Hi everyone, First post, I've had my 2005 Prius for about a month now, absolutely love it. I had a question about the 12v battery. I have a battery and charging monitoring system. I see that my battery is usually around 11.5 to 11.9 when it's in auxiliary mode, and jumps to 13.8 to 13.9 when I turn the car on and while I'm driving. My commute is usually around 10 to 20 minutes each time. Never had a problem with starting the car, all windows go up and down fine, no dim lights or any other warning lights. I know the battery was purchased new June 2013. I'm wondering if it's time for a new one for preventative maintenance or if I'm fine with this battery for now.
I believe it's a direct fit, no modifications. And I don't have an external battery reader, would rather not buy one if I don't have to!
I don't know about the 2nd generation, but in the 3rd there is no "auxiliary" mode, according to Toyota's terminology in my manual. In what they call "ACCESSORY mode," there's significant drain on the battery, about 1.5 amperes even with every accessory off. In "ON" mode, it's higher. Reasonably accurate voltmeters are cheap.
To be on the safe side never use the aux or accessory mode, I think those modes main function is to spur the sale of 12 volt batteries.
