Lights left on

it will put some drain on the 12 volt battery, how long do they stay on?

 

Short answer, no. I always leave the headlight switch in the "on" position. Lights automatically turn off within 30 seconds after ignition "off."

 

Sure it does, the question is, is the amount anything to fuss about?

The headlights are around 55 watts, if I remember right. There are two. So leaving them on for 30 more seconds after you leave the car drains the battery by an extra 3300 watt-seconds. 3600 watt-seconds would be one watt-hour, so a little bit less than that. One kilowatt-hour, which is a thousand times that, generally costs around a dime, more or less.

Next time you turn the car on, the battery gets recharged by that amount within the first, again, couple dozen seconds or so.

 

Yes, of course; car is off, lights are on.

 

Once the car turns the lights automatically off, there isn't any meaningful drain happening just because the switch is in the "on" position.