Gen 1 prius 12v auxiliary battery wont fit

According to the website (https://www.carparts.com/search?q=odyods-agm28mja), it is a 51R case size, which should fit just fine. I've been using 51R (the "R" stands for "reversed terminals," with the + post nearest the car's positive clamp). I don't know what size terminals posts the Odyssey uses; you may have to switch out the car's clamps if it's SAE (standard American) posts, as I did years ago on my '02 to simplify replacement, with more choices of domestic batteries. I'm currently using an Interstate brand. You don't have to pay Odyssey prices to get a working 12V battery in your '03!!

 

welcome!

if you need a mechanic to swap batteries, there's not much we can do to help.

if you want to learn, you've come to the right place. remove the old battery, and bring both to carparts, so they can see the reversed terminal problem and find the right battery for you.

 

Just to clarify---Timg1's 2003 Prius does need the 51R battery case size, i.e., the one with the reversed terminals. I'm guessing that there may be incompatibility between the Odyssey terminal posts and the car's battery clamps. I know that other owners have used the Odyssey battery---how did they address the problem? Can anybody out there help here?

BTW, the battery pictured in the link to carparts.com that I posted above does NOT have reversed terminals, so if that's the exact one that Timg bought, it's been misrepresented. But to state again: you don't need to pay Odyssey prices to get a decent 12V battery for the '03. Any 51R case will fit. No need to pay extra for AGM, vented ports, and other luxuries. I've used normal mid-quality batteries in my '02 for 20 years now, having switched out the original + clamp, and using a standard SAE grounding cable. In the early history of Prius there was a lot of talk about hydrogen gas explosions and acid leaks and other scary conjectures if you didn't have a vented battery or operated the car upside down, etc., etc., but IMO these possibilities are vanishingly small. My current Interstate battery is into its sixth year and still going strong.

 

Don't think you can "bring" anything to carparts, they're an online retailer, not an AutoZone.

According to the product info in the cited link, the Odyssey does have SAE terminals, so Timg's mechanic should be able to convert Prius' clamps. Heck, even I could (and did) do it, and I ain't no mechanic!

 

Sure enough, that battery isn't going to work. I'd return it ASAP.

To save some time, you could just change out the OEM grounding cable for a new one with a proper SAE clamp on it. These are available at the usual parts stores. When you install your battery, you'll probably have to shim it underneath, as I did mine, with a one-inch thick piece of wood. Also, I replaced the OEM hold-down clamp, which didn't fit over the new battery, with a short cargo strap.

 

Toyota’s style of securing 12 volt batteries is very intolerant of the slightest variations in battery height or width. I was replacing a Matrix battery a few days back; and both these variations were a factor.

The bracket across top of battery sat directly on the car body at one end, and new battery was maybe 1/8” taller. Luckily I found a shim washer in my pocket change, could have used a couple.

Then, the bracket has 2 WELDED tangs on underside, to restrain the battery laterally, obvious a VERY set dimension between them. Luckily the new battery was slightly narrower, about 3/8”, so it was at least able to fit between the tangs, but lateral support thus compromised.

Honda, in comparison, uses the hook-ended threaded rod and nut hold-down brackets, much more accommodating of battery dimension vagaries.

Returning the old battery (for core charge refund) I noticed this example of the hook-ended threaded rod for sale:

 

i think you did the right thing. i paid $210. plus tax a few years ago for an oem, so $250. these days sounds reasonable.

 

I'm not sure what the last couple posts are doing in a thread about the 12 volt auxiliary battery.