I like to drive with my headlights on during the day for added safety. But there are times when I forget to turn off the headlights by using the light switch on the turn signal. There is a secondary switch in the door. When it operates properly when you open the door the headlights turn off. When it does not, they won't and the start-up battery gets drained. With my limited research I discovered that the Prius had headlight problems but with the HID upgrades but not my specific problem. I also researched about replacing the start-up battery but found that nobody carries this. My issue is that it seems that leaving the headlights on for an hour should not kill the battery.