I need to replace the 12 volt battery in my 2001 Prius. Do I have to buy a battery from the dealer or can I pick up one from the parts store?
You can get one anywhere, just make sure its the same overall size and has terminals located the same.
The original battery has a Japanese style, smaller terminal post so your options are: buy from Toyota parts department - most expensive buy terminal adapter and Miata battery - less expensive buy lawn tractor battery and fabricate terminal adapter - lot less expensive but some assembly is required and a trip to hardware store (is a lot more fun!) peel the "DO NOT REMOVE" sticker off; pry off the plastic cover strip to the filler ports; add distilled water to just cover the plates; put battery on charger over night; reassemble and test - way more cheap if battery tests OK (kinda boring but very inexpensive) GOOD LUCK! Bob Wilson
I would at the minimum get a sealed battery with glass mat technology similar to the factory spec's , here is a link for a non dealership source; 12 Volt (12v) Toyota Prius Auxiliary Battery for 2000, 2001, 2002, 2003 with installtion kit and free shipping to 48 states price; $ 133.95
If you are tempted to pursue a choice other than buying the correct battery from your Toyota dealer, or the elearnaid alternative suggested above, then I recommend that you carefully note the polarity of the battery terminals (Classic battery has the negative terminal on the left when the terminals are closest to you) and ensure that the replacement battery that you obtain has the same polarity. If the battery has the opposite polarity then you will have to install it so that the terminals are adjacent to the fender. This doesn't give you much safety margin if that fender is hit in an accident, and it is quite possible that the battery may be shorted in the impact. That could cause large sparks, etc which might add more drama than needed to the situation.
At least ask the battery price at a Toyota parts desk. Years ago they were very high, but there have been reports of more reasonable prices recently. This may or may not be related to the availability of direct-fit alternatives As always I will repeat the strong warning to never under any circumstances connect any 12 v battery to Prius with the polarity reversed. It will at least render the car temporarily inoperative, and at worst require an expensive repair.