I build 3 DYI jehugarcia (youtube) 18650 battery packs, each pack consist of 9 times 7x18650 cells with a 24v output. So, in total 63 cells. Each 18650 has an average 2400mAh.
So, in a grand total I have 3 packs of 63c = 189 cells.
Each pack has it’s own BMS and they are charged by a Victron 100/30 MPPT Solar charge controller. A BMV 702 keeps an eye on things and a Raspberry PI with VictronOS on it to log statistics to a VRM dashboard.
All well so far and after weeks of charging and discharging the cells are still very much balanced. A Victron Battery Protect as a measure to prevent to low a discharge and opens at float voltage to keep the MPPT as maximum power. Basically, this pack functions as an equalizer as the total capacity isn’t enough for off-grid purposes. (In The Netherlands we have clouds now and then with the sun disappearing).
The issue I have is to calculate the correct total Ah settings in the BMV shunt. I think each pack of 9 has a 21Ah capacity, so a total 63Ah. But the key question is, did I calculate it correctly?
Hope one of you can assist.