If you're using multiple sets of lights you probably should upgrade your alternator.For off-road lights I usually run thru a relay.The relay operating voltage can be lower amperage thru the switch(fused) & then the power to the lights should be larger guage wire(fused).
I usually pull power for the control ckt(switch & relay) from the fuse block & then pull power to the lights direct from the battery(with an inline fuse under the hood). Hope that helps.