OK, this counts as fabrication because... " bracket". 
Have you ever over thought something? Something that didn't need thinking about to begin with? Ya, us too...
So we had to jump start the ChevyBaker one day, a while ago, and it bugged us. It really really bothered us. So we did the correct thing and bought a trickle charger. It is small, inexpensive, and we were able to route the wiring to repurpose the fuel door since we previously modified the fuel fill. 
We can simply open the fuel door, pull out the charger and plug it in to an extension cord.
But it did not stop there. We went that next step and added a remote disconnect as a sort of "security measure". Now when we exit the vehicle we can remotely disconnect the battery on the negative side.
Additionally, the disconnect has a voltage display.
Side story:
We took the ChevyBaker to a tire shop and checked in. When the technician approached the car we thought it would be in our best interest to go out and see if he needed anything. He put in the key, turned it, and nothing happened. We thought the battery was dead but then noticing the dome light was not on (because the door was open) we asked, "Did you push the key fob?" He did thinking the fob meant the doors had automatic locks. He not only pushed the unlock button (which would have turned the battery disconnet off (double negative?) but then pushed the lock button thus disconnecting the battery. We have since put the spare keys on something easy to separate. Now we can give the ignition and truck key only.