I am on a hourly meter electric so my charge for electric changes every hour. I was wondering how many kilowatts are needed to recharge a 2012 Volt battery that is run down? Reason I am asking is that when recharging at night I see sometimes my electric is as low as -.01 cents per KWh and might go up to +.02 cents per KWh at the highest. It usually takes around 3 hours on my Clipper creek 220 unit. I have seen it at a record low of -16 cents per KWh. I am in suburb of Chicago on ComEd electric.