Still good/ safe to use?

[dawgleader1]

Hey all,




Call me stupid, and very busy, but mainly stupid. I purchased 2 10kwh LiFe PO4 'powerwalls' from GSL Energy back in 2020. At the time, I rushed to buy a bunch of stuff due to the global 'emergency' going on at the time and uncertainty around that. I mounted them to the wall in a clean garage but never got around to connecting them to any power source or inverter. They have hung there unused for the past 5ish years. Are they still safe/ good to use. I'd like to finally finish my project that I never got around to finishing. I'm hoping I didn't flush all that money down the toilet...




Any advice is appreciated. Thank you.

[SunEagle]

You should check their voltage and if they are in the manufactures range they should be ok to use. Good luck and et us know how you made out

[dawgleader1]

Hi SunEagle, Thanks for the response. I just got a chance to check the voltage as you requested. I have 2 of these powerwalls. For the first one it looks promising. I attached the photos below for your review. When I tried to turn it on, I was surprised that it powered up immediately since it's never been turned on for the past 5 years. It looked like it had quite a bit of charge and that the voltage was reading very good. The way it looks to me, and I'm ignorant with these things, it looks like it would be safe and usable as it is. Since I got 4 green lights on capacity with a 49.36 voltage reading on the bms, which I confirmed with my voltmeter, I would think this one powerwall would be good to go. Is that a safe assumption?

[dawgleader1]

However, the news for the other powerwall isn't nearly as good. Looking at it, it's probably fried. When I turned it on, which it did come on right away, which was good, I got completely different readings on the screen. Pictures are attached. I don't know if it can be 'saved' or not. I did have the 2 powerwalls connected together, don't know if that was a good thing which may have saved the first one, or a bad thing which may have killed this one. I have one other picture I'll do in my next post which confounds me.

[dawgleader1]

As you can see, in the pictures above, for the 2nd/ 'dead' powerwall, it's not showing any capacity, and the voltage reads 0 on the screen and .5 on my voltmeter. So, I was VERY surprised that it even turned on. As I was testing it and taking pictures, the screen changed, showed a voltage of 17.75, the red alert light came on, and then it powered down. I didn't have any chance to retest it with my voltmeter since it powered down so fast. I don't know if that's normal of an empty battery or more indicative of a damaged battery pack. Or once again, if it can be saved. Let me know your analysis, and any suggestions: If the 1st one is safe and good to use, and the 2nd is dead and dangerous as I'm suspecting is the case on them. Or if I'm SOL on both for some reason. Or if the 2nd one can be recharged and saved, safely. Once again, thanks so much for the help. You're the only one that chimed up, lol.

[SunEagle]

I would use the good one and say goodbye to the bad one. Once a battery goes to 0 volts it may never be good again

[dawgleader1]

I am strongly leaning toward what you're saying. HOWEVER, if I wanted to try to charge up the 2nd one since it did turn on and gave me some sort of flash reading at 17v before shutting down. Would that be super dangerous? Could it explode? Catch fire? Or would it just not charge? From what I understand, these LiFe Po4 battery packs are supposed to be pretty damn safe and stable. But I do realize what I'm talking about is a special case situation. I don't want to blow myself up, burn my house or shed down, or cause a meltdown, but I don't want to throw it away if it can be saved. Even if it's at half capacity or something, that's still 5kwh of storage, as long as it's safe. And if you would think it would be safe to try to save it, what would be the best and safest way to do that? Plug it into a small solar panel array is what I'd think. Or I could plug it into the regular 120v ac outlet to my house, but that seems more iffy. If your suggestion is to trash the 2nd, 'bad' on for safety sake, I'll go with that just to be on the safe side. But, as I said, I'd love to save it if at all possible. Thanks again.

[SunEagle]

Any Li chemistry battery has the potential of starting a fire. If you choose to try to revive it I would not do so without fire mitigation or watching it closely

[dawgleader1]

After your post I did some googling and came up with the same conclusion you had, it's super dangerous to try to charge a LiPo that's been drawn to a true 0v due to the batteries probably have been damage. So, I am going to go with your recommendation and chalk up the 1 powerwall to a loss due to my stupidity. That unfortunate loss I can accept, it's not the first in my life. To try to recharge it and risk a fire or worse could potentially change a moderate stupid loss to a catastrophic loss by burning down my house or hurting someone. That's not worth it. I'm going to try to save the first one, the one that gave me a voltage reading or 49v. I think that one looks pretty safe to use. I'm actually happy to be able to save one of them considering that I originally figured I had wasted both of them.

I really appreciate your help and advise. If you have any other ideas or suggestions, please shoow them over.

PS. What's the best way to dispose of the one dead powerwall????

[dawgleader1]

Thinking about it more, an idea had crossed my mind, that maybe I could get some new cells and replace them since all of the other components are basically brand new, never used. I don't know how much the cells would cost to replace but I'm sure quite a bit less than trying to buy a whole new 10kwh batter bank these days. I'm going to do some research when I get a chance to see where I can source the cells from and how much it would run me. At least in that case it wouldn't be a complete write off. Maybe I can make myself feel better about the whole thing. lol.

[SunEagle]

I don't know what cells cost but i agree with you that replacing them should be cheaper then a new Powerwall

[chrisski]

If you open this up, you’ll likely see a 200 amp cell or combination in parallel to make this.

There can be a bit of work to do this if you can’t get same size replacement. I bought my 280 ah lithium cells 5 years ago and they’re still available.

if it’s easy to disassemble, then you can test what cells look good, or just start with new ones.

For me testing cells is a week long process. I only have a single 10 amp power supply for top balance and a single 20 amp capacity tester. Might actually take two weeks.