I REALLY messed up. (cold temps/deeply discharged LiPo)

[Stephen Shreds]

I had been away from my van for a month in Alaska. just before I left I installed the renogy dc to dc charger as my solar wasn't working as well as I thought it would. when I installed it I installed the positive to a bus bar after the turn off switch. well I had for got that I installed it that way and had my friend turn on the van every two weeks to charge the battery as a 10 watt heating pad to keep the battery warm. Well as it states the battery was not getting a charge and now the battery is dead and is reading only 2volts!

A this point I have two options.

1. Remove the battery and put it in heated storage until it is at proper charging temps.

2. Keep the battery installed and run a mr buddy heater by it all night and try to charge it in the morning if the battery temps allow.


is the cold temp of the battery the reason the volts are so low? I'm assuming the heating pad drained the battery till the battery didn't not register the heating pad then the cold temps are driving the voltage super low.

What should I do in this situation?

 

[Bob B]

Well .... Either of your 2 choices seem about the same ..... just need to try to get some charge on it as soon as you can. Starting with slow charge would be a good idea to see if it recovers.
What is the battery temp?

 

[Stephen Shreds]

Well .... Either of your 2 choices seem about the same ..... just need to try to get some charge on it as soon as you can. Starting with slow charge would be a good idea to see if it recovers.
What is the battery temp?

I have no Idea. The temp switch to the heating pad was connected to the battery. I'm going to remove the battery tomorrow and put it in storage as that is a better way for me to heat the batteries.

 

[Sojourner1]

Can't speak to specific cold and low cell issues but the first thing I would do is get the cells warmed up. It won't take much, last month a couple cells of mine dropped below 30f and the balance were 33-34f. I have a small heater I can place in the front compartment to give quick heat and within an hour all cell temps rose to 50f. I can see all individual cell temps.
Putting your batteries in a running vehicle with heat blasting for an hour or so should warm the cells quickly. Get it hot in there.

Don't leave the cells depleted longer than you have to, put a slow and low charge on them. Maybe they aren't harmed yet but waiting longer isn't helping either.
Don't procrastinate.

 

[Stephen Shreds]

Don't leave the cells depleted longer than you have to, put a slow and low charge on them.

So i just removed the battery and put it in storage and that was a bitch to do. sooo many wires. i am going to buy more buss bars. my positive post is cross threaded for sure. i should have bought heated battle born batteries. how do you recommend i do a low and slow charge? i don't own a trickle charger and the only way for me to charge them right now is my renogy dc to dc charger.

 

[Sojourner1]

Not knowing what you have or using it would hard to say. If all you have is that dc-dc charger then thats the hand your dealt.

If it were me I would of warmed the cells immediately and put a charge on the cells but if your not relying on the batteries for day to day needs then I guess no worries.

 

[orangeminnie]

Does this battery have a BMS? If so, it's unlikely that you killed it. You're just in low-voltage disconnect and you should be OK if you get it charged back up soon.

 

[Pyke13]

If you have the cc/cv bench top power supply most seem to use to top balance use that. It should allow you to set the current down low to bring the soc up a bit, then turn it up as you get some charge into them

 

[Luthj]

The second that battery gets above 32F, start charging it, you need to get it above 10V ASAP. Once you are above 10V slow charge it to 14V or so. If you notice any bloating stop and evaluate.

If you are lucky the low temps reduced the damage to the SEI and current collectors.

Do you have a BMS? Because it sounds like you don't... If you don't have a BMS with disconnect ability, don't charge the cells above 12V until you do. Deep discharge like that can damage cells, and recharging without a BMS can result in one cell going overvoltage withou you noticing, which can be a fire risk.