48v 280 ah Battery Bank

[Luxpower_Gilbert]

Im dealing with a seller that telling me i did it wrong balancing the cells… i tested all the cells with EBC-A40L my average results is 170ah…
Before i did the test i parallel all the cells for about a week as they arrived and then charged them to 3.6v with 50amp multiples charger and it took forever. Once it reach to 3.6v i let it sit for days to equalize them…
and then i started testing them by one by one, im on the last cell today.. i will post some of the results here once i get home from work…

Test cycle:
set the EBC-A40L to
Step1: CV- 40a charged to 3.65v, cut at 5a
Step 2: wait 10 mins
Step 3: CC- 40a discharged to 2.5v
Step 4: CV- 3.2v 40a

 

[sunshine_eggo]

Individual testing of the cells eliminates any concerns with balance technique provided you didn't take them out of operating limits (charge too high, too fast, etc.).

Your test cycle should yield reasonably accurate results. I would use a clamp DC ammeter to confirm that the unit is reporting accurate amp readings.

I would be happy with anything above 260Ah or so.

Most cells are fully charged at 3.65V when current has tapered to 0.05C or 14A in your case. This is typical of all manufacturers, but it may vary. If you have a specific brand of cells, their datasheet may prescribe a specific cycle test for capacity. I would approximate that as best you can.

 

[DJSmiley]

170Ah or 280Ah is a huge difference.

Did you check QR codes (if available) and size if it actually could be 280Ah?

And did you buy the cells at a well known seller? (than 270+Ah should be common)

Based on this differecne, assuming your test was accurate, I would guess you have bought crap cells from Aliexpress.
(In that case, you probably have to take your loss since you opted for the most unreliable bet, and should be lucky to actually have received cells)

 

[Luxpower_Gilbert]

here some photos highest i got is 3 cells around 212 - 222 ah and average from 160 to 175 ah... the seller told me to parallel all the cells until all the cell is same voltage, and the he told me to put them in series with out charging them while in parallel which is we call it top balancing. in my mind that's not how to top balance but i did it his way just to satisfied him... testing supposed to last around 7-8 hours per cell not over 5 hours..

 

[Luxpower_Gilbert]

Individual testing of the cells eliminates any concerns with balance technique provided you didn't take them out of operating limits (charge too high, too fast, etc.).

Your test cycle should yield reasonably accurate results. I would use a clamp DC ammeter to confirm that the unit is reporting accurate amp readings.

I would be happy with anything above 260Ah or so.

Most cells are fully charged at 3.65V when current has tapered to 0.05C or 14A in your case. This is typical of all manufacturers, but it may vary. If you have a specific brand of cells, their datasheet may prescribe a specific cycle test for capacity. I would approximate that as best you can.

tried to scan the bar code and it direct me to Voricorre web site. each cell has sticker of Voricorre

 

[brum]

This doesn't look right. Post pictures of the cell and give us some info about who the seller was.

I would expect something like that if I get my cells from Aliexpress and there is Liitokala mentioned somewhere on the page. But I have doubts that somebody would do that after reading the feedback for them in the forum.

tried to scan the bar code and it direct me to Voricorre web site. each cell has sticker of Voricorre

VariCore maybe (single "r")? They do not produce cells but rebrand whatever they find and resel it. This is the reason for your issue.

What is the cell dimension? How much do they weigh? Are they swollen?

Note: If you go again on a shopping spree look for EVE/CALB/CATL cells. These are well-known brands. And check the section in the forum with recommended sellers. Otherwise, this is pure gambling.

 

[Luxpower_Gilbert]

170Ah or 280Ah is a huge difference.

Did you check QR codes (if available) and size if it actually could be 280Ah?

And did you buy the cells at a well known seller? (than 270+Ah should be common)

Based on this differecne, assuming your test was accurate, I would guess you have bought crap cells from Aliexpress.
(In that case, you probably have to take your loss since you opted for the most unreliable bet, and should be lucky to actually have received cells)

got them on ebay... i think im dealing with a crappy sellers. i will file for refund after all the test his telling me to do and still low capacity...

 

[brum]

Your tests are proper. Just file for a refund without waiting further.

What is the cell dimension? Based on that we can kind of match them to some of the known proper brand cells and see what the actually expected capacity should be.

 

[Luxpower_Gilbert]

This doesn't look right. Post pictures of the cell and give us some info about who the seller was.

I would expect something like that if I get my cells from Aliexpress and there is Liitokala mentioned somewhere on the page. But I have doubts that somebody would do that after reading the feedback for them in the forum.

the sketchy is that he sent 4 damaged cell first and waited until i got it, i sent him all the pictures to him and he told me that those cell are still in full capacity even do they look like that.. that's stupid as F@@@. and he sent (12 cells )the rest of the battery. i think he was testing usps if they can deliver the battery to me. thats y he sent the damages cells first..

 

[Steve_S]

Looking at the Pic, those cells are Punctured and not serviceable !
Pick the damaged cells up and give them a shake, if you do not hear a good Slushing Sound, they are dry & Dangerous ! If that is indeed the case, your lucky they did not catch and smoke out.

I set 8 Cells in Parallel, then charge to 3.650 starting with 40A Current till they reach 0.05C. Allow them to sit in Parallel without any charge so they settle to their proper voltage, then measure each cells voltage & IR with a Yaorea YR1035+ Battery Tester after which I proceed with a capacity test. NOTE that the "Working Voltage" for LFP is from 3.000-3.400 which is where the spec'd AH's come from. This should NEVER be confused with the Allowable Voltage Range of 2.500-3.650 (safety range that causes no harm) which sadly too many do. IF you are NOT getting the required AH from 3.000-3.400 the cells are out of A-Grade PASS Specs.

FYI: Top Charging to 3.650 is only required to activate the cells after long-term storage to fully activate the cells electrolytes or after having been frozen & thawed. Long Term storage is defined as > than 3 months.

LiFePoQR Battery QR scanner (Android App)

LiFePoQR Battery QR scanner - Apps on Google Play

Scan and decrypt the QR code on LiFePO4 cell/battery

play.google.com

Hope it helps, Good Luck.

 

[brum]

Based on the link you send me the size is the same as the other 280Ah cells - 205*174*72mm.

Look for what options you have for a refund. Cells are definitely not good to go for a storage system. The capacity is low and the ones from the picture are damaged. To be so low on capacity these are most likely old used cells. Escalate for dispute on all possible levels - credit card company, PayPal, eBay.

The seller will likely ask to get these returned. Shipping cells is expensive. They are considered dangerous. Be prepared for that.

And close to 3000USD (from the link I got) - this is a pretty high price even for 16 good 280Ah cells. Mine were close to 2200USD shipped from China with DDP terms (taxes are paid by the seller).

i think he was testing usps if they can deliver the battery to me

More likely testing your reaction to the scam he was doing.

 

[sunshine_eggo]

I'm with @Steve_S.

You got sold junk.

 

[Alkaline]

the sketchy is that he sent 4 damaged cell first and waited until i got it, i sent him all the pictures to him and he told me that those cell are still in full capacity even do they look like that.. that's stupid as F@@@. and he sent (12 cells )the rest of the battery. i think he was testing usps if they can deliver the battery to me. thats y he sent the damages cells first..View attachment 121046

wow you got the worst I have seen yet those are not safe to use