how much to chare the volt

Figure what your cost/kW from your power company and assume ~12kW for a gen 1 (2011-2015) or ~16kW for a gen 2 (2016+). Of course that is with a fully depleted battery. Here in SoCal I figure it cost me about $1.50 US to charge fully from empty on my '13. I pay about $.12/kW as long as I don't get into the more expensive higher tiers.