My 12V Battery is dying

According to the Napa website that's a 70Ah battery; whereas Toyota specifies 45Ah minimum. So not sure what your asking? Does it not strap-down properly?
https://www.napaonline.com/en/p/BAT7548

 

Are the dimensions roughly the same, the fiddly-design Toyota hold-down bracket fits (maybe with a washer or two)? It meets or exceeds electrical spec's? Then it's "correct".

 

It does exceed OEM specifications; so the real questions is: does it strap-down and vent properly in it's OEM position? The 2023 Prius battery got moved back into the trunk; correct? If that battery is under the hood, you can forget about item #2.
1. If it isn't properly strapped-down; it can rock around, loosen and/or break connections.
2. It needs to vent properly, since it's technically located in the cabin. There should be a vent hose connected to the battery so it can vent hydrogen out of that compartment (by-product of charging) - explosive hazard.
If that battery doesn't meet either of the above criteria, you've got a very good claim against the dealership for something that will actually meet both those criteria. That would make it a consumer protection and safety issue claim.

Good Luck.......

 

Yeah, OEMs are Panasonic or some other Japanese brand, not Napa. You could hassle them to replace it, but most likely they won't budge because it's working and not defective.

 

FWIW, the Toyota designed battery hold-down bracket is incredibly intolerant of any variation in battery height. Just a mm or two, and the damn thing is rocking, requiring washer(s) under the bracket, or shims under the battery. Not sure why they had to be clever, the usual hold-down bracket style has long rods with a hook at the bottom that hooks down there, and generous thread length at the top, that a washer and nut have at least an inch travel.

 

I went to this site, the first hit in a search, and observed that the only difference between L1 and L3, dimensionally is the length. L1 is 207mm and L3 is 274mm. I went out to the garage and measured. 274mm MIGHT be able to be squeezed in there. (I have my NOCO trickle charger (I did that on purpose) in there. I have no idea what the bottom tray looks like and what they may have done to it to make it fit though. Perhaps someone else knows.

Did you take the battery out? It looks that way.

edit: On the other hand, whatever they did, you can fit a higher capacity battery in there now. I'm on shaky ground, but it looks like it's a maintenance free battery and the NAPA site says it's a flooded wet battery, so does it still need that drain tube?

edit2: I came up with this for the battery carrier. No idea if I'm correct. Perhaps one could just bend the right lip so it's flat. Still, would be very tight based on my measurements.

 

congrats on finding the issue. that sounds like a very unusual failure!

 

I've got to get up on this techstream. Is this is something official? If not, and it runs on some old laptop, how does it get updated for newer models? Etc, etc.

My basic searching came up with this. I hope it's not a Gen5 trend:
SUB-BATTERY MALFUNCTION INTEGRATED CAPACITOR (INTEGRATION CONTROL SUPPLY) | PriusChat

 

following....

edit: I hadn't noticed that. His was some kind of internal fault and yours is a general deterioration of the "sub battery"-is the sub battery another name for capacitor?

What's function anyway-a short term backup to the aux battery maybe losing voltage or something? Have you noticed any systems affected, like the other poster's adaptive cruise?

It'd be nice to see a system description, somewhere.

 

I'd try to negotiate with management and maybe file something with Toyota corporate. You pay for the part, they eat the labor cost. I'd also point out the non-OEM battery fix; what else did they not do by the book????
You don't know unless you ask......

FWIW: they're suppose to have a 3 year 36K mile bumper to bumper warranty and 5 year 60K mile power train. That component would probably covered under the bumper to bumper, because it isn't part of the power train.

Good Luck......

 

You've also posted to another thread, also a 2023 Prius - I'd ask Toyota corporate if there's a TSB or batch issue with that part run. Where's there's smoke; there may be fire.....

 

Crazy. 1700 bucks.

So the "sub battery" is a capacitor for "just in case"? Maybe they saved a couple pounds a larger 12 v battery would weigh, and design It so it stays charged, lol.

Used car? I wonder why the large battery was put in (by the previous owner)?

 

More than likely it's a kick-starter/booster for when everything powers-up at once. Kinda like the starting cap. for your home AC compressor motor. It smooths out the sag in voltage; so that the ECU's are happy and the sensors don't send false information.