Liitokala strikes again
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LakeHouse
Solar Enthusiast
One of your cells has to be the worst cell. If the 101.8 Ah cycle capacity lines up with a full charge-full discharge, then that’s not so bad; your weakest cell has a capacity of about 102 Ah. That’s 97% of the advertised capacity.
Since initial balance, did you set the balance start voltage at 3.4 or higher? If you balance below this, it can cause some problems but this seems to be a bit much.
sunshine_eggo
Happy Breffast!
cells sitting at 3.1XX don't have much left in them. Did you actually get your 101.8Ah capacity? If so, I'd call it a win and try to not deplete the battery.
From 101.8 you'd need to substract about 28 Ah. That was before I started the discharge test.
@Skypower yes, balance is set at 3.41
@sunshine_eggo minus about 28 Ah, that would be 74 Ah, pretty much inline with what I've heard about these cells. Unfortunately it was too late when I found out. I could cope with the reduced capacity in amp-hours but the highest of the lowest disconnect voltage I can set on the AiO inverter is 24V and as seen in the screen capture when that cell is depleted the battery voltage is way above 24V.
That being said I'm going to order grade A cells that come with warranty, from a European store. Lesson learned.
Quattrohead
Solar Wizard
Cell 7 is the weakest for sure, but one of them has to be.
I am testing a commercial rack battery and now I have BMS monitoring setup I can see a weak cell that runs high at the top of the charging cycle and is first to bottom out. But the battery does just about make it's rated capacity.
I say just use it.
I am testing a commercial rack battery and now I have BMS monitoring setup I can see a weak cell that runs high at the top of the charging cycle and is first to bottom out. But the battery does just about make it's rated capacity.
I say just use it.
If I don't discharge it to less than 3.2V per cell it's good, but I risk running into the undervoltage alarm and the BMS cutting out the power. I'm currently under tests so it's nothing but a rather annoying situation but once this powers the critical stuff it's going to cause chaos if the power is out.
Lt.Dan
Solar Wizard
You could look into just purchasing 2x replacements for the low cells. I have done this a number of times.
sunshine_eggo
Happy Breffast!
The cells in the vicinity of high 3.1V are only 15-20% remaining... that means even the good cells likely have no more than 90Ah in them.
It's summer now and the gas boiler doesn't fire the circulation pump, I only have a dummy load (fan and lights) simulating the 55 W load my router/microserver/switch is drawing usually. That should account for about 1.4 kWh daily. Add the inverter's own consumption, about the same and we get to 2.8 kWh, which is obviously much larger than the battery pack capacity. As the loads draw power mainly from the solar panels during the day I have the full available capacity over night.
But this is going to change in winter, and add to the fact that the orientation is less than ideal, with one panel shaded late in the afternoon, I'll end up with a dead battery if not during the night then during the day. I have an additional controller with 880Wp ready for the other side of the roof which doesn't get shaded but again orientation is crap. However this is going to compensate a bit but not as much as I need, hence I'll need to resort to charging from grid. This adds extra work because the shed is wired for a maximum of 3.5 kW (I think that's an AWG 14 cable, 2.5 sq mm in Europe, and a 16A breaker) whereas the AiO needs to pull 4.6 kW (and that is an AWG12 cable if I'm not mistaking, 4 sq mm in Europe and a 25A breaker).
My best bet is having a battery I can trust, not the Liitokala PoS.
But this is going to change in winter, and add to the fact that the orientation is less than ideal, with one panel shaded late in the afternoon, I'll end up with a dead battery if not during the night then during the day. I have an additional controller with 880Wp ready for the other side of the roof which doesn't get shaded but again orientation is crap. However this is going to compensate a bit but not as much as I need, hence I'll need to resort to charging from grid. This adds extra work because the shed is wired for a maximum of 3.5 kW (I think that's an AWG 14 cable, 2.5 sq mm in Europe, and a 16A breaker) whereas the AiO needs to pull 4.6 kW (and that is an AWG12 cable if I'm not mistaking, 4 sq mm in Europe and a 25A breaker).
My best bet is having a battery I can trust, not the Liitokala PoS.
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I could theoretically do that but now I lack trust in that vendor.
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Lt.Dan
Solar Wizard
Surely there are other vendors that sell that same cell. Don't buy from them again.
I purchased another 8 105ah cells from Liitokala. This time I have a EBC-A40L tester. 2 of the batteries I've tested (using various settings) come out to 88ah. I've got my original battery disassembled and will test one of those cells next. They've been in use about 4 months.
This is the store link: https://www.aliexpress.com/store/1100552573
I won't be ordering additional cells from them again
This is the store link: https://www.aliexpress.com/store/1100552573
I won't be ordering additional cells from them again
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Alkaline
Solar Wizard
88 AH, all things considered you did OK considering you dealt with LittoKala, I was expecting in the mid 70's.
meetyg
Solar Enthusiast
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- Jun 4, 2021
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I think that these are not EVE 105Ah cells, but rather the LF90K.I purchased another 8 105ah cells from Liitokala. This time I have a EBC-A40L tester. 2 of the batteries I've tested (using various settings) come out to 88ah. I've got my original battery disassembled and will test one of those cells next. They've been in use about 4 months.
This is the store link: https://www.aliexpress.com/store/1100552573
I won't be ordering additional cells from them again
I also have ordered supposedly 105Ah cells on Aliexpress, but they all came around 85-88Ah like yours.
The weight difference between the 105Ah and the 90Ah is so subtle, that you almost can't tell the difference.
Seems like alot of the 90Ah cells are being sold across multiple sellers on Aliexpress.
Maybe they are old EVE batches or surplus (used?) from an EV project.
The weight of the cell that tested at 88.95ah is 2034 grams.
I finished testing the first cell in my original order and it tested at 76.1ah. Not sure of it's capacity when I first received it. This cell's been lightly used for 4 months in a 24v battery. This cell weighs 2035 grams.
I'll continue testing all the cells and hopefully they're all close in AH. I may end up with a 76ah 24v and a 88ah 24v battery. :/
The link is pointing to a store that is "over capacity", no other info. I guess they took it down.I purchased another 8 105ah cells from Liitokala. This time I have a EBC-A40L tester. 2 of the batteries I've tested (using various settings) come out to 88ah. I've got my original battery disassembled and will test one of those cells next. They've been in use about 4 months.
This is the store link: https://www.aliexpress.com/store/1100552573
I won't be ordering additional cells from them again
Regarding the 80-90-ish cell capacity, it's consistent to what I get from the JK BMS coulometer when doing discharge tests using a 12000 BTU mini split.
I won't be ordering cells from Aliexpress ever. I have been saving for an Elerix 48V/100Ah kit which I'll break down into 2 24V/100Ah banks connected in parallel. After doing that I'll break the 24V/80-ish Ah Liitokala bank into 2 12V "good" and "lousy/experimental" banks.
Oh I guess I've missed your post. Just googled "lf90k eve", came across the very same cell dimensions advertised by Liitokala and finally the picture is complete. The "105 Ah Liitokala cells" are Eve LF90K with lasered out QR codes and new QR codes etched on them, that resolve to a Chinese site, with nothing that can identify the cell. They buy all crap they can find, laser out the original codes and sell the 90 Ah cells as 105 Ah cells. They don't even bother to test them because their "warranty" consists in "send cells back to the factory in China". Has anyone tried to send a LiFePO4 cell not overseas, but in a neighboring country, in Europe? Yeah, thought so... The shipment fee rivals, equals or exceeds the value of the cell, if you write "lithium battery" on the AWB.
