6. Lucky then told us to create a new charge wire that will run from the back of the alternator down to either the battery or the main 12V post on the starter. Since our battery is now in the truck, we decided to go to the starter post. The wire needs to be 10-gauge or larger to handle the increase in power the new alt will offer. We had some 8-gauge at the shop so we cut it to length, crimped on the proper-size ring terminals to each end, and covered it in some wire loom before installing one end at the alt.