The 12volt 50 watt bulb will eat up the vex battery pretty quick. Although you may get 2-3 hrs of usable light out of it.
Many of us are now using LED lighting in our portables attached to a support bar with the wires attached outside or through the bar with a small hole drilles near the light location with a vex battery for power. You have a pretty good selection at most truck stops. Depending on how many you use you can get 30-60+hours of usuable light using a vex battery.
Down side is that it will be more costly to assemble than the 12v 50 watt bulb setup. Generally in the 20-50 dollar range depending on how much light you need.
Although the long term cost is signicantly less than using a propane lantern and you don’t need to figure out what to do with all the empties.
I’m pretty sure they make an LED bulb that would screw into that setup. However I don’t know the cost of such a setup.