Will this bosch aux battery be the right replacement?

How did you arrive at this battery? Try going to Pep Boy site, shop batteries and enter your car data, see what it comes up with? I recall they stock Bosch, and do have appropriate battery for third gen at least.

Regarding your pictures: doesn't appear to be AGM type, and the posts look too big, but yeah, check out the Pep Boy site.

 

Positive and negative terminals in that battery seem to be the wrong way around for gen 2 Prius!

You can’t install the battery backwards in the Prius so that just doesn’t fit. Different size battery posts could be used by changing battery terminals but for reversed terminals there’s really no fix.

 

A group 51 battery will fit as long as you change the terminals to fit SAE posts. A group 51R will have the positive and negative terminals reversed and will not fit without longer cables sized for SAE posts. You should be able to find the correct S46B24R battery with JIS posts for about the same price as either the 51 or 51R AGM batteries since they are the same size.

 

My experience as a Toyota tech is use OEM but stray from Optima. Bosch should be good but as long as its AGM flat plate, 325 CCA, and the terminals are where they are supposed to be then you should be good. You will know within a month if you messed up but we do see a lot of the Yellow top Optimas which are not the correct type for the vehicle.

 

what will happen within a month?

 

You will start to see the battery degrade and start causing weird issues to your vehicle. Symptoms like your lights will start flickering, your vehicle will at times not shut off or not be able to turn on etc. I ve seen weird issues with non OEM batteries but of course I work at a dealership and that is where some people bring their vehicle when desperate or just not getting the for sure answer on balck and white written Toyota warnings lol. And yes check the 12V health but they may be related. Remember that 12V controls a good bit and has a specific wire that runs all the way up to the engine bay from the back.

 

Whats whong w/ you?

It is your car and you can add whatever you want, but the manufacture did things for a reason!
The factory battery was an AGM battery for a REASON.

1) The battery is inside the passenger cabin.
2) AGM batteries don't have liquid sulfuric acic; a severe right rear impact will hit the 12V battery. Your choice of a traditional wet cell 12V battery could make things worse, beyond the collision itself.
3) AGM batteries are able to be run down better w/ minimal effect, unlike wet/maintenance free type batteries.
4) The prius 12V battery does not crank the engine, so CCA is meaningless to the Prius.
5) AmpHr is more meaningful for the Prius. The factory battery was a 45AmpHr battery. The image of the bosch wet cell batery you are considering is only 25AmpHr. You are loosing 20AmpHr! if your car has SKS, you'll be miserable with this battery. Too little capacity; keep a 12V booster battery in the car w/ this under-reserved battery.
6) How much is this wet cell Bosch?
7) Surely you can afford $143? Exact fit. AGM. JIS posts (I believe). 45AmpHr. Vent tube hole. 4yr straight warranty, no proration.
Car Batteries | Auto Batteries For Trucks & SUV's | Pep Boys

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We say CCA but 325A is what is on the battery and yes you are correct not a cranking battery but it does power the System relays and certain accessories and does need a certain amount of voltage ready. Everyone go with AGM flat plate. Not wet cell. But as always if financial frugality dictates your parts replacement then hey Ill see your vehicle when you come in to the dealership saying your vehicle wont start and try to take it back to the store you got it from because you didnt want to pay the extra $50-100. It is always up to the customer who we try and educate but as always its not our vehicle. Its your vehicle. Your decision.

 

huh, i thought it was the other way round.

 

ok.

 

Bosch 51R: $121.49, incorrect battery, 3year straight warranty
Bosch 51(AGM Prius): $142.49, CORRECT battery, 4year straight warranty

Sad state if OP can't afford the difference of $21 + tax.

4 lattes or 3 McDonalds BigMac meals would cover this difference. ​

Bosch Premium Performance Battery Group, Size 51R | 9998218 | Pep Boys

 

Erik - I went with the Bosch AGM flat plate in my 2007 Prius (226k miles), and everything was fine for three trips afterward. Starting with trip four since the replacement I have intermittently had the dark combination meter issue upon start up of the vehicle (classic symptoms, including car will not turn off via normal sequence when the panel is dark).

From your experience, could the 12V battery replacement be related to the combination meter starting to go dark periodically, or is this just an unfortunate coincidence?