CHAPTER Power sources 16 The power we need to run our lights can come from a number of sources: a small battery pack, a small 5500 W generator, via the power utility (a transformer connected to the power lines), a large diesel-powered portable generator, or a 480 V step-down transformer. In each case, the lighting tech- nician needs to know how the system operates, its potential, its limits, and problems to watch out for. We'll start small and work our way up. BATTERIES AND INVERTERS In situations in which no other power source is practical--such as when shooting in a moving car, a boat, a remote cave, or on the run--a rechargeable battery pack can provide enough DC power