Okay for car to sit?

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.

 

a 13 year old hybrid battery is in danger of going bad if it sits too long. you can't predict it.

 

be careful of vermin as well. they move in when you move out, and can devastate the wiring et al

 

See Post #1...

 

Didn't hurt my car yet to be driven only every 4/5 weeks for like 30 miles /
Just put some battery tender/minder on your 12v battery /

 

The 22v battery is keeping power to the computers, to keep the settings, among other things.
If it dies, you lose all the setting. And the car won't start, or go to the READY mode.
A weak 12v battery will trigger all kinds of codes and warnings. Computers don't like lower voltage
than they need.

So you NEED to keep it charged up. It's never good for ANY car to sit idle for long periods of time.
The 12v battery gets weak and eventually dies. Seals lose lubrication and harden, rust starts.
Rats/squirrels and bugs make nests and eat wires.

Keeping a battery maintainer on it will save you a lot of issues. "IF" you have someone that can drive
it for you at least once a week, for 30 minutes or so, it will be good for the car.

 

if it were mine, i would ask someone to drive it for 15 or 20 minutes every couple weeks, and disconnect the 12v negative, or put a maintainer on it

 

it just clips onto the charge point in the fuse box under the hood, and you plug it in

 

30 bucks genius1