Help, Enerdel 12S pack fully depleted

tome

100 mW
Joined
Aug 11, 2012
Messages
40
I have an Enerdel 12S pack I bought from forum member Major a year or two back. It has been a great battery! Over the summer I stupidly left my two Celllog 8S's plugged in. The battery is totally drained. The cells are reading less than 0.5V on my Thunder 1220 that I have been using to recharge this battery. When I plugged that in and push/hold the charge button it brought up the charge screen and showed 4.xx V, and then began to slowly slowly climb. If I push the button again, it errors with low voltage.

I am not sure what to do, but I figured I would plug it in and start the charge cycle (one push/hold of the button) and see if it will slowly charge. It has been plugged in for about 30-40 minutes and is now up to 5.96V and slowly increasing. Will this work if I leave it plugged in for a long time? Is there anything else I can do to recover the battery?

-Tom
 
Bummer. I had a contactor stick on in my yard tractor and drain two 12S2P modules flat essentially to zero volts. I put a power supply on them at about 4A per cell. I did this outside and kept close watch. To my surprise they appear O.K. Been using them for several months. I did manually balance 2 cells which were about 200mV high. I continue to watch it, but I don't notice any ill effects. Be careful with it.
major
 
major said:
Bummer. I had a contactor stick on in my yard tractor and drain two 12S2P modules flat essentially to zero volts. I put a power supply on them at about 4A per cell. I did this outside and kept close watch. To my surprise they appear O.K. Been using them for several months. I did manually balance 2 cells which were about 200mV high. I continue to watch it, but I don't notice any ill effects. Be careful with it.
major

Thanks. Do you know if there is a way I can get my Thunder 1220 to ignore the low voltage and charge at, say 6A? I assume by 4A per cell you are talking about the "2P" and so about 8A ? at what voltage?
-Tom
 
Well, there is a NiMh manual mode that allows setting the current. I set it to 8A and pushed go. It is outside and I am watching (with my fire extinguisher in hand)....
-Tom
 
Still here, still charging, and no fire yet! Actually they aren't even a bit warm. The charger says the pack is at 35.5 V and pulling about 6.5A. The (damned) Celllogs are showing that the cells are still quite balanced.

2.953
2.984
2.974
2.967
2.976
2.978
2.967
2.963
2.962
2.976
2.970
2.970

None are charging faster than others. I am holding out hope that I got lucky too and the pack will recover....
-Tom
 
Got to 38V and decided to put it on the normal LiPo balance charge program to 4.2V/cell. This gets the balance connectors onto the charger so I can watch cell voltage and IR from the charger. IR looks good on all the cells and all are tracking quite closely. Everything seems normal so far...
-Tom
 
Please note, even though it does not flame up right away, there is a good chance it will happen someday. Especially at the end of charge, when battery is all nice and warm, full of fresh energy to release.
Overdischarged batteries should not be recharged. Especially LiPO/Li-ion, but applicable to LiFePO4 as well.
 
circuit said:
Please note, even though it does not flame up right away, there is a good chance it will happen someday. Especially at the end of charge, when battery is all nice and warm, full of fresh energy to release.
Overdischarged batteries should not be recharged. Especially LiPO/Li-ion, but applicable to LiFePO4 as well.

I didn't have time to charge to 4.2V on Saturday so I left them until today. They were at the charge state I left them, no observable discharge. I am continuing to bring the cells up to 4.2 and will run the go-kart and see how they behave when they discharge. So far they are still charging up and also staying balanced. The IR on each cell as read by the charger is quite good.

Circuit,
Do you have some direct experience with this, or some research papers you can point me to? Also note, these cells are none of the chemistries you cite. They are Lithium NMC with Hard Carbon (not graphite) anodes.

Thanks,
-Tom
 
I do not really know how Li-NMC cells are affected by overdischarge.
However I have observed high self-discharge on LIYUAN, no-name LiFePO4 cells, A123 cells and various LiCo cells. I have also witnessed a LiCo fire after attempted re-charge from overdischarged state.
Unless someone here will confirm that NMC is totally safe (which I don't think), I would suggest to do a proper self-discharge test:
1. discharge it at 1C or whatever to "empty" (lowers allowed) voltage.
2. again discharge it at 0.05C until it really settles at low voltage.
3. leave it for 2 weeks.
4. Compare all cells for differences, because most likely not all will be the same.
 
circuit said:
Overdischarged batteries should not be recharged. Especially LiPO/Li-ion, but applicable to LiFePO4 as well.

Sound , safe, advice...but The problem with this is, unless you know the FULL history of every cell/battery you own , you have no idea if they have ever been "overdischarged". ( think ..Hobby king !)
even packs you have owned from new, may have odd cells that have been discharged way down to near zero, but not noticed because other series cells have "disguised" their state until recharged.
i suspect most laptop packs have some cells that have been "overdischarged" at some time....despite supposed BMS systems...and boosted back into life again.
 
Hillhater said:
circuit said:
Overdischarged batteries should not be recharged. Especially LiPO/Li-ion, but applicable to LiFePO4 as well.

Sound , safe, advice...but The problem with this is, unless you know the FULL history of every cell/battery you own , you have no idea if they have ever been "overdischarged". ( think ..Hobby king !)
even packs you have owned from new, may have odd cells that have been discharged way down to near zero, but not noticed because other series cells have "disguised" their state until recharged.
i suspect most laptop packs have some cells that have been "overdischarged" at some time....despite supposed BMS systems...and boosted back into life again.
I never use a battery pack without BMS, so I am sure of the history. I also never use HK junk, only 18650 from trusted supplier. Laptops do have a BMS and that BMS has a "permanent fault" flag in case of overdischarge. Try to discharge you battery fully and leve it be for several months - it will overdischarge eventually and you will not be able to recharge.

Only DIYers can think of recharging dead cells, or use HK junk for EVs...
 
circuit said:
.....Try to discharge you battery fully and leve it be for several months - it will overdischarge eventually and you will not be able to recharge...
:?: :?: you are not reading many of the threads on here , are you !

circuit said:
...Only DIYers can think of recharging dead cells, or use HK junk for EVs...

:shock: You do realise you have just described 90% of ES members ! :lol:
 
Oh, I know you, you are the one spreading all kinds of opinions with confident face, making them sound true...

Hillhater said:
circuit said:
.....Try to discharge you battery fully and leve it be for several months - it will overdischarge eventually and you will not be able to recharge...
:?: :?: you are not reading many of the threads on here , are you !
I think I read enough. I was even tracking and documenting lithium fires from these and other forums and media, to determine what kind of chemistries or (non)BMSes are at fault. What I discovered was that all chemistries burn very well and most often user is the one to point fingers at. I did that in order to know more about this issue to improve our product. Yes, my company is making batteries and BMSes for 5 years now.
But is reading here somehow related to what is true or false? Please explain what you mean.

Hillhater said:
circuit said:
...Only DIYers can think of recharging dead cells, or use HK junk for EVs...
:shock: You do realise you have just described 90% of ES members ! :lol:
These numbers seem correct. So yes, I do realize what I am saying. Not very politically correct, I know. But that does not change the fact that most DIYers create problems for them self and others, where they could be easily avoided, if quality information was available. When there are so many different opinions, it is very hard to distinguish cherry from sh.... So please don't give advises where all you have is a firm opinion.
 
Interesting post, be curious to see how this works out in the long term! Best of luck! :D
 
Scottydog said:
Interesting post, be curious to see how this works out in the long term! Best of luck! :D

Well, how's this for a timely followup? ;)

This Enerdel 2P12S pack is still going strong (8+ years on). I have been using it off and on in the go-kart since this incident and have never had an issue with it. It has been sitting unused and uncharged for the last 1.5 to 2 years and I pulled it out yesterday to check and recharge/balance it for continued storage. I charged/balanced it to 3.5V/cell to store it last time (every cell was between 3.500 and 3.510) and was shocked when I hooked it up yesterday that every cell is still between 3.485 and 3.498 V!

Would be interesting to test the pack's overall capacity, though I didn't measure it when I got it so don't really have a benchmark.

-Tom
 
glad to here your batterys in good shape, these forums are full of good advice and BS in equal proportions
 
tome said:
Scottydog said:
Interesting post, be curious to see how this works out in the long term! Best of luck! :D

Well, how's this for a timely followup? ;)

This Enerdel 2P12S pack is still going strong (8+ years on). I have been using it off and on in the go-kart since this incident and have never had an issue with it. It has been sitting unused and uncharged for the last 1.5 to 2 years and I pulled it out yesterday to check and recharge/balance it for continued storage. I charged/balanced it to 3.5V/cell to store it last time (every cell was between 3.500 and 3.510) and was shocked when I hooked it up yesterday that every cell is still between 3.485 and 3.498 V!

Would be interesting to test the pack's overall capacity, though I didn't measure it when I got it so don't really have a benchmark.

-Tom

Wow sorry read this a bit late!! :D
 
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