Benet,
I saw your posting for the first time last night. I am in the camp that say that present battery technology is what limits your idea from being applied.
I did have a look on the net to see what the performance figures for rechargeable batteries were. Some recent research anticipates an energy density of about 1000Kj/Kg (a very rough guide).
Suppose an R22 needs 90 hp (or 67 Kw) of power to cruise and supposing these batteries weigh what a full load of fuel would weigh in an R22: 81 Kg. Then you have on board 81000 Kj of energy which your motor would use at a rate of 67 Kj per second. You have power to cruise for 81000/67=1209 seconds or just over 20 minutes.
A seven or eightfold increase in battery energy density is needed before the idea becomes practical, I would guess.