There is a too high voltage difference such as, with the highest cell voltage at

`4.22V`

, the lowest cell voltage is below `3.9V`

. But as the BQ waits for **ALL**cells to be > than`3.9V`

(The minimum cell voltage to balance).Here, cell 6 have been unbalanced of 1250mAh above others.

`ChargeFSM`

algorithm is oscillating between `Charge And Balance`

& `Rebalance`

state very slowly, but is never balancing the cells (as lowest cell is < `3.9V`

).
It’s not dangerous, but the battery is just not charging.**FSM details**

c++`1 "Entered state INIT" 1 "Log: 'Initializing environment...'" 1 "Log: 'Environment initialized !'" 1 "Log: 'Initializing battery IC...'" 1 "Log: 'Battery IC initialized !'" 1 "Log: 'Configuring battery IC...'" 2 "Log: 'Battery IC configured !'" 2 "Log: 'Initializing SoH...'" 2 "Log: 'SoH initialized !'" 2 "Log: 'Waiting for BQ cells readings...'" 2 "Log: 'Initializing SoC...'" 3 "Log: 'SoC initialized !'" 3 "Log: 'State fields initialized!'" 3 "Log: 'Battery initialization complete!'" 3 "Left state INIT" 3 "Entered state IDLE" 3 "Log: 'transitioning from INIT to IDLE'" 10 "Left state IDLE" 10 "Entered state CHARGE" 10 "Log: 'Charge enters charge-and-balance mode'" 10 "Log: 'transitioning from IDLE to CHARGE'" 6271 "Log: 'Battery is fully charged'" 6271 "Log: 'Charge leaves charge-and-balance mode'" 6271 "Log: 'Charge enters rebalance mode'" 6573 "Log: 'Battery not fully charged'" 6573 "Log: 'Charge leaves rebalance mode'" 6573 "Log: 'Charge enters charge-and-balance mode'" 6785 "Log: 'Battery is fully charged'" 6785 "Log: 'Charge leaves charge-and-balance mode'" 6785 "Log: 'Charge enters rebalance mode'" 7087 "Log: 'Battery not fully charged'" 7087 "Log: 'Charge leaves rebalance mode'" 7087 "Log: 'Charge enters charge-and-balance mode'" 7228 "Log: 'Battery is fully charged'" 7228 "Log: 'Charge leaves charge-and-balance mode'" 7228 "Log: 'Charge enters rebalance mode'" 7531 "Log: 'Battery not fully charged'" 7531 "Log: 'Charge leaves rebalance mode'" 7531 "Log: 'Charge enters charge-and-balance mode'" 7638 "Log: 'Battery is fully charged'" 7638 "Log: 'Charge leaves charge-and-balance mode'" 7638 "Log: 'Charge enters rebalance mode'" 7941 "Log: 'Battery not fully charged'" 7941 "Log: 'Charge leaves rebalance mode'" 7941 "Log: 'Charge enters charge-and-balance mode'" 8029 "Log: 'Battery is fully charged'" 8029 "Log: 'Charge leaves charge-and-balance mode'" 8029 "Log: 'Charge enters rebalance mode'" 8331 "Log: 'Battery not fully charged'" 8331 "Log: 'Charge leaves rebalance mode'" 8332 "Log: 'Charge enters charge-and-balance mode'" 8407 "Log: 'Battery is fully charged'" 8407 "Log: 'Charge leaves charge-and-balance mode'" 8407 "Log: 'Charge enters rebalance mode'" 8709 "Log: 'Battery not fully charged'" 8709 "Log: 'Charge leaves rebalance mode'" 8709 "Log: 'Charge enters charge-and-balance mode'" 8775 "Log: 'Battery is fully charged'" 8775 "Log: 'Charge leaves charge-and-balance mode'" 8775 "Log: 'Charge enters rebalance mode'" 9078 "Log: 'Battery not fully charged'" 9078 "Log: 'Charge leaves rebalance mode'" 9078 "Log: 'Charge enters charge-and-balance mode'" 9139 "Log: 'Battery is fully charged'" 9139 "Log: 'Charge leaves charge-and-balance mode'" 9139 "Log: 'Charge enters rebalance mode'" 9441 "Log: 'Battery not fully charged'" 9441 "Log: 'Charge leaves rebalance mode'" 9441 "Log: 'Charge enters charge-and-balance mode'" 9496 "Log: 'Battery is fully charged'" 9496 "Log: 'Charge leaves charge-and-balance mode'" 9496 "Log: 'Charge enters rebalance mode'" 9798 "Log: 'Battery not fully charged'" 9798 "Log: 'Charge leaves rebalance mode'" 9798 "Log: 'Charge enters charge-and-balance mode'" 9849 "Log: 'Battery is fully charged'" 9849 "Log: 'Charge leaves charge-and-balance mode'" 9849 "Log: 'Charge enters rebalance mode'" 10151 "Log: 'Battery not fully charged'" 10151 "Log: 'Charge leaves rebalance mode'" 10151 "Log: 'Charge enters charge-and-balance mode'" 10197 "Log: 'Battery is fully charged'" 10197 "Log: 'Charge leaves charge-and-balance mode'" 10197 "Log: 'Charge enters rebalance mode'" 10500 "Log: 'Battery not fully charged'" 10500 "Log: 'Charge leaves rebalance mode'" 10500 "Log: 'Charge enters charge-and-balance mode'" 10542 "Log: 'Battery is fully charged'" 10542 "Log: 'Charge leaves charge-and-balance mode'" 10542 "Log: 'Charge enters rebalance mode'" 10844 "Log: 'Battery not fully charged'" 10844 "Log: 'Charge leaves rebalance mode'" 10844 "Log: 'Charge enters charge-and-balance mode'" 10882 "Log: 'Battery is fully charged'" 10882 "Log: 'Charge leaves charge-and-balance mode'" 10882 "Log: 'Charge enters rebalance mode'" 11184 "Log: 'Battery not fully charged'" 11184 "Log: 'Charge leaves rebalance mode'" 11184 "Log: 'Charge enters charge-and-balance mode'" 11220 "Log: 'Battery is fully charged'" 11220 "Log: 'Charge leaves charge-and-balance mode'" 11220 "Log: 'Charge enters rebalance mode'" 11522 "Log: 'Battery not fully charged'" 11522 "Log: 'Charge leaves rebalance mode'" 11522 "Log: 'Charge enters charge-and-balance mode'" 11554 "Log: 'Battery is fully charged'" 11554 "Log: 'Charge leaves charge-and-balance mode'" 11554 "Log: 'Charge enters rebalance mode'" 11856 "Log: 'Battery not fully charged'" 11856 "Log: 'Charge leaves rebalance mode'" 11856 "Log: 'Charge enters charge-and-balance mode'" 11885 "Log: 'Battery is fully charged'" 11885 "Log: 'Charge leaves charge-and-balance mode'" 11885 "Log: 'Charge enters rebalance mode'" 12188 "Log: 'Battery not fully charged'" 12188 "Log: 'Charge leaves rebalance mode'" 12188 "Log: 'Charge enters charge-and-balance mode'" 12214 "Log: 'Battery is fully charged'" 12214 "Log: 'Charge leaves charge-and-balance mode'" 12214 "Log: 'Charge enters rebalance mode'" 12516 "Log: 'Battery not fully charged'" 12516 "Log: 'Charge leaves rebalance mode'" 12516 "Log: 'Charge enters charge-and-balance mode'" 12539 "Log: 'Battery is fully charged'" 12539 "Log: 'Charge leaves charge-and-balance mode'" 12539 "Log: 'Charge enters rebalance mode'" 12842 "Log: 'Battery not fully charged'" 12842 "Log: 'Charge leaves rebalance mode'" 12842 "Log: 'Charge enters charge-and-balance mode'" 12863 "Log: 'Battery is fully charged'" 12863 "Log: 'Charge leaves charge-and-balance mode'" 12863 "Log: 'Charge enters rebalance mode'" 13168 "Log: 'Battery not fully charged'" 13168 "Log: 'Charge leaves rebalance mode'" 13168 "Log: 'Charge enters charge-and-balance mode'" 13187 "Log: 'Battery is fully charged'" 13187 "Log: 'Charge leaves charge-and-balance mode'" 13187 "Log: 'Charge enters rebalance mode'" 13578 "Log: 'Battery not fully charged'" 13578 "Log: 'Charge leaves rebalance mode'" 13578 "Log: 'Charge enters charge-and-balance mode'" 13596 "Log: 'Battery is fully charged'" 13596 "Log: 'Charge leaves charge-and-balance mode'" 13596 "Log: 'Charge enters rebalance mode'" 14096 "Log: 'Battery not fully charged'" 14096 "Log: 'Charge leaves rebalance mode'" 14096 "Log: 'Charge enters charge-and-balance mode'" 14114 "Log: 'Battery is fully charged'" 14114 "Log: 'Charge leaves charge-and-balance mode'" 14114 "Log: 'Charge enters rebalance mode'" 14777 "Log: 'Battery not fully charged'" 14777 "Log: 'Charge leaves rebalance mode'" 14777 "Log: 'Charge enters charge-and-balance mode'" 14794 "Log: 'Battery is fully charged'" 14794 "Log: 'Charge leaves charge-and-balance mode'" 14794 "Log: 'Charge enters rebalance mode'" 15822 "Log: 'Battery not fully charged'" 15822 "Log: 'Charge leaves rebalance mode'" 15822 "Log: 'Charge enters charge-and-balance mode'" 15840 "Log: 'Battery is fully charged'" 15840 "Log: 'Charge leaves charge-and-balance mode'" 15840 "Log: 'Charge enters rebalance mode'" 17508 "Log: 'Battery not fully charged'" 17508 "Log: 'Charge leaves rebalance mode'" 17509 "Log: 'Charge enters charge-and-balance mode'" 17525 "Log: 'Battery is fully charged'" 17525 "Log: 'Charge leaves charge-and-balance mode'" 17525 "Log: 'Charge enters rebalance mode'" 20991 "Log: 'Battery not fully charged'" 20991 "Log: 'Charge leaves rebalance mode'" 20991 "Log: 'Charge enters charge-and-balance mode'" 21007 "Log: 'Battery is fully charged'" 21007 "Log: 'Charge leaves charge-and-balance mode'" 21007 "Log: 'Charge enters rebalance mode'" 28281 "Log: 'Battery not fully charged'" 28281 "Log: 'Charge leaves rebalance mode'" 28281 "Log: 'Charge enters charge-and-balance mode'" 28295 "Log: 'Battery is fully charged'" 28295 "Log: 'Charge leaves charge-and-balance mode'" 28295 "Log: 'Charge enters rebalance mode'" 42048 "Log: 'Battery not fully charged'" 42048 "Log: 'Charge leaves rebalance mode'" 42048 "Log: 'Charge enters charge-and-balance mode'" 42061 "Log: 'Battery is fully charged'" 42061 "Log: 'Charge leaves charge-and-balance mode'" 42061 "Log: 'Charge enters rebalance mode'" 58314 "Log: 'Battery not fully charged'" 58314 "Log: 'Charge leaves rebalance mode'" 58314 "Log: 'Charge enters charge-and-balance mode'" 58327 "Log: 'Battery is fully charged'" 58327 "Log: 'Charge leaves charge-and-balance mode'" 58327 "Log: 'Charge enters rebalance mode'" 78447 "Log: 'Battery not fully charged'" 78447 "Log: 'Charge leaves rebalance mode'" 78448 "Log: 'Charge enters charge-and-balance mode'" 78461 "Log: 'Battery is fully charged'" 78461 "Log: 'Charge leaves charge-and-balance mode'" 78461 "Log: 'Charge enters rebalance mode'"`

## Short term solution:

Reduce minimum cell voltage of

`3.9V`

to `3.7V`

-`3.8V`

Add a charge timeout.

## Long term solution

Write ourselves a balancing algorithm. Then instead to have a minimum cell voltage for all cells, we could have this minimum voltage cells per cells.