When I had 4ga. run to the trunk the installer never ran it from the alternator to the battery. I was considering running 1ga. between them in case I decide to upgrade my alternator to something beyond 100Amps. Should the line from the alternator to the battery be fused? Also, seems obvious but I'm asking to be safe... I'm assuming that when I add the new wire that it can be run in addition to the currently installed wire. Considering the mess of factory installed wiring I don't want to replace the original if I don't have to. Thanks -RC