Balance

cell balance: Describes the balance of of voltage between the cells of a battery. Older lead-acid batteries are used without active balnce, they are "stable". Lithium batteries are used with BMS, since the cells use to "drift", which means their discharge characteristics are not equal or their capacity does not mach. That's why their voltages have to be matched - at least after a few cycles. "Bleeding"- balancer circuits discharge the cells with the higher voltages till they match the lower ones. They are common in RC-type chargers and other commercial BMS