You can easily check out your battery status/charging system using the MFD in maintenance mode.
No tools required. - Get your Prius into "Accessory Mode" - Press the power button without touching the brake pedal.
- Put the MFD into "Maintenance Mode" - Press and hold the "Info" button on the MFD while turning the headlights on and off 4 times.
- Press the "Menu" field on the screen.
- Press the "Signal Check" field.
- The 12v battery voltage will be one of the items listed, it should be above 12 volts. If it is lower, either the battery needs replacement or the charging system is not functioning correctly - see step 7.
- Put a small load on the battery by pressing the power button again without touching the brake pedal. The voltage should stay above 12v. If it drops significantly, you need a new battery.
- Now get your Prius into "Ready Mode" - step on the brake and press the power button. The battery voltage should immediately rise to 13.8 volts (Your Prius uses constant voltage charging). If it is lower, the battery will never charge; if it is much above 14 volts, your 12v battery will get cooked.
- Shutting the car down will reset the system back to normal operation.
If you need to get a new 12v battery, you can opt for a dealer replacement or get a better battery at a lower price at:
http://www.elearnaid.com/12vo1topraub.html
and install it yourself.
JeffD
Anyone know whether same procedure works for Camry?
I may try.
And: Are we sure that 15 v. would be too much. A lot of aux. auto battery chargers would do 15 v.