10 days is not too long a period to leave the Volt plugged in or fully charged and unplugged. If you were going to be away for longer than 4 weeks/1 month then there are specific recommendations in the Volt Owner's Manual. These include storing the Volt with a 30% SOC and not leaving the Volt plugged in over a prolonged period. The other consideration is to connect a 12V battery tender to the Volt's 12V AGM battery so that it does not run down, leave you unable to start the Volt when you return. I would be concerned about leaving the Volt plugged in in case there was an electrical storm. If there is someone at home who could unplug the Volt in case of thunderstorms then I would have no issue with leaving the Volt plugged in for 10 days.