Consider this when adding additional wires from the battery to improve
the performance of lights or whatever; the battery is not the source of
current while the engine is running. In fact, it only supplies current
when the alternator can not keep up with the load. A correct wiring
upgrade would be to install additional wire capacity from the
alternator. The factory wiring is terribly inadequate for the job at
hand. To fully utilize the capacity of the 90 amp alternator, you need a
4 gauge wire. That size is a bit balky and hard to terminate on the
alternator. My fix is to install#6 or #8 from the alternator to the feed
on the fuse box. This makes a noticeable difference in the performance
of all the accessories.  This new feed can then be used with the relay
upgrade for the lights or what ever you need it for. Also helps to
supply adequate capacity for charging an auxiliary battery.

Dennis