I forgot to add re the explanation about energy required to accelerate is the same (fast or slow): I agree. I think the concern about rapid acceleration was mostly due to PbA batteries where you have to worry about Peukert and not over-stressing them too much. There would be some marginal I2R losses but I would think very hard to measure. The other impact is that your average speed over a certain distance would increase slightly but unless you're constantly speeding up and slowing down it'd be hard to measure.
Relieve some more guilt: add PV to your roof and drive on solar!
