You can definitely wire them in directly to your existing 12v
circuit. I had those 70's florescent dome lights and the ballasts had gone bad in them. I chose to replace with bright white......kind of kept the original glow. Anyway, I just cut them to the length I needed, wired them in with the included adapter on one side, had to solder in 2 wires on the other side (only 1 adapter came with the strip) and then peeled and stuck them on the original light mounts. I did lay a full strip of clear Gorilla duct tape over them just for an extra secure. I did the lighting on the front and rear domes. Good luck with your project!