where to buy 12V battery

welcome!

what's wrong with a dealer?

 

The c uses a unique 12v battery. Others can be made to work but the one sold at the dealer is the only slam-dunk direct replacement I know of.

What's special:

1. Unusual size
2. AGM type
3. Hookup for external offgassing vent
4. Smaller posts with smaller terminals

If you can adapt another battery to that, you're set. Otherwise go say hi to the dealer parts counter.

 

if you're going to diy, call as many dealers as you are willing to drive to. prices vary, and some have coupons.
$400. is installed, and the battery should be around $200.

 

Look for Optima battery dealers in your area. Optimas used to be hard to find, but that's changing. You'll want the yellow top version that's made for cars that don't use the 12v to crank the engine. I believe their part # is DS46D24R for the C, but ask to be sure. Toyota has a different battery depending if you have smart key and navigation. Not sure if Optima does, but its worth mentioning. It won't be that much cheaper than the dealer, but you'll be getting a better battery.

But - if you haven't actually had your battery checked for CCA and volts, I would. Don't assume that just because its 3 years old that its like most car batteries and needs to be replaced. Prius 12v batteries last much longer because they don't have the strain of constanly starting the engine.

 

For example. I'm on my factory 12v still. 115k miles and 6 years of me owning the car. Bought it off the lot with 300 miles (they drove it 200 of those from another dealer) on Jan 2013.

 

@bisco's making a lot of sense.