Morning Mate

I'm not down with the flow too much with balance chargers but I do know that they are used for when a cell from a multi cell lipo loses balance and drops voltage compared to the others, like my 4S mod
View attachment 948955 this is a pic from EScribe, see cell 2 is lower than the other 3. A balance charge will bring this cell back up to 4.2v, the same as the rest.
It's also good practice to charge lipo batteries with a balance charger if convenient to keep them on track.
I hope this was some help Mate

I might just think of a bit more later this morning when I wake up properly
@ShamrockPat has some good lipo info stored in his noggin', he might be able to help!