Liitokala strikes again

[marksman]

Bought 8 LiFePO4 cells, supposedly 105 Ah from "Liitokala Battery Flagship Store". A Facebook solar group I follow had plenty "success stories" with that store so I placed the order.
The cells arrived. Two of them were a bit swollen, but not much. I tried to dismiss the fact, but contacted the seller anyway. Posted pictures of swollen batteries on the chat would not show up because of "inappropriate content". Sharing the pictures via Google Drive but seller said the access is denied even though I made the folder public. I ended up equalizing the batteries by connecting them in parallel, compressed, and attaching them to a benchtop power supply. All were holding the charge at 3.35 V, even the slightly swollen cells did seem to come back to shape.
The 24 V battery seemed all right, I hooked it up to the AIO EAsun/Powland inverter and started charging: charging voltage 27.6 V, float at 27.5 V and suddenly bam! Overvoltage protection. The overvoltage protection was set at 3.6V and one cell has reached it while the other cells were not even at 3.3V.
I tried to change the cell position but the issue would follow the cell. A second cell was off as well but not to this extent. Tried to cycle the cells completely, but while other cells were at 3.1xx V this cell would trigger the undervoltage protection at 2.6 V.
I tried to message the seller, they would not answer. Posted a follow-up review, nothing happened. I noticed my review was the only one standing, everything that was posted before,.good or bad was just gone.
So here I am, having a battery I can't use. I tried everything: - to have the inverter disconnect at maximum allowable voltage which is 24 V, that is 3 V per cell: no go, because at 25.1x V the bad cell is already at 2.6 V
- limit charging to 3.4 V per cell: would get overvoltage protection and get the BMS to pull the plug way early. I had to set it to 3.35 V per cell.

After reading almost everything Liitokala related on this forum I have to say that I've been duped: not only was I sent lower capacity cells (I knew they were not 105 Ah but rather 75-90-ish), but have been sent a 55-60 Ah cell, a 68-70 Ah cell and 6 "good" cells. How did I came to these numbers? Reset the cycle counter on the BMS, and used a A/C unit to pull 58-60 Ah from the battery. Got about 68 Ah Cycle capacity before the AC switched off due to Undervoltage protection.
I'm now facing a dilemma: scrap the somewhat good cells (I can probably build a nice 12 V battery for my father's off grid shed) and call it a loss, or buy a set of 4 cells and hopefully harvest 2 good cells to replace the faulty ones but give some more money to these crooks?
For the $390 I paid them I could have gotten two honest 100 Ah gel cells or I could have saved for 8 Elirix 100 Ah cells.

 

[v_green57]

25% failure rate.

Use them as doorstops.

It will (and should) always nag at you if you put the "good" cells to use anywhere. Your Dad deserves better.

 

[wholybee]

What you describe is EXACTLY what GOOD cells do if you don't top balance them before building a battery pack. So, until you do that, you have not shown the cells are bad.

No where in your post do you describe performing a top balance. Paralleling the batteries at ~3.35 volts will do nothing to help balance them. You need to charge them to 3.55 volts or more while they are in parallel, and leave them charging until the current drops to nearly zero. There are many threads on this forum describing how to properly top-balance. There is a specific procedure for it and if you don't follow the procedure you can damage the cells.

 

[Alkaline]

Littokala has a legendary reputation of being the biggest rip-offs in the world, so bad, even youtubers have exposed them:

 

[wholybee]

True, but the OP still needs to top-balance the cells to know if they are bad.

 

[Quattrohead]

I don't know why we are yelling at the op, it's quite obvious that he has bad cells there. Lesson learned.

 

[Zwy]

Bought 8 LiFePO4 cells, supposedly 105 Ah from "Liitokala Battery Flagship Store". A Facebook solar group I follow had plenty "success stories" with that store so I placed the order.
I ended up equalizing the batteries by connecting them in parallel, compressed, and attaching them to a benchtop power supply. All were holding the charge at 3.35 V, even the slightly swollen cells did seem to come back to shape.

Proper method of a top balance when dealing with questionable cells. I usually charge raw cells with a BMS to speed up the process until one cell in the pack gets close to 3.65V, then break the pack down and do the following.

All cells in parallel, charge using a CV power supply set to 3.65V. I recommend larger leads of 10AWG wire and use ring terminals and not alligator clamps to minimize any voltage drop. Cells are balanced when amperage drops to under 1 amp, preferably very close to 0 amps.

Only after you have done this can cells be considered top balanced. You may need to cycle cells several times to get a true assessment of the cells.

 

[wholybee]

I don't know why we are yelling at the op, it's quite obvious that he has bad cells there. Lesson learned.

The only thing in his post to suggest bad cells is that he purchased from an untrustworthy source. Nothing in his experience with them suggests a problem.

That is important, because if the OP now goes out an buys the most expensive grade A cells from a reputable source, he will have the same results if he doesn't learn how to top balance cells properly.

 

[Quattrohead]

Rubbish, cell number 7 is obviously faulty and cell number two does not look that great either.

 

[Zwy]

Rubbish, cell number 7 is obviously faulty and cell number two does not look that great either.

I'll take them all for free if he wants to ship them to me.

 

[time2roll]

Picture shows me a low cell at the top becomes the low cell at the bottom. That cell #7 in pic 1,2 needs a boost charge to match the others at the top. Possibly an active balancer can do the work over a couple weeks.

I have some Liitokala that are working fine. Did not do a top balance so it took some time for the balancer to work.

 

[wholybee]

Rubbish, cell number 7 is obviously faulty and cell number two does not look that great either.

I see 8 cells that are all way out of balance, with #7 and #2 being the lowest of the 8. A top balance will fix that. If after that it doesn't stay in balance, then an active balancer might be able to deal with it.

From what is shown, there is no indication of anything wrong except the cells are not balanced.

 

[Quattrohead]

The cells are not balanced because one of them is so fubar the balancer cannot get it back in line. If anyone thinks anything else they are delusional or a Chinese cell seller.

 

[marksman]

Hi, guys, thanks for commenting out, I appreciate all the feedback.

I did top balance to 3.5V by connecting them all in parallel and using a Chinese benchtop power supply. I had to leave them connected for almost three weeks for the current to reach (almost) zero. Guess the alligator clips didn't help.
After settling, the voltage was about 3.350 V on each cell. At that point I "un-parallelled" the cells and started to build the battery but the BMS was connected a week later due to lack of time. Voltage was way out, from 3.225 to 3.288. So that might have been a wrong move on my side but I thought the BMS would eventually balance them and it does, unless I start charging or discharging the pack:
- when charging, cell 7 would overshoot the others and trigger overvoltage protection (3.600V) and cell 2 would lag behind others about 0.05V
- when discharging, cell 7 would be the first to reach 2.7 V and trigger the undervoltage protection while the others, including cell 2, are still at 3.1xx

So yeah, my top balancing might not have been 100% accurate but cell 7 is way, way out of line. I can try to dismantle the battery and redo the top balancing but I have had my doubts on two of the cells ever since opening the package and seeing they were bloated. Not much, but visible to the naked eye even without aligning the cells.
Do you think it's worth dismantling the battery and re-doing the top balancing?

 

[time2roll]

No need to dismantle. Charge near the top and hold the voltage while the power supply tops up the low cell. Connect the power supply direct to that cell only after presetting to 3.500-3.650 to match the others.

 

[sunshine_eggo]

Hi, guys, thanks for commenting out, I appreciate all the feedback.

I did top balance to 3.5V by connecting them all in parallel and using a Chinese benchtop power supply. I had to leave them connected for almost three weeks for the current to reach (almost) zero. Guess the alligator clips didn't help.

Nope. they suck.

After settling, the voltage was about 3.350 V on each cell.

Settled for how long?

At that point I "un-parallelled" the cells and started to build the battery but the BMS was connected a week later due to lack of time. Voltage was way out, from 3.225 to 3.288.

Please confirm:
Charged to 3.50V and 0A
They settled to 3.35V in parallel.
They were un-paralleled
After sitting completely dormant for a week with no BMS connection and no parallel connection (series connection is fine), all cells dropped to 3.225-3.288

If yes, you have confirmed that all cells are bad. If only a handful of cells dropped to that level, then those were the bad cells. No cells should have been below 3.300V (likely higher than that, but I'm highly confident in that answer).

 

[marksman]

I started the process beginning of April and ended it in June. I first topped to 3.4 then to 3.5. Took about three weeks to reach 0 A until 3.4 but about a week to reach 3.5. Settled about 2 weeks, got 3.35. Then left un-parallelled for a week, got 3.225-3.288. I'm not really sure about this: might have been more than a week though. At the time I had quite a lot going on in my life so I could only work on the solar stuff for limited amounts of time.

No need to dismantle. Charge near the top and hold the voltage while the power supply tops up the low cell. Connect the power supply direct to that cell only after presetting to 3.500-3.650 to match the others.

So if I get this right the steps would be:
- disconnect the battery from the system
- disconnect the BMS from the battery
- charge each cell individually to 3.5-3.6V
- reconnect the BMS
- reconnect the battery.

 

[sunshine_eggo]

I started the process beginning of April and ended it in June. I first topped to 3.4 then to 3.5. Took about three weeks to reach 0 A until 3.4 but about a week to reach 3.5. Settled about 2 weeks, got 3.35. Then left un-parallelled for a week, got 3.225-3.288. I'm not really sure about this: might have been more than a week though. At the time I had quite a lot going on in my life so I could only work on the solar stuff for limited amounts of time.

I have CALB cells that have sat for over a YEAR and are above 3.300V and retain 90% of their stored energy.

Again, if those cells sat unparalleled for a week or more, and not connected to a BMS or anything that MIGHT cause a drain, AND they were all sitting at 3.225-3.288, they are all horribly, horribly bad cells. They are beyond saving.

 

[time2roll]

I started the process beginning of April and ended it in June. I first topped to 3.4 then to 3.5. Took about three weeks to reach 0 A until 3.4 but about a week to reach 3.5. Settled about 2 weeks, got 3.35. Then left un-parallelled for a week, got 3.225-3.288. I'm not really sure about this: might have been more than a week though. At the time I had quite a lot going on in my life so I could only work on the solar stuff for limited amounts of time.

So if I get this right the steps would be:
- disconnect the battery from the system
- disconnect the BMS from the battery
- charge each cell individually to 3.5-3.6V
- reconnect the BMS
- reconnect the battery.

More like this:

Leave everything connected
Use the system to charge the battery until the top cell is 3.500 to 3.650 volts
At the same time charge that low cell with the power supply pre set to 3.650 volts
When the low cell matches with the high cell remove the power supply. BMS connected is the best way to monitor the progress.
Back in service

 

[wholybee]

Hi, guys, thanks for commenting out, I appreciate all the feedback.

I did top balance to 3.5V by connecting them all in parallel and using a Chinese benchtop power supply. I had to leave them connected for almost three weeks for the current to reach (almost) zero. Guess the alligator clips didn't help.
After settling, the voltage was about 3.350 V on each cell. At that point I "un-parallelled" the cells and started to build the battery but the BMS was connected a week later due to lack of time. Voltage was way out, from 3.225 to 3.288. So that might have been a wrong move on my side but I thought the BMS would eventually balance them and it does, unless I start charging or discharging the pack:
- when charging, cell 7 would overshoot the others and trigger overvoltage protection (3.600V) and cell 2 would lag behind others about 0.05V
- when discharging, cell 7 would be the first to reach 2.7 V and trigger the undervoltage protection while the others, including cell 2, are still at 3.1xx

So yeah, my top balancing might not have been 100% accurate but cell 7 is way, way out of line. I can try to dismantle the battery and redo the top balancing but I have had my doubts on two of the cells ever since opening the package and seeing they were bloated. Not much, but visible to the naked eye even without aligning the cells.
Do you think it's worth dismantling the battery and re-doing the top balancing?

If you did that then it sounds like *all* the cells are bad with a high self discharge rate.