Two days ago, I left my trunk open and when I try to start the car the next day, the battery went dead. My question is does the little trunk light have a timer that will turn it off or will leaving your trunk open deplete the battery? I had the trunk open for a whole day before and it was fine, but this time....

 

I leave my trunk open when I monthly charge my battery. I noticed that after aprox. 30 minutes both trunk lights turn off, so yes it does have a timer. However, I cannot guarantee that with it open there's no other system pulling the battery empty, like the alarm system perhaps.

 

Yes, as Bob stated, the light will go out on its own (not sure in how many minutes}. Since it worked before, perhaps your timer malfaunctioned.

My question is, why do you leave your trunk open?

 

I didn't bother to close the trunk after I took out the grocery last time, because I need to put the grocery bags in, and my car is parked inside the garage.

 

I believe that I am correct in telling you that leaving the trunk open will cause the automatic-headlights-off to not operate. The headlights on will definitely quickly deplete your battery.

 

Maybe that's why! Anyway, from now on I will keep the trunk closed for Good. Luckily I have a good battery charger and my battery is still good.

 

There are a number of things I don't care about with my wife's Porsche Panamera (but that's the car she wanted), but I must say I like the hands free trunk closing. You simply wave your foot under the rear bumper and the trank lid opens or closes.

 

Taking batteries below 50% State-of-Charge often damages them and shortens their life. You should test your battery and monitor it closely.

 

Flattening a Battery and leaving it discharged for a long time, or freezing it, can definitely do harm by sulfating the plates. Having it go flat overnight and charged the next day isn't the best thing for them but it will not do any permanent damage. Having a smart charger that "Conditions" the battery helps a lot in their longevity.

 

I accidentally left my trunk open for a few hours. When I noticed the light was off so it does have a timer, but I was also unable to close the trunk with the push to close button, had to manually close it😓. I it did start without issue.

 

I know from experience; I had water getting in my trunk and left it open in my garage to dry out. After about 20-30 min it will go off but, don't go near the car with the key, or it will turn on again...

 

My charger has a REPAIR function that works great. I accidentally flattened the battery 2x and then I used the repair function overnight and the next morning the screen shows OFF with full bars, then I switched it to the CHARGE function but it only shows 80% charged and 12.4V. I let it charge to full and then it showed 12.9V. Looks like my battery is still good. i got this great charger from Amazon for only $24.