http://demonpowerproducts.co.uk/prod...e-graph-p-5812
As this states a programmable cutoff I assume it'll do what you want, but you might need to contact Nick or google
Thing is that you'd be better charging on a limited capacity charge as lipos are designed to be charged CC/CV, contast current (to 4.2V per cell) then constant voltage. The charger lowers the charge current when it reaches 4.2V per cell and keeps lowering it whilst maintaining the voltage. So everytime the cell goes to 4.21 the charge current drops by say 0.1A, but if you're not at 4.2V the voltage isn't going to be stable (espcially as low as 4.15) as the cell will always try to reach its terminal voltage. (I know this won't apply for older cells that no longer achieve that but the chargers get them as high as they will go as the cell will remain at its max voltage)