I would let it drop to under one amp, as long as after an hour their resting voltage is above 3.5v you can be certain they were fully saturated.How close should the current drop when top balancing? I have 4x 90Ah cells as a patient. On the first try, I charged the cells in parallel at 3.60v (8A charge) and stopped charging when the current had dropped to 0.020A then I waited 1.5 hours, switched to series and did a capacity test with the BMS. The capacity test ended already at 12V even though the lowest voltage was set to 10V.
I suspect the reason was "cell different volt protect" this parameter my daly bms won't let change, it's always 0.26V. Bms did not report any error code. After 1.5h of rest, the diff volt was 0.063V, at the beginning of the test 0.008V and at the end of the test 0.274V (lowest cell 2.868V).
Now I recharging the cells in parallel, the current has dropped to 0.016A and doesn't seem to be dropping from it. Will I stop charging already, or will I still let it charge?
How many differences in current should there be when the cells have rested?
Do I let the cells rest in parallel, or series? I am going to do the next capacity test with JBD BMS. I use the DL24P capasity tester.
Probably one of your cells is significantly less capacity than the others and is triggering low voltage disconnect.
Did any cell reach 2.5v (with a cell at 2.8v, I suspect it did under load and you just missed it)? If this is the case, it won't matter which BMS you use, as long as it works.
You can let cells rest in either parallel or in series, manufacturers usually specify a one hour rest after a full charge for capacity testing purposes.
I would have just charged them back up while still in series, it's much faster that way. Just be sure to use a BMS.
Two resources you should check out:
![diysolarforum.com](https://www.mobile-solarpower.com/uploads/1/2/9/6/12964626/img-20190331-124124-456_1_orig.jpg)
Top Balancing LiFePo4 Cells using a low cost benchtop power supply.
To get the paper, click on the orange at the top of this page. This is a tutorial with detailed steps on how I top-balance my LiFePO4 Cells using a low-cost benchtop power supply. To get the tutorial, click on the orange "Download" button...
![diysolarforum.com](https://www.mobile-solarpower.com/uploads/1/2/9/6/12964626/final-favicon_orig.png)
![diysolarforum.com](https://www.mobile-solarpower.com/uploads/1/2/9/6/12964626/img-20190331-124124-456_1_orig.jpg)
Explanation for Beginners of Top and Bottom Balance
This is a beginners explanation of top and bottom balancing cells that should help you understand what it is all about. To get the document, click on the orange button at the top of the page. NOTE: This is not intended to be a tutorial of how...
![diysolarforum.com](https://www.mobile-solarpower.com/uploads/1/2/9/6/12964626/final-favicon_orig.png)
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