Personal use of government facilities and services should not be allowed. If allowed, just where do you draw the line?
Well, as an example, current DoD information system policy allows for "reasonable" personal use, basically things like personal e-mails, limited internet use, and so forth as long as it is appropriate, of a limited basis, and doesn't interfere with normal work duties. Also, on deployment, especially on a Navy ship underway, people don't have a choice but to use the government's information system to e-mail family back home and such.
As far as charging an electric vehicle on base, I thought I remembered hearing there was some federal facilities regulation that didn't allow it, but I think it's something that could be changed if enough people try to push for it. Also, I imagine it was probably something put into motion before cars like the Volt and Leaf were really looking like they would be coming to market. In this case, just the amount of power that it would take to charge an electric car might be the basis of the issue. For example, using a power outlet in command spaces to charge your cell phone would probably not raise any concern by anyone (especially if that's the recall number people have for you), or other small electronic devices like that, as the electricity used is barely a blip compared to things like air conditioning the building or running machinery, etc. The electricity to charge a Volt or Leaf would be relatively significantly greater (even if it's only around $1.50 a day), so various people might see it more like buying gas for an ICE vehicle. In which case, maybe since you can buy gas at the exchange on base there's a way to see if the NEX/AAFES/MCX/CGX would support installing some sort of pay to charge plugs in coordination with base facility commands, though they would have to be in pretty much every parking lot to ensure they are placed where people can use them effectively.