If you want to go this route:When I'm doing this should I charge it first to 100% SOC and then disconnect it so that there's no load?
The best method would be to keep the cells charging at low current. If you do it without a load, the resting V declines and depending on the load of the light bulb, may give you false readings.
Car bulbs can have 2 filaments, low ~.25A, high ~ 1.0A and both ~1.25A at our 3.4X Voltages.
These BMS should have 43 Ohm resistors for each the balancing circuit. (80mA @3.2V)
You'll want to take the highest cell close to the Lowest cells' projected value ( remember the low cell will gradually rise in V since it's charging). Once you remove the bulb, that cell's V will be a bit higher. Then proceed with next highest cell etc.
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