I have a couple of 2007 Prii, one put into service in Dec. 2006 and the other in Aug 2007. Both have the original 12v battery and both have about 30K (low mileage!) on them. Given the hassle that others have described when the 12v battery dies (and NOT wanting to jump the cars to get them into having the battery replaced!), I'm thinking of replacing the batteries on MY schedule rather than on THEIR schedule. A variety of posts have suggested the the 12v battery tends to last about 4-5 years in "moderate" climates. Is it the elapsed time or the elapsed mileage that counts? My 30K in ~3-4 years is less than some folks put on in 1 year!
It's both. Time is not kind to batteries. Nor is deep discharge and low or high temps. Sometimes low mileage equates to short trips. The Prius has a low charge rate and this can equate to a constant low state of charge when driven short distances. Electrical parts have a wide range when it comes to their failure date. On your two cars, you might get 5 years on one battery and 6 on the other. The question is if you plan to keeps the cars forever or will you just be needing ONE battery replacement before you trade them in. If it's the latter then the total cost is the same whenever you replace them. I, like you, plan to replace my battery on my schedule (5 years is my best guess).
My policy is to replace the 12V battery on my schedule vs. waiting for it to fail. A low odometer reading is cause to replace the 12V battery more frequently, unless you use a battery tender or a battery charger periodically to maintain the battery charge. A lightly used car means the 12V battery has greater opportunity to discharge and the lack of sufficient driving time means the battery remains in a discharged state, never having a chance to be fully charged. If you drive 10K miles per year that would be "normal" usage. If you drive 5K miles per year then I would definitely recommend using supplemental means to keep the 12V battery charged.
Thanks all for your responses. I drive about 7.5K/year Based on your comments, I think I'll replace the battery in my Prius as it moves into it's 6th year now.
There is a way to test the battery. http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html Why not change it out when it starts to fail?
When I lived in CA with moderate ambient temps, my personal policy was to replace the 12V battery at 6-year intervals. For owners who live with winter snow or who don't log many miles I suggest 4-year intervals to reduce unscheduled downtime. I now live in southern AZ and am not sure to what extent the hot summer weather will erode battery service life. For my cars that are lightly used, I will fully charge the 12V battery 2x a month or so.
While I think putting your battery in a condom is overkill, yes, get a date with a Optima D-51 battery. She will not let you down!!!
What about the Red Top Optima, I know redheads tend to be cranky, which would explain the higher cranking capacity. P.S., a nice razor is a handy tool to have!
Optima doesn't make a Red D51 - only a yellow one. (I knew I could count on you guys to take this thread straight into the gutter!)
We have an 06 Prius with 26,000 miles & wonder where to buy a battery other than the dealer & at what price ? Our original battery is doing fine but it is only a matter of when. Any suggestions ?? Thanks ! Bill in FL
AFAIK the Optima battery mentioned in many posts on this forum is the only alternative. Folks here seem to swear by it, though I have no personal experience with it.
Here is the address for Elearnaid the only source for a complete kit Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10
