What is the battery "balance cycle"?

[Phillip Low]

The instructions say this, "The pack will relax, then do a balance cycle, then top off" So is the balance cycle something I do or is it something the battery pack does while "relaxing"??? Everywhere I look is says this must be done to balance the battery, but never saying how or who or what!!!

 

[DaveB]

The battery will allow "fast" charge to about 80%, then gives a cool down period (relaxing) it then checks each cell and charges any that are low, when all three are the same it tops off to 100%. It's like a fancy lipo charger in each Battery