Bed Plug - Constant Power?

i need to run a fan for the hot mornings when i sleep in the truck, and a portable radio for the drive in movies. how can i keep the outlet in the bed on all night? a cigarette lighter plug wont cut it. and im absolutly useles when it comes to electrical stuff. i learned that if i turn the truck off while in neutral the outlet stays on but i dont know if it will drain the battary if i had a fan running all night.
and im as useless as tits on a bull when it comes to electrical so the more simple the better cuz i have no idea what you guys are talking about in this thread

 

I loved the idea on this thread,l but didn't want to totally drill out the side of the compartment in the bed, especially with electrical connections being exposed in the fender well.

So instead, I bought a different panel, built a box, and added a low voltage cutoff.

The project took way longer than it should have, but I'm anal about electrical work and building the box took longer than I had expected. Added an audible alarm too so I can hear when it gets close to the voltage cutoff tripping.

Box fits into the small cubby next to the power outlet. Can't wait to wire it to the battery and give it a go.

 

These new coolers must be a lot more efficient than a few years ago. I left one plugged in over night and the next morning the battery was flat as a pancake. The battery wasn't new, but it wasn't old either.

If you really can run a cooler over night I might look into getting a new one.

 

What did you make that box out of? 8guage to the battery as someone else mentioned?

 

Yep, 8ga to the battery. 12ga inside the box.

Box was made out of thin plywood. Used black silicone to seal all the inside seams.

Super snug fit in the cubby, on the verge of too snug, but it still allows the door to close. Exactly what I wanted to keep it from rattling around. Zero free play.

I got super lucky because I never took any actual tape measure measurements, I actually cut pieces of cardboard to fit inside the cubby and then mocked the box down slightly smaller from that. It just happened to turn out really really well.