I think I agree with you on the differences being unreasonable. It seems when most people show their results on this forum, they're touting differences down in the thousandths of a volt. However...
I followed the instructions from
Nordkyn design especially the excerpt:
- Don’t waste time leaving cells sitting around connected in parallel. They don’t balance or equalise unless they are being charged in parallel at the end. I have specifically tested that. There is not enough voltage difference to keep driving current between cells until they balance out.
He (Nordkyn) seems to feel very strongly about not leaving cells in the upper knee. Its why I did the 3.9 amp-hour drain immediately after hitting 14.6 volts. I certainly do not know what is the right answer, but after spending hours on Nordkyn's website and seeing how thorough, technical and for how many years he has been doing this, I'll tend to take his suggestions as gospel. According to Nordkyn, your letting it "settle" at the top balance point is very detrimental to the cells. And... the difference in voltages won't drive any appreciable balancing between cells. Will also says that in several videos.
I was not diligent about this other excerpt:
- Bring all the cells up to 3.60-3.65V, disconnect and keep recharging this way until they all hold above 3.50V for at least 30 minutes. They are then full and balanced. Don’t leave the circuit closed and unattended under any circumstances; it would very quickly destroy all the cells.
I will re-do this part and make sure they stay above the 3.5V for 30 minutes.