Parked outside for 8 months. Flying back in soon. Help!?

No. the car needs the hybrid battery to start the engine. The 12V battery is only there to start the electrical system.
It also needs very little power to start, I've started my car with a flat 12V battery and a 2 amp power supply. That's sufficient.

I would check for leaks under the car and if there are none then just try to start it. If it doesn't, use whatever cheap means you have to recharge the 12V battery.

 

Time to replace that battery?

 

is it original?

 

first you need to figure out if you have a healthy 12v. stop by oriellys for a free load test.

once you have a known good one, if the display keeps up, it is probably bad

 

I'm sorry I don't exactly buy this either.
I don't doubt what happened to the poster happened. BUT...
Jumping a battery is a transfer of electrical charge. There is no way the "Battery" knows or cares whether that donor battery is sitting in another Prius, or sitting in a ICE vehicle.

Truth is, you have to be careful with ALL modern vehicles when doing a jump start. I think with a Prius, especially careful. It doesn't take much to possibly cause damage.
Something happened to the Posters Prius. But I don't think it connects directly to it being jumped by a Non-Hybrid 12 volt.

Other owners have jumped their Prius by various methods.
You can buy "portable" batter jump start units.
I don't buy that there is any tangible reason, a Prius needs to only be jumped by another Prius.

 

You're probably right. I think the reason why my Prius went to limp mode after getting jumped by a friend's old crappy 90's pick-up truck was because his battery and truck was old and it probably throws high surges that's why it damaged my hybrid system and dealer had to fix.

So to answer your statement. I think it is ok to be jumped by other batteries as long as they have a good battery and not a crap one?

 

I have read the whole thread and since I went through a similar adventure, I would like to say a few things.
Per the symptoms you are describing, your 12v battery is near the end of its life. The similar happened to me. I lost half of the info screen. I have done some research and people reported a similar thing. I then did further testing by measuring the voltage with the headlights on (this is a very good way to load testing your 12v battery) and my battery was hot. I replaced it and the car came back to life.

Some people here will swear that you need to get a special battery for your Prius (the ones that cost around $200 or more) but the reality is that you can pretty much drop in any 12 volt lead acid battery and it will do the job. That battery does not provide power for the starter (MG1) so you don't even need a high discharge rate (CCA rating) battery unit. Technically a simple 12v lawn equipment battery will have more than enough juice to start your Prius. I am not saying go get that for $40. Just use your judgement and decide.

A 12 volt Prius battery (considering it isn't abused) can go 7-8 years easily. My battery (the original one) lasted 9 years. So if yours isn't that old, you may try to recondition that battery with a specialty chargers (the ones that does desulfation charge). I do not thing by constantly jumpstarting, you will eventually bring it back.

In anyways, good luck and let us know how you ended up.

 

You could probably just start the car with a strong set of AA batteries. But it is not going to last as long as the AGM lead acid battery.

Overall the car is pretty trouble free. I'd recommend spending the money on the proper battery.

 

A regular lead acid battery will work, but will release toxic fumes will fill the trunk, and the cab.
And you, and anyone else in the car, will breath them. Hopefully, you won't be driving when you get sick
and cause a crash and injure or kill some innocent person, or people.
But use whatever you want.
WHY would they use a $200 plus battery when a $50 one would work?

 

Ha-ha! What kind of toxic fumes? My $65 AGM battery does not release toxic fumes. A $200 battery is more profitable for dealer parts departments.

 

I was refering to "iskoos": "Some people here will swear that you need to get a special battery for your Prius (the ones that cost around $200 or more) but the reality is that you can pretty much drop in any 12 volt lead acid battery and it will do the job."

 

where do you get a $65. agm vented battery that fits?

 

Bro, buy a new 12v battery NOW, yours is kaput. you've already had to boost it / jump it how many times? How many more times do you need to get stranded before you'll replace the battery?