2011 Prius Base - 12v Battery replacement

This has been hashed out here the last 15 or 17 years or so so plenty of reading 12 volt batteries are pretty subjective so it was always that and now they are extremely costly versus 20 years ago so there's always that warranties are prorated as always so there's always these things and it's a good game at best I've had good luck with the die-hard AGM looks like it's got blue water or something on the front of the label. Generally problems with the 12 volt are usually the owner's fault A flooded battery tray that's frozen in the winter and leaving stuff on You can't blame the battery manufacturer for human shortcomings.

 

Replacement of the 12v battery is no different than any other standard car.

Yes, you will lose the radio station memory.

I will be buying a battery from Walmart when my present battery goes bad. I am hoping that will be in 2 to 3 years from now.

 

As opposed to a "normal" car, it's a little different because of its location.

If you've got a bunch of stuff in the back, you might have to pull it out to get the floor panel out.

Because it's buried down in a hole, you don't want to drop a socket or one of the screws too. (The first time I changed out the battery in my Gen 2, which is similar, I dropped one of the screws or a nut. Finding it and digging it out turned out to be the hardest part of changing out the battery).

I found it's easier to remove the bolt holding the ground lead to the body, then removing the negative battery clamp when you've got the battery out to be easier than removing the negative battery clamp when the battery is in place. That may be just me though.

The cover over the positive battery clamp was also a little bit of a trick to figure out how to get it opened. Still, not much of a problem.

You may also find the vent tube to be something you're not used to. Keep from crushing it when you put in the new battery. If the tube is stretched out and won't stay on your new battery, maybe you'll need to trim just a little bit off (1/4" to 3/8"). If your new battery doesn't need the vent tube, maybe tape it up where the next person can still use it.

Like @Tombukt2, I got a DieHard AGM the last time I changed out the battery. I also changed out the 12V battery in my 2019 Prime and just for the heck of it I called the dealer. They had one in stock for less than any of the replacements, and it had a better warranty spec than anything else I could find. If I needed to change the battery in my Gen 3 today, I'd probably see what the price/availability would be from the dealer too.

I got a Super Start (O'Reilly brand) battery for my Gen 2, and I wasn't impressed by how long it lasted. It was still under warranty, but when it needed to be replaced about 2 years later (3 year warranty), I took the pro-rated refund and bought the DieHard from the Advance Auto across the street.

That's all I can think of.

 

The cost is insane. Especially since the Prius battery seems to be about 1/3 the size (capacity) and 3x the price of the batteries I've put in other cars. They have the same chemistries that are used for other cars, so it bugs me that they're 3x the price.

 

The walmart batteries are quite good, been using them for years in all my vehicles (inc the prius).

 

In addition to radio settings, trip odometers, and some engine performance values (your mpg may decline after reset), if you have the driver side power window Auto feature you will have to reset that also. Instructions are in your owner manual.

 

The window auto-up may or may not need recalibration. I've purposely disconnected the 12 volt neg (doing brake work) and it was ok after. I did lose trip meters and radio presets, and displays set to default. Also, the next few start ups, the car rev'd up unusually, I think recalipbrating something, maybe throttle response.

With battery swap I hooked up my jump pack with a special cable, that has cig lighter plug at one end (plugs into my jump pack, and an obd connector at the other end, with just the prongs necessary to supply 12 volt. These cable typically have incicator lights to confirm you've got good connection. Google memory saver cable for that.

Anyway, when doing battery swap, the one hassle I encountered: the $#&8?! Toyota battery hold-down bracket is absolutiely intolerant of the slightest variation in battery height. My replacement battery (Optima Yellow Top) was maybe 1 mm taller, and I needed to shim the bracket with a washer to compensate.