forscience
New Member
- Joined
- Dec 13, 2021
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- 30
That is bad.However, one of them is only at 0.9V when I measured them. Is that cell permanently damaged or can I try to top balance it with the other cells and it'll be ok?
No cells are bloated and I do not smell anything. The measurement for each cell were: 3.4V, 3.4V, 3.3V, 0.9V.That is bad.
Don't try to charge yet, especially don't attempt a parallel top balance.
Are any of the cells bloated?
Are all the vents intact?
Do you smell or see any electrolyte?
The electrolyte is toxic so if you see or smell electrolyte get your ppe on and get the cells out of your living space.
I suggest you charge the low cell individually at low current ~1 amp until it gets up to ~2.8 volts.No cells are bloated and I do not smell anything. The measurement for each cell were: 3.4V, 3.4V, 3.3V, 0.9V.
Yes, they are advertised as new grade A cells. My DC power supply is rated for 10A max and each cell is rated for 100Ah.I suggest you charge the low cell individually at low current ~1 amp until it gets up to ~2.8 volts.
Then you can increase the current.
How many amps is your benchtop power supply rated for.
The fact that 2 cells are 3.4 volts and one is 3.3 is not a good sine either.
Were these cells advertised as brand new grade A?
The reason I advise you to charge them individually is the low one could "dead short" and take the other cells in parallel to hell with it.
@sunshine_eggo
Probably not salvageable but its worth a try.Yes, they are advertised as new grade A cells. My DC power supply is rated for 10A max and each cell is rated for 100Ah.
1) so you think that the 0.9V cell is still salvageable by charging it alone? Will it's capacity be reduced having sat at such a low voltage?
I suggest charging each cell individually to 3.65 volts.2) If I do charge the 0.9V cell up to 2.8V, can I then top balance it along with the other 3 cells?
Yes I would worry.2) The voltage window for these cells in the description is 2.3 - 3.65 V. So do I need to worry about the difference between the 3.4V and 3.3V cells? Will there be any issues if I went ahead and top balanced them?(assuming the 0.9V cell is at 3.4V or 3.3V)
Yes all 4 cell individually.3) by advising to charge them individually, do you mean charge all 4 cells individually? or just the 0.9V cell prior to top balancing all 4 together?
Here's the listing(https://www.ebay.com/itm/115016791435). I guess it doesn't say "New", but the price I think is on the cheaper end($100 per cell) so if that's worth it for a cell with 3.4V still then I'm ok with it. So why would a 3.4V cell be bad quality? This is my first time buying a lithium battery.Probably not salvageable but its worth a try.
I suggest charging each cell individually to 3.65 volts.
That is functionally equivalent to a parallel top balance.
If it was me I would let them sit for a month to see how much each one settles.
Yes I would worry.
I these were advertised as grade a brand new cells you have been ripped off.
Even the commodity A- cells arrive 3.295-3.3 volts.
Yes all 4 cell individually.
You didn't answer my question about whether these cells were sold to you as brand new grade a cells.
If it was me I would try to get my money back.
1 or more of your cells are very likely crap.
Possibly all of them.
As I said before new cells typically arrive at 3.295-3.3 volts.So why would a 3.4V cell be bad quality?
Further to that...As I said before new cells typically arrive at 3.295-3.3 volts.
Since 2 of your cells arrived at a voltage at least 100mv higher than "shipping" voltage, I suspect they are returns.
Is full resting voltage at 3.4 volts ok? I'm just wondering if it's worth trying to return given the $100 per cell price. At the moment, I plan to return the 0.9V cell.Further to that...
3.4 volts is pretty close to full resting voltage.
Full cycle for an lfp cell is 2.5-3.65 volts.
3.4 is ok.Is full resting voltage at 3.4 volts ok?
The fact that they sent you 1 cell way below dead empty and 2 that are probably full is not good.I'm just wondering if it's worth trying to return given the $100 per cell price. At the moment, I plan to return the 0.9V cell.
Thanks for your help, I learned quite a bit. I will just return the 0.9V one.3.4 is ok.
The problem is you don't know how long those cells have sat full.
Its less than ideal to leave a cell full for extended periods.
The fact that they sent you 1 cell way below dead empty and 2 that are probably full is not good.
The vendor probably won't see it that way though.
Possibly because they don't know what they are doing or they don't care.