Hi all,
So, I'm currently testing my 8 280Ah cells.
I charged the individual cells to a certain point, which in hindsight shouldn't have done cause it takes way too long with a 10A power supply. So when I got the charger, I did a quick charge and then proceeded to top balance as per instructional PDF from this forum, with a maximum voltage of 3.65V. I stopped the top balance when the current flowing was below 0.9A.
Then I started the (slow) capacity test, with a load of about 175W.
This went well for a long time, for somewhere around the 5000Wh mark, the cell voltage started to drift apart.
At about 6000Wh/233Ah and a voltage difference of 0.46V and a sum voltage of 23.2V (according to the Daly Bluetooth App) I decided to stop the test (for now) after running for 35 hours (with a pause during the night/when I was away).
Between 5000Wh and 6000Wh, the voltage dropped quite fast.
The Daly App in which I entered 280Ah as the rated capacity now shows 13% SOC, 87% would mean about 243Ah gone.
Did I stop the top balance too early, before hitting top capacity? What is an acceptable voltage difference between cells? Notably, "Cell 1" holds 3.179V, while the lowest cell has 2.728V.
Any pointers?
Thanks,
Martijn
So, I'm currently testing my 8 280Ah cells.
I charged the individual cells to a certain point, which in hindsight shouldn't have done cause it takes way too long with a 10A power supply. So when I got the charger, I did a quick charge and then proceeded to top balance as per instructional PDF from this forum, with a maximum voltage of 3.65V. I stopped the top balance when the current flowing was below 0.9A.
Then I started the (slow) capacity test, with a load of about 175W.
This went well for a long time, for somewhere around the 5000Wh mark, the cell voltage started to drift apart.
At about 6000Wh/233Ah and a voltage difference of 0.46V and a sum voltage of 23.2V (according to the Daly Bluetooth App) I decided to stop the test (for now) after running for 35 hours (with a pause during the night/when I was away).
Between 5000Wh and 6000Wh, the voltage dropped quite fast.
The Daly App in which I entered 280Ah as the rated capacity now shows 13% SOC, 87% would mean about 243Ah gone.
Did I stop the top balance too early, before hitting top capacity? What is an acceptable voltage difference between cells? Notably, "Cell 1" holds 3.179V, while the lowest cell has 2.728V.
Any pointers?
Thanks,
Martijn