Got a buddy with a 2001 Prius, his starter battery needs replacing and the fine guys at Kragen said any ol' 12v battery won't work, as a result I'm wondering what options are there as a google search for prius and battery as you can imagine brings up the wrong type of battery.
The basic problem is that the Prius battery terminals are much smaller than normal battery terminals. The easiest option is to buy the correct replacement 12V battery at the Toyota dealer for around $160. A harder option that can save money would be to find and buy a battery that will fit into the physical space available and has the positive terminal on the right hand side, when the battery is oriented so that the terminals are closest to you. However you will need to replace the positive terminal connector that mounts to the fuse block, and also replace the negative terminal connector and cable with a new connector and cable. Also note that the original battery is supposed to use absorbent glass mat technology; however some owners have reported their original equipment batteries were not AGM. If you install a liquid acid battery this may pose a safety hazard in the event of an accident that impacts the fender of the car where the battery is installed.
Or you can get a battery for a lower price from: http://www.elearnaid.com/12vobaforpr2.html Or for the newer Prius Model: 12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007, 2008 and 2009 with free shipping They also supply a kit with all the adapters you need for the installation. JeffD
I just replaced the 12 volt on my 2002 with the battery and kit from e-learnaid. Dealer wanted $300 for battery and install. I paid $135, and it came with great instructions to do it myself. (and I am no auto mechanic). It did take about 5 times starting the car to get everything running properly though, which happened to someone else, discussed on another thread.
Best price for 2005 Prius: buying a Starter battery, since size matches the Series 51 batteries. I got mine from Batteries Plus for $56. I also bought a standard terminal adapterkit with some washers and wing nuts because the Prius starter batt has "pencil terminals" ( about 5 mm in size) and just drilled out the pencil opening on the connection to fit to standard 5/16 inch to accommodate the Series 51 terminal screw through it.
Usually when this question arises, we have a long discussion about the necessity for a vented battery. All Prius so far have had that. Some but not all of the suitably sized replacements are vented. If you want to follow Toyota design to the letter, you will choose among the vented batteries. For unvented batteries you would have to decide for yourself if they represent an unacceptable risk.
