Options for wiring to truck bed

I have a hard time grappling with electronics... I'm looking to install some accessory lights off my bed rack for camping/working by my truck. Looking for a trick to get the lights to work even when the car isn't running. I bought the truck used and it looks like the previous owner had some wiring for a topper that works but only if the engine is running.

Eventually i want to set up a second accessory battery, would that solve my problems?

 

You could wire a secondary battery but I don't see why for just some lights. Usually people get those for overlanding and helping run things like a fridge or whatnot.

Why not just wire the lights directly to the battery, and run them off a relay? You can switch them on/off from the cab or you could put the switch somewhere else.

 

That's the direction I'd like to go eventually (very slowly). The wiring that came with the lights isn't quite long enough to stretch from the battery to where I want it on the rack. Again I know very little but I've seen the same size wire at walmart I was toying with the idea of just splicing some in to make it the appropriate length.

The wiring already in the bed just seems like so much less work, is there a way I can modify it to make it work?

 

I don't know what wiring already in the bed you're talking about, but I don't know of any that is hot while the truck is off (well maybe one in the trailer harness). If the wiring isn't long enough, then yeah just extend it so it is. That's what I would do.

 

@mattgecko can solve your problem with spiffy under rail LED lighting.

Easy Peasy instructions included. Not to mention nice lighting in an out of the way place.

 

Do you have a tow wiring? Look at your tow plug.

 

See below for a write-up I did that may be helpful

You can follow the rock lights or reverse light section and replace the lights I used with the lights of your choice (and skip the section that splices into the stock reverse lights or dome light)

Wiring LED Front Light Bar, Rock Lights, Reverse Lights, and Footwell Lights

 

My bed and under hood light kits are designed for the electrical newbie to someone that just wants a complete kit. The install instructions are easy to follow with lots of pictures.

Links are in my Sig.