From 12/15: Just finished my dual battery set up. After reading a several random threads about it I decided to do it. First I moved the "charcoal" box and fuse box back about an inch or two toward the firewall utilizing other bolt holes and some creative mounting. Then I removed old battery tray, cut the original battery tie down and old fuse box mount ears off of the fender, and then beat the fender that was under the fuse box flatter. Then I added an eyebolt setup through the fender to replace the battery tie down ear, cut a 1x1x12 inch chunk out of the radiator plastic cover next to the battery location, replaced old tray with a marine dual battery tray, modded the old battery strap with some muffler hanger rubber strap to fit, added an 80 amp isolator just below the fuse box mounted to the fender, ran the 100 amp fused wires to split all my add-on (stereo, amps, inverter, lights, ect) accessories to one side and the rest of the truck to the other. All works great. Waiting for a dual battery switch that fits the dash panel to get here, then I will add a couple more wires to the system so it can self jumpstart from one to the other in emergency. Pretty stoked with the finished product. >1/17/16 edit< I did this at a cost of about $250, includes the cost of 1 new Advance Auto Gold Series battery. This is the identical battery as what I already had so I decided to go with the same option. Also, I am sure it may help that I have a GM CS-144 120 amp alternator installed in my truck vs the stock 70-80 amp unit. I have now added a dash switch that links the batteries for jump starting only. I too googled wiring options as there are many based on how and what your necessities for the system will be. I have had no issues to date, and I feel better about never having a dead battery failure.
