Hi there My 2006 Prius battery runs down regularly overnight. It seems to be something connected to the immobiliser and/or the interior lighting. Has anyone experienced this or have a solution? Cheers Simon
I presume you are talking of the 12V battery? If it's the "traction battery" ignore it. The charge display is unreliable in those situations as temperature affects the reading as well. If it's the 12V, check the light switch in the hatch area and the two in the cabin. They are all three position switches, labled OFF, Cabin or door, and ON. You want OFF or Cabin/door. If you're wondering if one of the door switches is malfunctioning, make sure the overhead light is on "Cabin/door", close the door, move about 10' away and watch to see it go out. If it goes out you're fine. Finally, make sure the hatch is -fully- closed (slam it shut). And as posted above, if your 12V battery is the original, it's probably at end of life and will self discharge due to plate leakage.
Attempting to lock the car will remind one of common battery-draining situations. If they exist the car will give a long warning beep instead of locking. If the 12V battery has been killed once it is now at death's door and should be replaced before you get stranded.
