12 volt battery failing to start the car

I guess, that means you don't have Gen4 or Gen5 Prius. I had Gen3 Prius, but never even bothered to find out where the 12v battery was located. If I had to charge it then, I would have been totally lost not finding the 12v battery under the hood. LOL

EDIT: I just found out that the Gen5 12v battery is back in the trunk again. I thought it was under the hood as in the Gen4. Sorry for the confusion.

 

Well, this is a surreal, somewhat detached from reality thread... Kind of cute that Once-Twice is just happily ignoring the nonsense.

 

Oh, did the Gen5 Prius relocate the 12v battery back in the trunk once again? I've never owned or driven Gen5... I assumed it was similar to Gen4 PP in that the 12v battery is under the hood.

 

Yep, it's back in the trunk again. Probably due to space constraints because of other changes they made.

 

I just ended up following a couple of videos on the RAV4 Prime with the battery location.

It’s more convenient to go into the engine compartment. But most seem to be connecting to the battery directly.

 

Thanks for the info. Now, I know why the question was asked. BTW, does that mean the Gen5 12v battery is once again AGM?

 

Right rear corner, covered. Sticks up above the trunk floor a bit.

 

Sorry for the confusion. I don’t think it’s an AGM battery.

 

Just to add an extra bit of confusion to the thread, gen5 Priuses with the old 1.8L 2ZR engine still have the battery in the front. So that means a Prius delivered to Texas has the battery in the back, while a Prius delivered to Mexico has the battery in the front.

 

Good idea!
Maybe if enough owners complain about the abuse the 12V battery is going through and what some owners have to go through to not have the 12V battery die an early death.

It should/could be a Free SW update to tell the system to keep the 12V topped up when the car is plugged in.

 

It surely is an AGM if it's located in the cabin of the car (no venting),,, unless it has an old fashioned vent hose going through the floor to the exterior.

 

It's not AGM, it has a vent hose.

 

What is the TIS ? I have seen the acrynum (sp?) a few times. Would like to know ?

 

I thought it was related to this, but always think of it as Toyota Tech Info. Anyway: Technical Information System. Explained in intro:

https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page&goto=https%3A%2F%2Ftechinfo.toyota.com%3A443%2Fagent%2Fcustom-login-response%3Fstate%3DAa3pxKXpGm2RDIUVHK4O2eulszU&original_request_url=https%3A%2F%2Ftechinfo.toyota.com%3A443%2F#:~:text=The%20Technical%20Information%20System%20or,1990%20and%20later%20Toyota%20products.

Some folk aren’t happy till simple stuff is inflated into three words, then distilled to an obscure acronym.


Don’t get me started ‘bout ICE…

 

Technical Information System

It's part of techinfo.toyota.com. It's where Toyota puts all their repair manuals, service campaigns, wiring diagrams, new car features, specifications, etc, etc., etc. It's the same system Toyota dealership technicians use when fixing the cars. It's a paid website. I actually pay for a yearly subscription for now($480/year), but you can also buy monthly($90) or a 2-day pass($20). Those are basic levels; to use the diagnostic software you pay much more($65/2days or $1295/year).

TIS is what Toyota calls it, so TIS is what I call it. I've learned through (hard)experience that it's better in the long run to learn the Toyota naming conventions and get used to using them. It eliminates so much confusion and simple errors, especially if you end up eventually needing to talk to a Toyota employee. If you give them the proper terms, everything goes so much smoother and quicker.

 

Thank You !

 

Thank You !

 

2023 Prius Prime. My battery died on me this morning. Got it towed to Dealer. I charged it up full on Wednesday . I unplugged the charger right after full. I did not drive it all day Thursday. When I went to go to work this morning Friday the battery was dead. All the lights came on blinking and the wiper blades turned on but ran very slow. The tower had to charge my car up for 5 minutes before I could start it and drive out of the garage to but on the flat bed. Not sure what happened but the dealer said everything is checking out as good. They are keeping it overnight for observation.

 

This is feeling reminiscent of the 2020 RAV4. Those also had a problem with killing the battery. The issue turned out to be a bit of bad code in the DCM. That debacle took Toyota over three and a half years to sort out.* Hopefully this problem is solved quicker(although finding a bit of intermittent bad code is probably like finding a needle in a haystack in a snowstorm for Toyota).


*The problem was first spotted in late 2018 or very early 2019 during RAV4 testing. Toyota tried multiple software fixes throughout 2020 and 2021 before finally landing on the finished solution in mid 2022.

 

I know what is wrong. Your 12V lead acid battery is toast.
Lead Acid batteries can't be left in "0 Volt Land". They chemically die.
Tell you dealer you want a new 12V battery.
Toyota needs get off their azz and updates the SW.

An EV or PHEV driver should not have to dik with unplugging the car for no good reason.
These cars should be plugged in for Thermal Management reasons. The HV battery pack likes certain temp ranges.

Good Grief....
Nothing like learning from you mistakes....
Hang in there Gen5 owners.