Thats not correct. You battery still has to power the load. The relay will just act as a switch. That way that extra load is not going through your headlight switch, which will more than likely burn it up. Your headlight switch will activate the relay which will switch on the light bar.The relay or relays, will take most of the load off of your charging system as a relay is made to use a small amount of current to control a larger amount. The battery only has to work hard enough to energize a coil within the relay which is easier then the battery having to power on the lights directly. LEDs will pull a considerably smaller amount of current then a halogen and outlast it 10 to 1.