[himalaya]

NiMH packs are self-balancing.

Being insensitive to overcharge, all NiMH cells in a pack can get fully charged just by slightly overcharge EVERY cell. i m sure you noticed all NiMH get warm at the last charging period, that's a sign the cell is full and is converting charging electric energy to heat instead of chemical energy form. This will ensure all cells are full/balanced.

Lipo doesn't have the capability to convert excessive electric charge into heat, they are strictly forbidden from getting overcharged. so a balancer is needed.

Being different from Lipo, NiMHs are not voltage terminated to detect the charge end point. All lipo from all manufacturer have a voltage threshold of 4.20V, but not Nixx batteries, their fully-charged voltage vary from cell to cell, and changes even kept untouched. so most chargers don't terminate Nixx charge by voltage, they do that by delta-V and/or temperaure. Parallel charge Nixx batteries can be practical but not acurate.