Stock Tray for 12v Auxiliary Battery ?

That looks stock to me; it's been a while since I was down in there. You need to look for a 51R case size battery, which needs to be shimmed about 1 inch on the bottom to bring the posts up to terminal height. A cheaper alternative, which I am using right now, is a U1R lawn tractor battery (https://www.batteriesplus.com/productdetails/sliu1rxhd). You will have to convert the spade lugs to the standard SAE posts, which I did with a kit from East Penn (Deka 02033). The conversion bolts into the holes in the battery lugs; you may need to ream out the holes, depending on the bolt size in the kit. (I had previously converted the OEM positive clamp to an SAE clamp, and replaced the ground cable.) BTW, the U1R also needs the 1 inch bottom shim, and then you can use the original hold down bracket as well.

So far the U1R is doing the job. We'll see how it gets through the winter. Fingers crossed!

 

It's the stock tray. Not sure about the battery terminals, they might be a bit larger than OEM, but hard to tell.

I have a NAPA 51R in my '01 and did need to modify the tray to make it fit.

It's important to get an AGM replacement which is why they tend to be more pricey. The good news is these batteries can recover from being completely discharged better than standard lead acid.

If the car sits for more than and couple weeks the 12V battery drains (I think there's something like fuel pump that kicks in now and again even when the car is turned off). If the battery drains too far there's not enough voltage to close the contactor to the HV battery so the car won't start.

Before replacing the battery, try recharging overnight with an inexpensive trickle charger. This will top off the battery without the risk of damaging it.

 

I beg to differ about the need to use an AGM battery. I've used conventional lead-acid batteries in my '02 ever since the OEM Panasonic died, with never a problem. Please explain your statement in re: AGM!

 

I agree an AGM isn't required, but at the very least a sealed battery should be used since it's in the trunk. The battery in my Highlander Hybrid is under the hood and the OEM replacement isn't an AGM.

 

You pays your money and you takes your choice. I'll stick with what I have described above (the U1R lawn tractor battery with converted posts and clamps).

 

The OEM 12v battery came with the smaller diameter posts and fittings. I converted the positive clamp to SAE (that involved unbolting the original clamp and bolting on the replacement; basically a simple DIY job, some reaming required on the replacement to get a correct attachment). I simply replaced the ground cable with one from the auto store. I've been through several 51R batteries (Deka, Interstate, DieHard, etc.) with this set-up. Back in March the Interstate gave up, and that was when I made the switch to the Duracell U1R, which I had been contemplating doing for quite some time anyway. Years ago I had purchased the conversion SAE posts (Deka 02033) at the local Sears Hardware (remember those?) in anticipation of possible future need. Well, the future came, as it has a way of doing, so when the Interstate crapped out I was ready. The U1R was installed at the end of March-beginning of April this year; the battery has a build date of 3/23, so it's fresh as can be. I expect it to last at least as long as the Interstate (five years +), given the charging protocol of the Prius and the sheltered location in the trunk (if it doesn't explode or leak and kill me, wink-wink).

BTW, all of this conversion business is fully reversible should the occasion ever arise, which I don't see happening.

I sure wouldn't pay those exorbitant prices that the dealer quoted! That's just ridiculous!

 

I've been using the lawn mower batteries for awhile. Get them at Walmart for about $30 now. 6-month warranty - just take it in before then and get a new one. Just make sure you get the one with the terminals in the right place. The car's clamps won't reach a terminal on the wrong side.

I didn't need a kit to make the terminal connections. I did have to take the stock terminals apart a bit, IIRC, there's some plastic parts that came off. It looks a little cluggy, and you gotta spread the terminal clamps slightly to push them on the terminals, but the stock bolts and nuts go through the hole in the battery's terminal and works fine. You can put the clamps back together later if you go back to the other batteries.

 

There’s a couple of reasons for using AGM (stands for Absorbent Glass Mat IIRC), with a battery technically in the cabin: it’s less likely to vent hydrogen, and to spill acid in a severe crash. That’s why Toyota specs AGM. Both concerns could be overblown, but anyway that’s the story.

 

Lawyers have never heard of the term "overblown," lol.

 

More like "overkill," IMO.

I drove a '64 Beetle for many years. No masterpiece of engineering that, and guess where the 6v battery lived---under the back seat!

 

There could have been a lot of lawsuits since '64

 

No doubt. The battery location was the least of VW's worries. No brakes, no power, no heat/defrost, front gas tank: a host of liability issues arising from poor engineering. Yet it sold in the millions. "And it was so cute...."

A rolling liability machine.

 

My folks 58 bug had no seat belts.

 

That's nothing; my '64 didn't have any seats! (Well, that's how it felt, anyway.)

 

My '68 had one of those Middle Eastern bongs mounted between the front seats with 4 hoses, one for each passenger.

 

Lends new meaning to the expression "Ridin' high!"

 

Not sure about "new," lol. That was a long time ago - '73.