JK BMS Monitor measures the real balance current and the time spent balancing every day, and draws the cell gap at the top of each charge. See it in the demo →
The formula
days = capacity × gap ÷ 2 ÷ (balancer current × 0.6) ÷ hours a day above the start voltage
Half the gap is enough: the charge taken from the fullest cell is given to the emptiest one, so they meet in the middle. The 0.6 factor accounts for the balancer working below its maximum current as the gap closes.
Why the balancer works so few hours
A JK board balances only when a cell is above the start voltage (often 3.40 V) and the gap is above the trigger. On a LiFePO4 pack that happens near the top of charge, typically an hour or two a day when the inverter lets the pack reach full charge. If your inverter stops charging earlier, the balancer may never run at all.
When a manual top balance is better
If the result runs into weeks, the gap is too large for the balancer alone. Bring all cells to the same full voltage in parallel with a bench power supply before assembly, or charge the low cell on its own, then let the active balancer keep them together.
Keep reading
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