems I have heard about and seen have been with people adding "things" after installing the shunt and presumably following instructions that say to connect that particular "thing" direct to the battery. You then have a mess of ground wires that are connected to the battery on the wrong side of the shunt. Obviously this is bad practice for many reasons, but a surprising number of the manuals for electronics (VHF radios, etc) seem to assume that you are installing on a runabout with no switch panel etc, and just say connect to the battery with the included fuse.

 

Mark.

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The problems I have heard about and seen have been with people adding "things" after installing the shunt and presumably following instructions that say to connect that particular "thing" direct to the battery. You then have a mess of ground wires that are connected to the battery on the wrong side of the shunt. Obviously this is bad practice for many reasons, but a surprising number of the manuals for electronics (VHF radios, etc) seem to assume that you are installing on a runabout with no switch panel etc, and just say connect to the battery with the included fuse.

 

Mark.

This. Also, the shunt based systems don't account for loss of bank capacity over time, so if you're pushing the envelope and draining the bank to or below 50% on a regular basis, they can lead you to believe that you're doing less harm than you thought. The Smart Gauge is supposed to adapt and give you an accurate C automatically.

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My problem with it is it only gives State of Charge, and if we believe the tests, does that accurately on the present capacity of the battery bank - which is changing. SOC is for me the least useful number. I do not agree with Maine Sail that this is all you need to know. What I want to know is: How many amp hours have I used? and therefore, How many amp hours do I need to replace? Thirdly, how many amp hours do I have left? SOC by itself gives you none of this information without also knowing the capacity of the battery (which varies with time) and doing some math. I rarely look at the SOC indication on my battery meters (Mastervolt and Blue Sky, which track pretty closely most of the time).

 

From this view, the notion that an AH counter becomes less accurate as the battery ages is incorrect. It's estimation of SOC becomes less accurate to the extent that the capacity has changed, however I believe that to be of little consequence. The energy drained from the battery (and the energy that must be replaced) is accurately measured over time, while the SOC estimated by the Balmar gives you little clue as to how much energy was used or replaced as the capacity changes.

 

This is the "dumbed down" meter: easy to install and giving a single number that a child can understand, but which conveys far less information than you would like to have. The singular advantage is that you can more accurately estimate depth of discharge, useful to know occasionally but in my mind very secondary to other data. With very little attention, you can estimate the current capacity of the bank by its voltage compared to AH used, and adjust your AH meter (or better still, just your thinking) accordingly.

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DDW makes a couple of really great points. Knowing SOC without any AH numbers is like knowing the tank is half full without knowing the size of the tank. If there whole point is that the tank size changes constant, then what good does it do to know what's in it without knowing its size? The whole Balmar story just doesn't add up.

 

From my point of view, what's worse is the black-magic approach to SOC determination. I'm not aware of any way to determine SOC that's reliable across the range of battery technologies in use today - Flooded, Gel, AGM, Lithium-Manganese, Lithium-Iron-Phosphate and others. If it's so clever, get a patent.

 

Until there's some disclosure, I remain dubious of products from a company that paints their alternators and claims that Lithium batteries require a different alternator/regulator solution from any other battery technology.

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I've been waiting for more feedback on the new Balmar unit as well but likely will just have to purchase one to test out.

 

Lithium packs usually have the same issue with the SOC meters that are on the market since the discharge curve is very flat. The lithium-carbon banks I've been installing have a nice linear discharge so the voltage can be easily used as a SOC indicator but we still use off the shelf, shunt-base, Amp/Hour meters to augment that data. I really like the Victron unit as it provides hundredths, not just tenths like many models.

 

I've never heard Balmar claim that they recommend a different alternator/regulator combo. In fact years ago I worked with them to come up with charging parameters that work well with their standard regulators. Mainly it involves using the belt slip setting (to reduce the field output) to not overheat their alternators that can't put out their stated rate "continuously".... which is my biggest rant against them.

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I guess the focus on SOC comes from people's familiarity with a gas gage in a car. Even there, it's a pretty useless number. Give me gallons used and gallons left please.

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Solo, look here and search for Lithium. They have all kinds of "reasons" why Lithium batteries are different when the real problem is that their alternators, as you say, can't put out their rated output. A good part of why they can't is that the powder coat really limits the amount of heat the alternator case can dissipate. In fact, the only alternator they claim can be used with Lithium batteries is unpainted!

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Moon, I don't think painting an alternator is really all that bad. In fact my large alternator was painted by the manufacturer (Electodyne), and intended for much more severe service than anything Balmar contemplates. Which is not to excuse Balmar for not rating their alternators honestly. Do you have a link to some definitive tests on painted vs. unpainted performance? Given the film thickness of paint - even powder coat - the R value would be almost vanishingly small.

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Powder coat is essentially polyester, which is a remarkably good thermal isolator. It just doesn't conduct heat very well at all.

 

Raw aluminum has a coefficient of thermal conductivity that's more than 4000 times that of polyester. Seems to me that means that a powder coat of .001" decreases the thermal conductivity of a 4" thick piece of aluminum by 50%. Is my math wrong?

 

I'm not aware of anyone that's modeled the effects on an alternator case - but why on earth would you coat a heat source with a thermal insulator?

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To keep it from corroding

 

Powder coat is essentially polyester, which is a remarkably good thermal isolator. It just doesn't conduct heat very well at all.

 

Raw aluminum has a coefficient of thermal conductivity that's more than 4000 times that of polyester. Seems to me that means that a powder coat of .001" decreases the thermal conductivity of a 4" thick piece of aluminum by 50%. Is my math wrong?

 

I'm not aware of anyone that's modeled the effects on an alternator case - but why on earth would you coat a heat source with a thermal insulator?

 

To keep it from corroding in the sometimes hostile environment of a marine engine room?

 

How much paint hinders heat transfer is a function of the relative contribution to cooling provided by convection, conduction, and radiant emission. My guess is that 80% or more of alternator cooling is due to convection via the air pumped through it by the fan and the paint's not going to hurt you there. The remaining heat is probably mostly dumped via radiative cooling and even white paint (one of the worst colors for radiation) isn't gonna hurt you that much compared to aluminum oxide. Paint will hurt conduction but the only place the alternator can conduct to is the engine block and it's probably close to the same temp as the alternator, so not much heat transfer there (or even possibly in the wrong direction if the block is hotter), and even when the block is cold there's not much contact area for the paint to interfere with.

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Powder coat is essentially polyester, which is a remarkably good thermal isolator. It just doesn't conduct heat very well at all.

 

Raw aluminum has a coefficient of thermal conductivity that's more than 4000 times that of polyester. Seems to me that means that a powder coat of .001" decreases the thermal conductivity of a 4" thick piece of aluminum by 50%. Is my math wrong?

 

I'm not aware of anyone that's modeled the effects on an alternator case - but why on earth would you coat a heat source with a thermal insulator?

It isn't that simple. Most of the heat will be rejected through conduction to the forced air. There is an air film sticking to the surface that is a pretty good insulator too. Maybe thicker next to a rough and porous aluminum surface vs. smooth painted. Some will be radiated and again the paint may actually have better emissivity than the aluminum. Also only the exterior case is painted, how much surface area isn't, how much heat generated in the stator vs. rotor. Too many variables and confounding factors. That's why I'm "from Missouri" on this one - show me the data. I know a lot of people say as you do, but I have never seen any evidence to back it.

 

Purely conducted through the paint layer, lets say polyester is about R5. That means 0.005" coating is R0.025. It isn't hard to get an alternator case to 150 deg while shedding 1000 BTU or so, if it has a half a square foot of surface area the effective average R value is 0.16. That makes paint look significant (adding about 15%), but as I said, it isn't going to be that simple. Be happy to look at some test results though!

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