I call this the: fuck you EPA mod.
Remove the secondary battery solenoid.
Remove the bullshit secondary battery.
Secure the ground wire using a battery box screw.
Connect the three hot wires (two from the solenoid, one from the secondary battery) using a nut from the solenoid and a bolt from the battery box. Then insulate with electrical tape.
Optional: drink a whiskey and cuss at commies and hippies and shitty engineers who fuck everything up.
Total time is about 90 minutes, including remove and install of fender, not including optional whiskey and cussing steps.
Now your truck won't die when the bullshit motorcycle battery dies and cuts off the power supply to all the vehicles electronics.