If you haven't tried wheeling at night you are missing out on a whole new experience.  Old trails feel completely different at night not to mention the temperatures are much more bearable for us desert dwellers. Here's a run down on buggy lighting.

Headlights

In my experience nearly any auxiliary driving light with at least a 100 watt bulb will work fine for headlights on your rock buggy.  Most lights come with 55 watt bulbs as they are designed to be auxiliary lights on street driven cars.  Sometimes you can swap out the bulbs for higher wattage units but keep in mind the higher wattage bulbs will generate a lot more heat and the light housing may not be able to handle the temperatures. 

I used to run a pair of Hella 500 lights which come stock with 55 watt bulbs.  I found these insufficient for driving fast at night until I swapped the bulbs out for 100 watt units.  A couple years back I switched to the light pictured above, a Eurolite TF2000.  This light came with 100 watt bulbs from the factory and they put out a lot of light.  I also felt the beam pattern was broader than the Hella 500's which made driving around on twisty roads much easier. These lights are getting harder to find now, the last set I bought was from a liquidator on E-bay.

Rock Lights

The goal of rock lights is to provide enough illumination around the tires so you can see the obstacles as if it were daylight. The rock lights need to be mounted so they are up an out of harms way but at the same time they put the light where you need it. There are several types of lights that can be used for rock lights, the most common being fluorescent, incandescent and LED's.  Fluorescent lights are very delicate so I have never tried using them in a rock crawling environment.

Incandescent lights were used in all the pictures above.  They throw off a lot of light, come in all shapes and sizes and best of all are fairly inexpensive.  In my experience 2-3 of these lights should provide plenty of light for a typical rock buggy.  I usually like to have one on each side of the rig, behind the driver and firing forward towards the front tire and one centered up by the rear bumper pointing straight down.

The downsides to incandescent lights is their power consumption, delicate bulbs and heat generation.  Most of these lights draw somewhere from 35-50 watts of power each so you can easily exceed the output of your alternator if you run too many lights at once.  You must also be careful about leaving the lights on with the vehicle off as they can quickly drag down a battery.  I have found the bulbs in these to be very sensitive to hard hits to the chassis and the glass on the housing does not hold up well if you attempt a water crossing usually cracking as soon as the hot glass hits the water. Ironically it is usually cheaper to just buy a new set of lights than a new bulb, especially if you get the lights at a sale price (Harbor Freight drops them to $6 from time to time).

The new kid on the block is the LED.  These have actually been around for a long time but it wasn't till the last few years that they started coming in various form factors useable in an automotive environment. LED's have a number of advantages over incandescent lights with the biggest being a very low current draw and near 0 heat generation. The above picture shows a 6 LED module from www.superbrightleds.com, this unit is marketed as an accent module.  This module draws so little current you could hook 10 of them up and still draw less power than a single 55watt incandescent driving light. Many of these modules come with their electronics potted so they are nearly impervious to water or can easily be sealed up.  Also, since they don't have a filament they are virtually indestructible when it comes to shock and vibration with no heat generated they will not crack when immersed in water.

The above mentioned site also carries single LED accent modules like the ones shown above.

There are also LED units in a driving light form factor available like these 12 LED units I found on E-bay.  This style throws off more light than the accent types but they also cost more.

The downsides to LED's is they throw off a much softer light than an incandescent bulb.  In the picture above there is an LED rock light illuminating the area behind the front tire and an incandescent rock light lighting up the area behind the buggy.  For this reason you will find you have to get the LED style lights closer to your target area for best illumination.

Here is one way I found to accomplish the task of getting the LED module close t the area of illumination while still protecting it from direct contact with the rocks.  The module will be captured by a small keeper on top of the boatsides and the LED's poke thru the boatsides via a set of drilled holes. 

All LED's are not created equal.  You would think more LED's would equal more light but I have found this not to be the case. All of the above LED's are available from www.superbrightleds.com and after seeing them all in action I think the Luxart single bulb modules are the brightest (and also the most expensive).  The 6 LED  ALM-C-X6 modules shown in the middle are a close second and the 6 LED MCM modules coming in at a distant 3rd.