Fangpusun battery balancer, a device used in solar charge controller systems to equalize the state of charge between two series-connected 12V batteries in a 24V system.
It helps extend the life of the entire battery bank by ensuring all batteries converge to the same state of charge.
The device operates by drawing a current of up to 0.7A from the battery (or parallel-connected batteries) with the highest voltage to balance the charge.