Nubo said:
DIY builders have been achieving essentially the same result for years in terms of the cells running out at the same time. It’s called “bottom-balancing”. Doesn’t require a truckload of relays. In fact no BMS at all.
No, this is not bottom balancing.
When top balanced, all cells are fully charged when the pack is charged, and get more out of balance as the battery is discharged.
When bottom balanced, all cells are fully discharged when the pack is discharged, and get more out of balance as the battery is charged.
In both top and bottom balanced, the current is the same in all cells. So the weakest cell will go from maximum to minimum voltage, and all other cells will have a lower voltage swing.