Hello all! I suspect my 12V is nearing the end of its life. My Prius is a 2005, with about 66K miles. I'm also in Arizona, so the poor thing is subjected to some nasty temps in the summer. Here's the symptoms: Occasionally going to the state of Ig/On (I think, like two power presses without pressing the brake) on power up. Made very sure I'm pressing the brake down firmly. It will generally start if I wait several seconds and re-press the button. It's done this about a dozen or so times over the past couple of weeks, but had never done so before. It is increasing in frequency. My canview is reporting a 12V system voltage of more than 13V while the car is running, which I believe is about right, so the car's end of it is probably fine. When in Ig/On, canview reports a voltage a bit more then 9V, which screams "dying battery" to me. I drive this car at least every other day, with trips of 30min or more. I figure I'm off to the friendly auto parts store, but I thought I'd check in here first, in case I'm missing something. Also, has anybody found the Optima battery at Costco? If so, how much was it?
Yes, I agree that your 12V auxiliary battery needs to be replaced. However, good luck finding a suitable replacement at a normal discount auto parts store. The price for the correct battery at your friendly Toyota dealer may be ~$160. The GS battery is made in Japan, so it costs more than alternative batteries made in China.
Prius Optima Aux shows pictures. You can buy the kit here: 12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007 and 2008 with free shipping This is a kit that replaces the Toyota battery with an Optima battery. I did this a few months ago and have been _VERY_ happy with it. I would HIGHLY recommend it, and I don't work for any of the vendors involved. I bought my battery from elearnaid above - it was the best price that I could find for the yellow top, and the kit made the install go very smoothly.