Cell balancing is the act of making sure all cells in a battery are at the same voltage. When building a lithium-ion battery, the process involves connecting many cells together to form a singular power source. In ideal circumstances, brand-new cells will all be at the same voltage level. This,. There are several ways this can be achieved. Batteries can be top-balanced or bottom-balanced. They can be actively balanced or passively balanced. The quickest way to balance cells is by burning off the excess energy. For example, if all of your cell groups but. Top balance is when the cell groups in a battery are balanced during the charging process. There are many applications that are well suited for top balancing, but the best example of such. To manually bottom balance a battery pack, you will need access to each individual cell group. Let's imagine that we have a 3S battery and the cell voltages are 3.93V, 3.98V, and 4.1V. Connect one end of a load resistor to the junction between cell group 2 and cell. Bottom balancing, as you would expect, is pretty much the opposite of top balancing. Bottom balancing is used when getting the absolute most out of each discharge cycle is the most important.