Watching it now - appreciate you sharing it.
@mariocontino well the video is not ambiguous at all, and leaves little room for “maybe this is ok”. Gotta say I agree with you.
I didn’t before, but after your frothy and inappropriate tantrum, I gave it a look. Quite good and a great explanation!
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Quick saga update. Battery will not charge to full, and is pretty badly unbalanced, so obviously this is not a healthy battery. I have taken all the battery experts’ advice and let the seller know I will need to replace the battery because the full depletion has basically ruined it. Going to ask him to pay for a replacement battery.
It sucks for him, but the truth is the board should have been packed so that there was no way it could turn on in shipping and destroy the battery.
Thank you @Battery_Mooch @TheBoardGarage @BillGordon @Evwan @Nordle
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Props for making the hard choice. Sorry you have to deal with this.
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Well, yea.
It makes me very popular.
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It happens. Unfortunately, more often than it should.
Almost half of the batteries I built in the shop this spring were dead pack replacements, mostly from winter storage.
That Naz can house a 12s5p easily. Should be a nice bit, I’ve done a couple. And my Proto does nicely with a freshie 12s5p.
It sucks now, but you’re better off anyway. Cheers, best of luck.
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Maybe a video on how to properly store batteries over the winter?
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Current battery status after a “full” charge, 49.14v and 100mv imbalance.
I just sent an email to Lacroix to get their advice.
This isn’t convenient but it can help you determine if some cells might be damaged…
- Let everything sit for two hours (no charging or use) and then write down all the cell voltages.
- Unplug everything from the pack and let the pack sit for as long as you can, a week is good.
- Reconnect everything and measure the cell voltages again.
- If one or more p-groups have dropped a decent amount more than the others then they might have one or more damaged cells in them.
All the p-groups staying close to their original voltages does NOT mean the pack is undamaged! It would just mean the cells haven’t been damaged in a way that speeds up their self-discharge.
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@TheBoardGarage If I was going to put a new battery in it, I think it would be a 12s6p of 20700 cells. That’s what this enclosure was originally designed for.
Slightly more expensive than p42a’s but you get an extra P with 20700, and 50mah more capacity.
Sanyo NCR20700B 4250mAh 15A Battery (imrbatteries.com)
I haven’t resolved anything with the seller yet, so this is all hypothetical for now.
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@Battery_Mooch I appreciate the good advice, but it seems like things are going downhill. It is self discharging and becoming increasingly unbalanced.
This is 2.5 hours after giving the board a full charge and not touching it.
It’s been a hot minute since i saw someone use Sanyo cells.
There’s no good reason to use the Sanyo’s unless your enclosure demands it.
The flex on this Lacroix deck is something magical btw. I was not expecting it to be so flexy.
Whoa…#6 dropped 44mV in two hours even after resting the pack for two hours before that? And nothing, absolutely nothing, was connected to the pack…no BMS?
If so, then yea, IMO the pack is damaged.
Sorry if I was unclear, the BMS is still attached, but the stock configuration for these boards is balance only when charging, so there is no balancing going on. There is some small amount of load from the BMS bluetooth.
That reading is just 2.5 hours after taking the board off the charger and not touching it in any way. No opening up and disconnecting things.
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That test really need to be done with absolutely nothing connected. It can be very inconvenient to do though and often not possible. Otherwise we can’t know what was self-discharge and what is due to the quiescent current draw of any connected electronics.
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Yeah that makes sense. I was wrong to use the term self discharge with that screenshot.
What I really meant is that the battery is clearly not behaving like a healthy battery.
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@TheBoardGarage you were 100% right. Recharging the dead battery was a bad idea. I wish I didn’t even do it in the first place. The battery was fully charged (49.2v max) yesterday and has been sitting untouched since then. As you can see, things are not great.
Do you think there a point that this battery would become a fire risk due to unbalanced cells?
I’m assuming it would be a very bad idea to turn the board on or charge it in its current state?
@Battery_Mooch appreciate any thoughts you have here too.
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You should find a place to safely recycle that battery pack. No more answers from the experts are really necessary at this point, my man. You know what you need to do.
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Yeah I’m 100% not asking for a blessing to do anything stupid like continuing to use it.
Moreso trying to learn about battery failure and assess the level of danger a pack may present while sitting unused.
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