With our Solar panels we charge the Redback battery up when the sun shines and so trim our hedges for free. To do the hedge tops, just set the cutter to the angle you want, adjust its height. Position it, switch on and walk along the hedge. Job done. Even the neighbour likes it.
The battery acts as a counterweight to the blade making it easier to manipulate. It's not very noisy but very powerful. I have cut through 20mm stalk thicknesses, and there is no degrading in power, right up to when the battery runs out, when it just stops. A good choice if you don't like ladders.