I am smart plug dumb, but I learned from the owners manual that it is recommended to keep the Volt charging when able. I turned to the owners manual after I heard lots of noises like it ate my mama's cooking. She is sweet but a crappy chef. This was going on after being fully charged and even after it has been sitting for days. The manual also suggests to keep the Volt plugged in with temps below 32F or above 90F to maximize the battery life. A nice feature that has prevented degradation in all Volts as compared to other EVs. We have been below 32F for a few days now here in NC. And with 8" of snow I have left the Volt stay put. It is gurgling more than before. So I would keep it powered fully.