Prius 2012 Battery Life - when parked

I posted about this problem a while ago. The dealers are told to unplug the battery if stored for more than 30 days. The dealer told me to do this if storing for even 3 days, which I think was a CYA proposition. What we discovered in our case is that our kids probably left the dome lights on, so chalk that one up to user error. That said, we're hesitant now. For example I won't be driving my Prius to a remote trailhead and leaving it parked for a week. In both our cases the weather was cold (for us, in the 30s), which may have played a role even if no user error.

Since then I've gone up to a week leaving the car parked with no difficulties, but it was garaged at 40-60 degrees.

 

If solar charger works, why not use? I use it in my boat.

 

A couple of such "dead" situations and the OEM battery is known to then become unrecoverable requiring a replacement. I would

a. put the 12V on a trickle charger at home overnight BEFORE heading to the airport; this will hopefully bring the 12V battery SOC upto its limit.
b. use the Solar charger while parked at the airport and
c. supplement that with a low-voltage auto-disconnect switch; checkout the mod in my signature.

 

No, that's not normal. It's not uncommon for me to leave my car untouched for that long, and I've never had any problems. I think my parents left theirs untouched for 7 weeks with no problems.

As the car gets older, or if it was subjected to having the 12V battery run down previously, the length of time it can go without being turned on will drop. It may be that your 12V battery is on the way out - though for a 2012, it must have been abused somehow to be dying already.

It's also possible that something was left off, or something ran it down faster than normal; for example, a smart key nearby (even if it's not yours) might be able to drain the battery. Similarly, some sort of radio device might trigger the smart key system.

I would recommend preparing for this type of event (e.g. a jump starter battery pack or jumper cables), and maybe you can find out if it was a random thing or if your car is particularly susceptible to this problem.

 

I did a week in Hawaii and left the car in front of the house. Started right up no problems.

Years ago I left the dome light on in my Honda Civic at the airport my mistake. Came back 3 days later dead as a door nail. Airport staff gave me a jump and away I went.