Will interior lights kill the engine if left on for too long?

[Dintu]

This is probably a dumb question but the other day I accidentally left my interior lights on when I went to work. When I came back to the car 5 hours later I noticed the light was left on although thankfully it still started up fine.

I keep my headlights on 100% of the time since they automatically shut off after thirty seconds when the engine is stopped and I don't have to worry about forgetting to turn it on/off however the interior cab lights don't work that way. So now I just leave the interior lights set to "door" to avoid accidentally leaving it on.

 

[ceric]

5 hrs should be OK.
Leaving lights on just drains the battery. It won't kill the engine per se.
However, if your battery is old (not now, of course), and you keep draining the battery, the life span of the battery will be shortened.
Try not to do that....

 

[concept]

It also depends upon the type of lights. Interior LEDs consume a small fraction of the old incandescent lights. Most newer vehicles, like the 2014-2015 Mazda 3s use LEDs.

 

[WuCheng]

Well i left my interior lights on by accident one time for 2 days because i wanted to quickly look over the user manual and it still was fine , it didnt kill the engine or battery in that case so 5 hours is fine , and you also set it on door so its not like you intentionally always leave them on

 

[GrasshopperCO]

It's no big deal. It will drain the battery over time (and by time, as WuCheng pointed out, I mean a long time), but if you're able to start it, then the alternator will just charge the battery up again. Do it habitually and you may shorten the life of the battery, but a single incident isn't going to hurt the engine or the battery at all.