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3 year Battle Born Capacity issue

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Jimmyzshack

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Jan 23, 2022
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Looks like i have a problem with my Battle Born batteries. After 3 years having 2 (BB10012) in parallel in my RV, i started to expand my solar on the roof and do a capacity test on my 2 Battle Born batteries. I was pretty shocked to find one was down to 52.4 amps (653wh) and the other one at 87 amps (1087wh) this was after i pulled them out of the rv as i only got 142amps on the victron shunt when i ran the test. They have always been on a victron shunt and it shows the total discharge energy over this time period to be 122.2 kwh (we do not dry camp very often.) I know they should be cover by warranty, i'll be calling tomorrow to see what they say. Hard to find where anyone else has posted stats after years of use on battle born batteries here or anywhere else.

anyone else have stats on theirs after a few years of use?
 
Jimmyzshack said:
Looks like i have a problem with my Battle Born batteries. After 3 years having 2 (BB10012) in parallel in my RV, i started to expand my solar on the roof and do a capacity test on my 2 Battle Born batteries. I was pretty shocked to find one was down to 52.4 amps (653wh) and the other one at 87 amps (1087wh) this was after i pulled them out of the rv as i only got 142amps on the victron shunt when i ran the test. They have always been on a victron shunt and it shows the total discharge energy over this time period to be 122.2 kwh (we do not dry camp very often.) I know they should be cover by warranty, i'll be calling tomorrow to see what they say. Hard to find where anyone else has posted stats after years of use on battle born batteries here or anywhere else.

anyone else have stats on theirs after a few years of use?
Click to expand...

Please keep us updated on how BB handles this.

Curious - did you keep them floated when not in use?
 
Jimmyzshack said:
11.5 on the inverter. they have never been down to bms or inverter low voltage cut off other than doing the capacity test though.
Click to expand...
The only thing left to check is your bulk/absorb but Battleborn says you can charge to 14.6 volts.
I think they even encourage it.
I don't think you have done anything wrong and I'm sure lots of customers do much worse.
Hope they help you out.
 
I am sure Battle Born is going to tell you to charge them to 14.2v for a while to balance the cells.

If you did not take them above 13.4v you never balanced them to any significant degree. When the cells get out of balance they will be at different state of charge levels which will have some effect on each cell's internal impedance which means the lower net impedance battery will dominate the supply current.

The greater the discharge rate you put on the batteries the faster they will become imbalanced.
 
RCinFLA said:
I am sure Battle Born is going to tell you to charge them to 14.2v for a while to balance the cells.

If you did not take them above 13.4v you never balanced them to any significant degree. When the cells get out of balance they will be at different state of charge levels which will have some effect on each cell's internal impedance which means the lower net impedance battery will dominate the supply current.

The greater the discharge rate you put on the batteries the faster they will become imbalanced.
Click to expand...
Absorption was 14.4 on the inverter/charger float was 13.4
 
I would talk to BB and see what they have to say.

I see a few possible contributing factors.
  1. As @RCinFLA mentioned, it may be that charging to a higher voltage (~14.2-14.5ish) and letting the BMS balance the cells might have a positive effect.
  2. My understanding is that the two primary causes of calendar aging (that is aging/degradtion independent of cycling) are:
    1. high temperatures for extended periods of time
    2. high state of charge for extended periods of time
On point 2, even though as others have alluded to, 13.4V is a totally reasonable float voltage, I think it is not a reasonable long term storage voltage if I'm understanding things correctly (I think 50% SOC +/- 20 is what you want for long term storage). It may be that if it was held there for years, in combination with being stored in higher temperatures for much of the year (am I correct in assuming you live in a hot climate?) calendar aging is occurring at an accelerated rate. But even at an accelerated rate, I couldn't imagine seeing the numbers you are seeingafter 3 years, at least with the lower capacity battery.
 
Jimmyzshack said:
Absorption was 14.4 on the inverter/charger float was 13.4
Click to expand...
If we can't float Battleborn batteries at 3.35 volts per for extended periods, I would guess we can't float any LFP battery at 3.35 volts per for extended periods. Definetly watching this thread.
 
The piece of info missing in attached video is the time necessary to hold 14.2 to 14.4v.

I am not sure what their BMS balancing current is but likely 100 mA, once a cell gets above 3.4v. (A 'cell' in Battle Born 12v battery is thirty 3.4 AH cylindrical cells in parallel with four of these groups in series)

To put in perspective, if 100 mA balancing then it would take 10 hours to knock off 1 AH or 1% of 100 AH cell misbalance state of charge.

More than about 1-2% out of balance is likely to give you a BMS cell overvoltage shutdown as you approach 14.4v with the highest SOC cell running up to overvoltage limit before lower SOC charge cells get near full charge. The battery BMS will continue to bleed overvoltage cell after overvoltage shutdown so the battery will eventually come into balance, just will take a lot longer time to wait for any overvoltage recoveries.

You have to continue to bulk voltage charge after BMS overvoltage clears to allow time for lower SOC cells to reach full charge. You may get multiple overvoltage BMS shutdowns along the way.

 
Last edited:
Following. My understanding is LFP is a lower voltage chemistry and therefore has very minimal voltage driven aging compared to say NMC. This is why Battleborn says floating at 13.6v is "perfect" as the battery will just sit at 100% without taking any additional charge and that for storage they should be charged to 100% first, because high SOC makes little difference while hitting low SOC in storage is a bad situation.

Tesla seems to recommend keeping LFP version charged to 100% rather than the 80% on the NMC versions:

If your vehicle is equipped with an LFP Battery, Tesla recommends that you keep your charge limit set to 100%, even for daily use, and that you also fully charge to 100% at least once per week. If Model 3 has been parked for longer than a week, Tesla recommends driving as you normally would and charge to 100% at your earliest convenience.
Click to expand...

https://www.tesla.com/ownersmanual/model3/en_jo/GUID-7FE78D73-0A17-47C4-B21B-54F641FFAEF4.html

I would imagine they recommend the recharge to 100% to get the balance to occur, I am going to guess thats the issue here as well is cells are out of balance as they where floated but rarely absorbed to hit balancing voltage threshold.

I am glad I have SOK batteries so I can open them up and check cell voltage and manually balance if necessary, although a Bluetooth BMS would also allow you to see individual cell voltages as well.

I currently float my SOK's at 13.6v in my RV to keep the 12v system running even in storage but have debated switching my charger to CC/CV and basically have it cycle after hitting a recharge voltage threshold of say 13v. Not sure whats better of the battery long term.
 
Last edited:
for now on the one that tested the lowest 52.4 amps (653wh) i have put a charger i have that has a power supply mode at 14.1v and it seems to be taking 3 watts to zero over and over for the past 8 hours. I tried at 14.2 but the bms was disconnecting. My setup of the inverter at the time of install came from battle born website for the inverter. https://battlebornbatteries.com/bat...with-xantrex-xc2000-in-trailer-life-magazine/

i'll run another test after it sits at the 14.1 for 24 hours and see if it makes a difference.
 
The email messaging works pretty good. Takes a couple of days but you get a response from a tech who seems to know his stuff. And a name for follow up.
 
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