FYI........... Do So At Your Own Risk

Spoc85

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For the Lads that are not too fond of the hazards that come with Lipo batteries........... this thread is probably not for you.

I gave the Lipo a quick hit on the NiCd setting for a couple minutes. This brought the voltage up but it would continue to drop once off the charger. I then gave it a boot full, over an hours worth. Once off the charger it held Voltage but now I had issues with the other 5 cells sitting at near 4.6v. I identified the cell with the issue, isolated it from the rest and used a 12v pump and 2 Led lights to shedd the load. That 12v pump has never spun so fast. I got them pretty close initially and thought I could balance the cells out once back on the charger but they wouldn’t equal out. Continued to shed load to where they were all near dead on, threw the Lipo back on balance charging......... Happy days!!

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This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
 

Spoc85

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This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
After giving all 6 cells a hit on the NiCd to raise the volts on the damaged cell, I now had 5 cells at 4.6V and 1 at 3.85. I hooked the pump and the lights to those 5 cells (20v) to bring the voltage back down to the damaged cell that was left alone at 3.85V. Once I had all 6 cells fairly close I then put it back onto the charger and balanced them out on the Lipo setting.
 

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For the Lads that are not too fond of the hazards that come with Lipo batteries........... this thread is probably not for you.

I gave the Lipo a quick hit on the NiCd setting for a couple minutes. This brought the voltage up but it would continue to drop once off the charger. I then gave it a boot full, over an hours worth. Once off the charger it held Voltage but now I had issues with the other 5 cells sitting at near 4.6v. I identified the cell with the issue, isolated it from the rest and used a 12v pump and 2 Led lights to shedd the load. That 12v pump has never spun so fast. I got them pretty close initially and thought I could balance the cells out once back on the charger but they wouldn’t equal out. Continued to shed load to where they were all near dead on, threw the Lipo back on balance charging......... Happy days!!


View attachment 150481
If you were trying to revive a LiPo because it is under-voltage and the charger doesn't charge it, I have personally had the same problem. I researched and found an article the covered this [roblem. You need to change it on the NiMh setting. The charger should work fine. But never leave it alone, unsupervised.
 

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This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
This is awesome! I’ve done my fair share of the ole NiCd trick, I’ve also had a 6 cell get all hot and Smokey so I cut her open and did some surgery real quick separating the bad cell from the others then amputating it. Now I have a pretty nice little 5cell from goldbat(I attempted multiple times at filing a warrantee claim never got no response from nobody despite going 4 different avenues of communication)
Anyways you say 5 cells were at 4.6v per cell and 1 was stuck at zero, you hooked it up to the pump and leds, that somehow brought that 1 dead cell volts up? How’s that work?
Can you please repeat one more time? Didn't quite get it the first time or the second time. But I almost got it the third time. Lol....
 

Spoc85

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If you were trying to revive a LiPo because it is under-voltage and the charger doesn't charge it, I have personally had the same problem. I researched and found an article the covered this [roblem. You need to change it on the NiMh setting. The charger should work fine. But never leave it alone, unsupervised.
I was going back and forth between both NiMH and NiCd settings.
 

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Had to do this once, put charger in nimh mode until lipo got to 3.0V per cell then switched to lipo mode and it fully charged. Probably killed some life but still use it today.
 

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Had to do this once, put charger in nimh mode until lipo got to 3.0V per cell then switched to lipo mode and it fully charged. Probably killed some life but still use it today.
Is charging a lipo that way dangerous? Or is it OK just to get the voltage up high enough to charge it in lipo mode? I have one battery that the voltage is too low for lipo mode and won't charge. Voltage is low cause I mistakenly let my fans run to cool motor and ESC after it hit LVC and now it won't charge back up.
 

Spoc85

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Had to do this once, put charger in nimh mode until lipo got to 3.0V per cell then switched to lipo mode and it fully charged. Probably killed some life but still use it today.
The issue I had in this case was I couldn’t get the bad cell to reach the same voltage as the other 5 after charging on the NiCd for over an hour. It was out by nearly a volt. Doesn’t sound like much but once in service the car would suck the life out of the weak cell first, sending the car into LVC with in a matter of minutes.
 

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The NiCd/NiMH settings simply disable the voltage reporting back to the charger, it's not magic. Do this at very low current settings only, the Lipo's generate an insane amount of heat below 3V when charging.
All cells are now damaged. I bet the IR is horrendous on the one cell when compared to the others.
A better way is to monitor all cell voltages and as soon as the 'bad' cell crosses 3.3-3.4V you switch the charger back to Lipo mode. It avoids the danger of overcharging and damaging the other cells, which is the main reason the Nixx mode can blow up your cells.
At 4.6V you were just lucky they didn't go up in flames. Your charger is only capable of 50W and that might have saved you from a fire.

Other than that, it's a perfectly ok way to try and revive a Lipo. Key is to keep an eye on ALL cells and keep the current at minimal values until all cells are in a safe range.
 

Spoc85

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The NiCd/NiMH settings simply disable the voltage reporting back to the charger, it's not magic. Do this at very low current settings only, the Lipo's generate an insane amount of heat below 3V when charging.
All cells are now damaged. I bet the IR is horrendous on the one cell when compared to the others.
A better way is to monitor all cell voltages and as soon as the 'bad' cell crosses 3.3-3.4V you switch the charger back to Lipo mode. It avoids the danger of overcharging and damaging the other cells, which is the main reason the Nixx mode can blow up your cells.
At 4.6V you were just lucky they didn't go up in flames. Your charger is only capable of 50W and that might have saved you from a fire.

Other than that, it's a perfectly ok way to try and revive a Lipo. Key is to keep an eye on ALL cells and keep the current at minimal values until all cells are in a safe range.
She’s not far off.
Like I said there are hazards that come along with this method to rectify a damaged Lipo but if adequate controls are put in place......... nobody Is going to die from implementing this procedure.

E893D913-32CF-482C-9666-A79129C20D20.jpeg
 

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Is charging a lipo that way dangerous? Or is it OK just to get the voltage up high enough to charge it in lipo mode? I have one battery that the voltage is too low for lipo mode and won't charge. Voltage is low cause I mistakenly let my fans run to cool motor and ESC after it hit LVC and now it won't charge back up.
I don't think it's dangerous, I do it outside. It was a 3 cell pack at about 2.65 or so volts per cell. Took just a few minutes to get the cells to 3.0 volts per cell and that was enough to get lipo mode going. Charged fully and balanced. Try it, it's works and will save the pack.
 

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I don't think it's dangerous, I do it outside. It was a 3 cell pack at about 2.65 or so volts per cell. Took just a few minutes to get the cells to 3.0 volts per cell and that was enough to get lipo mode going. Charged fully and balanced. Try it, it's works and will save the pack.
That's cool. Thanks. I'm gonna try it.
 

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I have a 3S pack that has been in storage for a couple of weeks, but now it doesn't charge because 1 cell is now at 1.5V. The other two cells are OK

Is that single cell too low to try the NiMH trick? I am interested to try it if can save the pack, but I'll follow the AF experts if they think the pack is dead. I think it doesn't look good if the voltage of one cell is so far from the two other.

Thoughts?
 

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Why do all this difficult stuff?

Take another lipo and plug them both on a balance board. hold your hand on the bad cell connector and pull it out if the gets too hot (and it will)
3x 10s burst often is enough to bring the low cell back into charging range.

To bring the cells back to balance, i have chargers that don't require a main lead, so i can just make charge one cell disregarding balance protocols.
 

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Why do this? Again, do it all at your own risk.
You have no control over the charge current when plugging it in parallel, even a good Lipo will be at risk if the cells are significantly different.

Using a charger and a low charge current, while monitoring the cell voltages, is guaranteed to work with minimal to no risk.
Plug it in parallel, and you might end up with 2 bad Lipos.
 

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The NiCd/NiMH settings simply disable the voltage reporting back to the charger, it's not magic. Do this at very low current settings only, the Lipo's generate an insane amount of heat below 3V when charging.
All cells are now damaged. I bet the IR is horrendous on the one cell when compared to the others.
A better way is to monitor all cell voltages and as soon as the 'bad' cell crosses 3.3-3.4V you switch the charger back to Lipo mode. It avoids the danger of overcharging and damaging the other cells, which is the main reason the Nixx mode can blow up your cells.
At 4.6V you were just lucky they didn't go up in flames. Your charger is only capable of 50W and that might have saved you from a fire.

Other than that, it's a perfectly ok way to try and revive a Lipo. Key is to keep an eye on ALL cells and keep the current at minimal values until all cells are in a safe range.
This is exactly what I was thinking as I was reading this. I bet IR is through the roof on those cells. I would not use that LiPo for heavy duty amperage draws. Technically I wouldnt use it at all but thats just me. If I was going to attempt this sort of thing at all I would have used a stand alone blancer like an astro blinky and at least let it bleed off the over charge to the functioning cells then once the bad cell is at least 2.8V/C then switch it back over to lipo charging. The best thing to do if you wanted to do something risky is disect the lipo and extract the bad cell and just change the pack to a 5S or a 4S pack (Not sure if it was 5 or 6S to start with).

I have a 3S pack that has been in storage for a couple of weeks, but now it doesn't charge because 1 cell is now at 1.5V. The other two cells are OK

Is that single cell too low to try the NiMH trick? I am interested to try it if can save the pack, but I'll follow the AF experts if they think the pack is dead. I think it doesn't look good if the voltage of one cell is so far from the two other.

Thoughts?
IMO that is too low. Once the cell has gone under about 2.6V the cell becomes damaged and has a much higher IR than the other cells in the pack. This creates a fire hazard. If you have ways to measure the IR of your cells then you can try it and hope the IR isnt to far off the other cells but even then you'd need to take the IR of the highest cell and use that plus the batteries FoM to determine the new lower C rating of the pack.

Most people have neither the knowledge or the tools to properly address these sorts of issues with LiPos. You can do whatever you like but youre just making it a risky battery to use after that. Maybe you'll get lucky...maybe you wont.
 
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At quick answers i sometimes forget to give some context.
I didn't state the obvious that i would only do my balance trick with smaller lipo's for low amp applications. Like my signal booster battery, that i forget to unplug often enough.
Pumping cells to 4.7V slow or not, is more dangerous in my book.

If one of my speed run packs had a bad cell it they will never deliver the amps i need again, so there it's definitely no option
 

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At quick answers i sometimes forget to give some context.
I didn't state the obvious that i would only do my balance trick with smaller lipo's for low amp applications. Like my signal booster battery, that i forget to unplug often enough.
Pumping cells to 4.7V slow or not, is more dangerous in my book.

If one of my speed run packs had a bad cell it they will never deliver the amps i need again, so there it's definitely no option
I agree with that. Ive done the ressurection trick too but I have ESR meter, spot welder, good soldering skills, wire, and JST-XH connectors to repair or even rebuild packs if need be. Definitely a whole lot less critical with smaller low amp draw batteries. Im with you though, Anything that sees high current use I would not use again once even one cell jumps up in IR compared to the other cells, even by just 5 or 10 milliohms.
 

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Agreed, heck NO on charging above 4.2V, the 4.7V is insanely dangerous and surprised it didn't catch fire.
That is why you monitor all cells and stop this charging until the 'bad' cell is above the 3V-3.3V that the charger needs to recognize it as a Lipo.
If it never reached that level with the other cells going towards 4.2V you simply cut your losses.
 
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