Maybe this has been answered, but couldn't find it on search...is there some sort of battery drain when hatch is raised, even though the courtesy light has been manually turned off? Seems like I read something about this recently, and don't want to damage the 12v if it's true...
You get the read light on the dash that says a door is open... Other than that their shouldn't be any other reason for additional power drain....
The door lights go on. They are incandescent, which means they draw lots of power. There is no way to turn them off.
The hatch latch switch is an input to the Main Body ECU, so at the very least, it wakes up the Main Body ECU, resulting in a draw even if the lights are not on. What I do when I need to leave the hatch open for an extended time is to flip the latch closed using a hook-shaped tool. This turns off the switch in the latch so the Body ECU thinks the hatch is closed. I also place a heavy folded up towel over the hatch latch in case I forget and slam the hatch closed. To actually close the hatch, I have to remember to release the hatch latch first.
I accidentally left my hatch open overnight once. When I saw it the next morning, I was certain that I'd drained the battery. Turns out the Prius will turn off the interior lights after a certain period of time, so as not to drain the 12v battery.
Funny you should ask. I posted elsewhere about this, but... I was rear ended a couple of weeks ago. Drove the car home. Opened the hatch to look for damage, and then I couldn't close the hatch because of damage to the latch. I turned off both the dome light and the cargo area light, and figured the battery should be OK. 2 days later I wanted to drive the car to the auto shop and the 12V battery was dead. I was able to jump-start it easily, but I called a Toyota dealership to ask if the hatch being open could have drained the battery. As someone mentioned above, even if you turn off the interior lights, with a door or the hatch open the car's computer stays on, and it will drain the battery in ~2-3 days. Doesn't seem like a great design! But, it is what it is.
Rear hatch up for 2 days, interior lights switched off, no lights on inside that I could see and the 12V battery was too low to start the car. Had to jump start it.
Yup, any door/hatch open is going to be hard on the battery. Better have it assessed, say with an electronic load tester, and hook it up to a smart charger (3~4 amp range) for a full charging session, then see how it goes.
Have it on a battery trickle/maintainer. After about 18 hours battery is at 12.3V. Will keep it on for the rest of today.
True. Even with all interior lights off or disconnected, the drain is about 0.7A, so about 3 days will deplete even a healthy battery.
