The running time of this propane generator model depends on the load of the volume of the tank you use for gas. At a load of 50% (approx. 2.5 kW), the generator will run for 8 hours on one 20-liter propane tank. At a maximum load of up to 5.5 kW, the generator will last about 4-5 hours on a full tank of propane. You can also use smaller or larger gas cylinders to extend or reduce the running time of the generator.