I once ran my 2017 Premier down to 1 bar on a road trip and wanted to use electric in town that night. I switched to MM and let it charge up to 2 bars then switched back to Hold until I entered town and switched back to Normal. I never had to shut the car down after MM. I suspect in your scenario you would not need to turn then car off. You could just shift to Normal and away you could go.No bars and 0 ev miles is not bad for the battery, it usually just means the dealer hasn’t taken the time to recharge the battery. To test out battery-powered driving in a Gen 2 Volt if the dealer hasn't taken the time to recharge the battery, just start the car and switch into Mountain Mode, even while parked, and in ~10 minutes the system will charge the battery to the ~2 bar level. You may need to then turn the car off and restart it to get use of that battery power. You can use it to drive Electric Miles, but the kWh Used won’t increase when you do (it’s not grid power).