I'm thinking about mounting some off-road lights on my Samurai. I have the factory charging system. What  can I get away with as far as lights go without sucking down my battery? I was just thinking about a couple of 100 watt lights. Anybody have any experience with this? Thanks in advance.

I  don't know much about the sammies
but a couple of 100 watters will be too much to begin with.
You'll never out drive them anyways.
a nice set of good 55watt driving lights and a set of Fog (wide beam) will work good.
I use the Pro Comps 55s spot and fog
Fog (wide beams) work good for crawling and the spots for off-Road driving.
But thats me