Running Multiple Off-Road Lights off the same relay

I doubt it will be a problem. They size the alternator to be able to charge the battery, run the engine, stereo (stock), wipers, lights, etc and still be able to charge the trailer battery if you're towing. Take away the towing and the wipers (who runs all those lights in the rain, anyway?) and I doubt you will have a problem. You could have the system tested at a shop to see if you have any reserve left or if you are officially pulling more amps than the alternator will provide.

Most factory batteries are rated to provide 100 minutes or more of reserve power without the alternator charging. I believe that's with a 25amp draw. So you could have a 25 amps deficit for over an hour and still not have a problem. My buddy had 4 130W lights on his Jeep with 120A alternator and big ass stereo. We used to go to the sand dunes and run around with all that on for a few hours. Never had any problems.

 

Right, the lights are pulling 43.3 amps 4x130 (watts)=520 (watts) divided by 12 (volts) = 43.3 amps I should be ok, I'm going to look up the amp draw of my headlights on bright, add that in as well. The stereo is not much (stock) and then the engine.