Help Required - AliExpress Lifepo4 battery dispute

Kman68

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Sep 25, 2020
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Hi

I think I need your help.

As discussed in this thread: https://diysolarforum.com/threads/looking-for-272ah-or-280ah-cells.20185/

I purchased a 300ah 12v Lifepo4 battery bank from China via AliExpress: https://www.aliexpress.com/item/1005002752049532.html?

The battery finally turned up after 3 months, and I performed a capacity test, and it came out at about 81ah compared to the advertised 300ah. Quite a difference.

However, as I'm sure some of you will have anticipated the seller is not accepting this, and AliExpress have not accepted my evidence that the battery is not as advertised.

I posted this photo of the discharge test, just before it ended, and initially the seller argued that the battery can go down to 10v, so my test wasn't correct,

The minimum voltage of lithium iron phosphate is 2.5X4=10V, and the full-load voltage is 3.65X4=14.6V. The measurement is wrong. The measured voltage provided by the buyer is 10.98V, which is obviously wrong To measure the capacity of the battery, the calculation must be started at the lowest voltage of 10V, and the saturation voltage is measured to 14.6V. .

and now AliExpress are saying that the meter I used (which they sell) isn't valid to do such a test. I think I'm screwed here. Any thoughts?

aliexpress.PNG



My photo below.

81ah.jpg
 

Short_Shot

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Did you fully charge and top balance your cells before starting the test?

10.98 is in fact not a full discharge either.
 

DJSmiley

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11V or 10V doesn't give you another 220Ah....

Proper topbalancing is important, but also for this... I highly doubt that will make a huge difference. It does help, but it depends how much the individual cells are apart from eachother.

What was the individual cell voltage when reaching the LVD?

As for Ali buyer protection: Its not that great, more of a little luck... You probably have to contact your CC company to file a claim. But due to the long shipping periods I doubt if they will honour your request... (If it's something like 30 or 60 days you're way over it...)

I hope you find a way to get this fixed, but I won't take a bet on it.....
 

Kman68

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I've realised this thread is technically in the wrong sub-forum, as this is not a DIY pack, but a ready built unit - see below:

(please if needed, can a Mod / Admin move it to the right place). Thanks.

IMG_20210915_131415.jpg


As you can see it was 'charged' on arrival. I topped it up using a lifepo4 charger until the amperage dropped to zero (after I took this photo).


IMG_20210915_172749.jpg

With regard to the discharge depth, it did carry on for a little bit past 10.97v but the inverter cut off at about 10.4v with a total discharge of 81.0ah
 

Short_Shot

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I don't know how they figure 100% but it's clear it was not.

What are the dimensions of the whole battery?
 

ericgrand

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13.6V is definitely not a sign the battery is fully charged and balanced. Full charge is 14.6, i.e all cells at 3.65V. Having 0 Amps at 13.6 may be with a low cell, that will trigger the low voltage protection of the BMS.
 

Kman68

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I think the dimensions / weight of the whole unit might be a way to dispute their 300ah capacity claim... the box (33x21x17cm and 13.4kg seems quite small)
 

ericgrand

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It may be that the cells are 75Ah...The Chinese seller are good in cumultaing both voltage and capacity in the description... DO you have a mean to open the battery? It would be good to check the cell inside. Definitely, a 300Ah cell is around 5.5 kg, so the spec are very light... Also comments on the product page are all negative...
 

Kman68

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It may be that the cells are 75Ah...The Chinese seller are good in cumultaing both voltage and capacity in the description... DO you have a mean to open the battery? It would be good to check the cell inside. Definitely, a 300Ah cell is around 5.5 kg, so the spec are very light... Also comments on the product page are all negative...
The unit seems very well sealed, but it sounds like there's little 'warranty' to invalidate.
 

Kman68

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The unit does come with a supplied charger, but it's got a Euro plug.

What I'm going to do is, I have ordered a Euro to UK plug converter, which is arriving tomorrow. I will then attempt to fully charge to battery with their provided charger - they can't object to that surely. I need to read the 'evidence guide' to see what exactly I need to present, in video form it seems.

After that, I'm not sure how I do a full discharge test without buying (probably expensive) kit to do it 'properly'.
 

DJSmiley

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Well.... that case can't fit a 300Ah battery. Also the weight proves this. If you're lucky it's 100Ah at max.

300Ah at <15kg.. well, you've just invented a new generation of LiFePO4 if that were true

For the seal: I have seen some people putting the battery in the freezer. That would harden the glue so you can rather easily take it apart without too much damage as eg shown in the basen review from @LithiumSolar

 

Kman68

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Well.... that case can't fit a 300Ah battery. Also the weight proves this. If you're lucky it's 100Ah at max.

For the seal: I have seen some people putting the battery in the freezer. That would harden the glue so you can rather easily take it apart without too much damage as eg shown in the basen review from @LithiumSolar

Is there a reference I can use? If I can prove that 13.4kg is IMPOSSIBLE to be 300ah lifepo4 chemistry, I don't need to do a discharge test.
 

Short_Shot

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It's 33 x 21 x 17cms and weighs 13.4kg
That is definitely not a 300ah pack.

You've likely got 4x75ah as the other poster claimed and thereby they "sent you what they advertised".

That or it's a 100ah battery and they just straight up lied.

But I would for sure 100% charge it properly and try the test again.


Either way, welcome to Chinese sellers.
 

DJSmiley

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Is there a reference I can use? If I can prove that 13.4kg is IMPOSSIBLE to be 300ah lifepo4 chemistry, I don't need to do a discharge test.

Get any cell specs.. EVE, CATL, Lishen, REPT... All their 270-280Ah cells are at 5.5kg or so for a single cell... at minimum

4 cells, busbars, terminals, BMS and casing.. You would have at least 22-23kg of weight.

Smaller cilindrical cells are similar, or even heavier I think.. And I think they just throw some prismatic cells in a box. Not expecting any decent stuff from them for this price point. Tape, a BMS, and make a bad looking cell, glue a cover and no-one will see the mess inside.

And I agree, they just rate it as 4 cells, 75Ah each, = 300Ah total.

So yes, in their opinion they are right... Its 12.8V (4 cells in series), but also 300Ah of total capacity. (if you would have paralled them). Just some scumbag maths to make it look nice....

They probably never advertised it as 12.8V / 300Ah...., but as seperate values...
 
Last edited:

Mudd

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I saw a tear down of a similar battery also advertised as 300ah recently on here. I think it tested out to 100ah. Crazy thing was once it opened up the case there were stones inside the case to make it heavier. Hopefully you can get some sort of partial refund.


 

Kman68

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That's the exact same battery - I wonder what I can 'use' from Jim's experience to help get some money back?
 

Mudd

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That's the exact same battery - I wonder what I can 'use' from Jim's experience to help get some money back?
Maybe look through his post history he may describe how he got a refund. Otherwise message him direct.
 
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