Grade A cells, first charge a cell drifts 0,08V. Would you accept this ???

[HKZBob]

Dear Forum,

I have purchased 4 Lifepo4 cells 200Ah Grade A from N.... Official Store.
When I opend the box the voltage level was
Cell1: 3,271V
Cell2: 3,274V
Cell3: 3,271V
Cell4: 3,273V


Then I paraelled them and charged the up to 3,65V and rested them. Current dropped to Zero
I did Top Balanceing as Will proposed. All cells had exact the same voltage!!!

Then I have build my 12V pack and I have tested the capacity: "Over 200AH"

Now I have charged them on purpose without BMS and surprise the cell voltage looks like this.
Cell1: 3,49V
Cell2: 3,49V
Cell3: 3,41V
Cell4: 3,49V

Cell no. 3 is already off by 0,08V buy one charge. I remember Will saying in his video new Grade A cells which are okay never drift.
Now after one charge it is already off close to 0,1V.

Is this variation allowed from quality prospective for Grade A cells.

This looks to me not in specification since all other 3 cells working well.


What do you think?? Here a link of the measurement.

Lifepo4 cell drifting.mp4

drive.google.com

Bob

 

[Mtour]

You could try arranging them In a different order and see if the imbalance follows the cell...

 

[HKZBob]

Yes it will follow, I did already.

So is the cell a grade A cell

 

[snoobler]

First, you're assuming ANY of them are ACTUALLY "grade A". They'll tell you anything to get you to buy them.

Second, a top balance means the voltages are ONLY equal at the balance voltage. They may deviate at all states of charges below that.

Third, your partial charge allows for no meaningful conclusions. Cell 3 only shows a difference, which isn't necessarily positive or negative.

Lastly, repeat charge to 14.4V and assess cell balance as this is the only place they should be balanced.

 

[ghostwriter66]

0.08 seems perfectly fine for me ... theres lots of reasons for this but none of them concerning unless you plan on charging it up and then storing for extended periods of time ... just my .02 ... I would not be worried ...

 

[OnTheRoadAgain]

A bit older thread but.....

if you are referring to NINTHCIT Official Store.........

 

[Supervstech]

A bit older thread but.....

if you are referring to NINTHCIT Official Store.........

I also received some "Grade A brand new" cells.

But they won't charge past 3.377v per cell or 13.5v for the pack.

This wreaks of very used cells masquerading as "New"

Please explain how you charged the cells, and how you are measuring the voltages.

 

[Gazoo]

Please explain how you charged the cells, and how you are measuring the voltages.

It's all in this thread.

 

[Gazoo]

Please explain how you charged the cells, and how you are measuring the voltages.

NM...it's been solved. I have asked him to update his thread so others are aware of what the problem was.