Experimental 1 2 3 4 or 5 cells should provide for most of my needs. Just a little more complicated to charge and wire up, but if a cell is below par, I do not have to dump the whole 2S-5S battery. Usually only one cell fails. All cells checked at 3,7 to 4,0 volts so pleased with this purchase so far. Shipping cost extra, but previously not possible to ship to LiPos UK as an item.