Strange behavior with Battle Born battery. Battery dead when it should still have charge??

[Vannautical engineer]

I have a Battle Born 12V 100ah battery. I rarely drain it very far. I think the lowest I have ever seen it was about 60%. My main way of monitoring it is using one of those cheap generic battery capacity monitors that use a smart shunt. Lately I have been leaving the solar panels disconnected when I park the vehicle and leave it unused for a while, because there's no need for the battery to be fully charged. Last time I left it, the battery charge showed around 80%. However, I used it recently, still leaving the solar disconnected because I thought I had plenty of battery, and the battery died. When I reconnected the solar panels and the battery monitor came back to life, the voltage was in the 10V range.

I don't understand why the battery died when, according to the monitor, it should have still had about 75% charge. The battery is about two and a half years old. Even stranger, when I pulled up my Renogy charger app (Renogy DCC50S) it initially showed the battery status as "over discharged" and it showed it at 0% charge, but then after charging it just for about 15min at 10amps, it showed it back up at 80% charge.

I'm not sure if the battery is going bad (I hope not, it's not that old, and there's not a ton of cycles on it) or if it's just a weird discrepancy with the monitoring. It's worth noting that I'm in Michigan, so the battery has been in the vehicle at cold ambient temps, but I was under the impression LifeP04s weren't discharged by the cold very much.

 

[bullfrog !]

Glad you asked this question. I’ll be interested to see the answer! Hopefully it will be something simple that can easily be taken care of like resetting the BMS maybe?

 

[peteg59]

Cold does affect batteries, and not in good ways.
I'm under the impression that lithium batteries should not be discharged, often, below 50%.

Hopefully it hasn't damaged the battery beyond its useful life.
Best of luck, and keep us posted how this works out for you...

 

[Vannautical engineer]

Cold does affect batteries, and not in good ways.
I'm under the impression that lithium batteries should not be discharged, often, below 50%.

Hopefully it hasn't damaged the battery beyond its useful life.
Best of luck, and keep us posted how this works out for you...

Um, isn't the 50% thing strictly for lead acid batteries? I'm pretty sure the advantage of Lithium, especially LiFe, is that they DON'T have an issue discharging below 50%. I mean, cell phones have never had this problem.

Also, Battle Born themselves say they can be stored down to -15deg F.

https://battlebornbatteries.com/faq-how-to-winterize-your-batteries/

 

[INTJohn]

BattleBorn supposedly is very reputable and has good service. I would be directing all this OP info to them.

INTJohn

 

[wayne49]

Deleted as not useful to the main issue.

 

[rruff]

If I'm reading you correctly, you parked it at 80%, left it for a time (how long?), then came back to use it and the battery was dead (shut off due to low voltage). I'd guess that a load you weren't aware of was the culprit.

These batteries are supposed to just sit for a long time with no problems. And they can do that at any charge level, but it's better if they are not at the extremes of their range... fully discharged, or fully charged. 80% would be fine for years.

The battery should never get as low as 10v, and the BMS should prevent that. Do you have a multimeter you can check it with? What charge controller do you use? I'd fully charge and fully discharge to see what capacity you have and if everything is operating correctly now. It may not be the battery at all.

 

[Vannautical engineer]

If I'm reading you correctly, you parked it at 80%, left it for a time (how long?), then came back to use it and the battery was dead (shut off due to low voltage). I'd guess that a load you weren't aware of was the culprit.

These batteries are supposed to just sit for a long time with no problems. And they can do that at any charge level, but it's better if they are not at the extremes of their range... fully discharged, or fully charged. 80% would be fine for years.

The battery should never get as low as 10v, and the BMS should prevent that. Do you have a multimeter you can check it with? What charge controller do you use? I'd fully charge and fully discharge to see what capacity you have and if everything is operating correctly now. It may not be the battery at all.

It sat for maybe three months at most.

I would agree that this sounds like there was some load I wasn't aware of draining the battery, but I have the shunt measuring the current in and out of the battery directly on the negative cable right at the battery. No current can get in our out without passing through the shunt. If there was a load I wasn't aware of, shouldn't it have registered on the battery capacity monitor, and slowly depleted the charge percentage shown on the capacity monitor as a result? Maybe the shunt is not sensitive enough to see a very small current drain?

That's the crux of the whole thing, why does my capacity monitor still show about 75% when the battery itself is drained, unless the battery self discharged by 75% all by itself, which seems unlikely.

For the time being I'm just going to let it charge with the solar panels and see what it does. The voltage as measured by the capacity monitor is already back over 12V.

 

[wayne49]

Some lithium batteries have heating elements built in, and with the charging source disconnected during cold weather, the battery would probably drain to the shut off point. The heater load may not show up externally.

Is there a reason to shut off the solar charging system? Parked inside?

 

[rruff]

For the time being I'm just going to let it charge with the solar panels and see what it does. The voltage as measured by the capacity monitor is already back over 12V.

Good idea. If you can fully charge it and then fully drain it... and measure the capacity with something besides the monitor, that will tell you something regarding the battery. Or it could just be the monitor. Maybe something failed in that and it drained your battery? Or if it was still on, that could have been it. You can tell a lot regarding SOC just by measuring voltage accurately. If you don't have a multimeter, it would be a good time to get one I think.

 

[rruff]

Some lithium batteries have heating elements built in, and with the charging source disconnected during cold weather, the battery would probably drain to the shut off point. The heater load may not show up externally.

The way I've heard they work is that the input energy is what warms them. For instance if sun hits your panels in the morning and your batteries are below freezing, the energy switches to the heating element until the batteries are warm enough. They aren't maintained at above freezing unless you are charging. There might be setting where the heating will turn on regardless, but that would be really cold.

 

[tx2sturgis]

My main way of monitoring it is using one of those cheap generic battery capacity monitors that use a smart shunt. Lately I have been leaving the solar panels disconnected when I park the vehicle and leave it unused for a while, because there's no need for the battery to be fully charged

That's the crux of the whole thing, why does my capacity monitor still show about 75% when the battery itself is drained, unless the battery self discharged by 75% all by itself, which seems unlikely.
For the time being I'm just going to let it charge with the solar panels and see what it does. The voltage as measured by the capacity monitor is already back over 12V.

I dont trust your 'cheap generic battery monitor' and until proven otherwise, I suspect your solar charge controller is either not fully compatible with lifepo4, or if it is, it is either struggling with low solar inputs from your solar panels (this time of year with low sun angles it can happen) or it is set (or booted up) for FLA or AGM and its not pushing the Battle Born battery up to full charge.

It sounds like you are assuming the failure is the $1000 battery and not the $25 battery monitor or the $40 charge controller. I'm making a point, not saying those are the exact prices you paid.

Your battery monitor may be calibrated incorrectly, or your charge controller may be undercharging the battery. I've seen that happen.

I've been using a Battle Born 100ah battery now for about 6 years in varied applications and every single time I thought I was having a battery problem, it turned out to be a defective charger, a blown fuse, a loose connection, a failed meter, cold temps that shut down the BMS, or some other issue.

I've accidentally taken my Battle Born battery all the way down to shutoff, probably 10 percent or so, and it easily recovered once the charger's problem was rectified. When the BMS shuts down, some chargers and monitors interpret this protective 'sleep mode' as a dead battery.

What I'm saying is: Until you can prove or disprove the battery is under-performing, suspect your other components first.

Also, I would not 'store' a large expensive lifepo4 battery long term (1 month to 1 year is long term for a battery) with anything attached to the terminals (except a lithium compatible charger).

If you're going to store it un-used, with no input charge, you should bring it to around 50% to about 75% charge if possible and then disconnect both terminals for the duration. Especially the charge controller (and battery monitor): because without solar input, that's a 'load': it's sampling battery voltage 24/7 and has to pull a tiny amount of battery current to keep itself alive and waiting for solar input.

These are my suggestions based on my experiences. Good luck.

 

[MotorVation]

I would fully charge it and hold it at 14.4 volts for 30 minutes (absorption) to balance the cells. Those are the specs Battleborn gave me when I first bought mine

 

[Happy Camper]

Regarding the heating of the battery.

As I recall you can't charge a lithium battery below freezing without killing it. I would imagine that it can't use external energy to heat itself sure to the chance of self destructing.

So it might default to heating itself using stored power.

Let us know what battle born says. Genuinely curious.

 

[jonyjoe303]

which meter do you have? I been using the TK15 for years on my 220ah lifepo4 and has been very reliable. But any coulombcounter has to be properly calibrated the first time or the reading will be off.
10 volts while low for a battleborn won't damage it longterm, the voltage range for an individual lifepo4 cell is between 2.5 and 3.65 volts, since a battleborn is a 4s battery the range would be 10 - 14.6 volts. The BMS worked as advertised and stop the discharge at its minimum range.

TK15 meter (paid about 30 dollars for 50amp model) that I been using, it has to be calibrated both at the high end and also at the low end of the battery voltage range and also has to know the battery capacity. Once you enter all the correct settings, you need to slow charge the battery to full when it reaches max voltage that you set the meter will read 100 percent.
Example if the max voltage is 14.4 volts, the battery terminals has to reach 14.4 volts otherwise it won't read 100 percent. If you fast charge the battery, the battery terminals might reach 14.4 volts too soon and won't be properly calibrated.

When I won't be using the battery, I disconnect everything at the battery terminals.

 

[NctryBen]

I dont trust your 'cheap generic battery monitor' and until proven otherwise, I suspect your solar charge controller is either not fully compatible with lifepo4, or if it is, it is either struggling with low solar inputs from your solar panels (this time of year with low sun angles it can happen) or it is set (or booted up) for FLA or AGM and its not pushing the Battle Born battery up to full charge.

It sounds like you are assuming the failure is the $1000 battery and not the $25 battery monitor or the $40 charge controller. I'm making a point, not saying those are the exact prices you paid.

Your battery monitor may be calibrated incorrectly, or your charge controller may be undercharging the battery. I've seen that happen.

I've been using a Battle Born 100ah battery now for about 6 years in varied applications and every single time I thought I was having a battery problem, it turned out to be a defective charger, a blown fuse, a loose connection, a failed meter, cold temps that shut down the BMS, or some other issue.

I've accidentally taken my Battle Born battery all the way down to shutoff, probably 10 percent or so, and it easily recovered once the charger's problem was rectified. When the BMS shuts down, some chargers and monitors interpret this protective 'sleep mode' as a dead battery.

What I'm saying is: Until you can prove or disprove the battery is under-performing, suspect your other components first.

Also, I would not 'store' a large expensive lifepo4 battery long term (1 month to 1 year is long term for a battery) with anything attached to the terminals (except a lithium compatible charger).

If you're going to store it un-used, with no input charge, you should bring it to around 50% to about 75% charge if possible and then disconnect both terminals for the duration. Especially the charge controller (and battery monitor): because without solar input, that's a 'load': it's sampling battery voltage 24/7 and has to pull a tiny amount of battery current to keep itself alive and waiting for solar input.

These are my suggestions based on my experiences. Good luck.

I’ve had the same experiences with mine. I thought the internal heat was the biggest possibility if so equipped in this situation. One time I had to get mine going due to it totally discharged in which I used a “smart” battery charger. I now have four 100ah battle borns in my camper and very happy. Balancing them is important and using a quality mppt controller I feel is important also. I found Renergy to be mediocre compared to the more top of the line stuff. But, I haven’t had a chance to shut mine down for an extended period. But just monitoring the better system I see a huge difference.

 

[Vannautical engineer]

which meter do you have?

I'm using one of these. I forget if I calibrated it when I first put it in, or if this model even has that same type of calibration, so that's probably the issue. I know I set it to the correct 100ah capacity, but that's all I remember doing.

 

[TravelinTom]

Two thoughts to add.
Your monitor is one possible drain over time. Best to completely disconnect battery posts in storage.
Second; electrons need to be excited with high voltages to move across dead cells. Thus BB recommends certain Lithium chargers. It'll have to hit 14.4 volts or more until it reaches absorption mode and hold until float. We've left our solar connected to maintain full charge considering it's not always getting sunlight.
We've experienced a faulty PD charger and found it blew a fuse. This is our current unit;
Progressive dynamics 80ah
PD9180ALV. (Etrailer) $317
We could have gone to PD9160 for our BB Gamechanger.