I remember in the old days you'd have to start a car's engine or drive it around a bit if it was sitting for long periods of time, say, when you were on a trip and left it at home. Is this true with the Prius? Will the battery stop working if I'm letting it sit on the driveway for weeks without using it?
The 12v battery WILL eventually be drained. Same for any car. But the Prius 12v is not a large capacity battery, it doesn't need to be because it doesn't turn the engine over for it to start. The hybrid battery can go several months before it too will eventually drain. If you must leave it, perhaps a 12v solar charge could be installed to keep it charged up.
Our usage is “sporadic”, the car idle between usage, sometimes just a few days, occasionally up to two weeks. It’s garaged and the 12 volt battery on a smart charger. When we do use it’s usually a good drive, say at least 10 kms, sometimes 50~100, getting the engine fully warmed. the current 12 volt battery was installed in September of 2015, and still tests well above specd CCA. the hybrid battery seems to behave as always. Owners manual mentions hybrid battery and downtimes, says (paraphrasing) as long as it’s not months of downtime it can handle it.
I parked my Prius and Prius-C in garage for 1.5 and 2 years respectively. I checked the traction battery SOC levels every 3 to 6 months. The SOC barely moved, staying at 5 - 6 bars.
