Originally Posted by mlts22
If needed, you can supplement the propane use with electric from the generator. The 2016 59G and the 59K have a load-shedding EMS in place to help with this.
Although the generator could be used to power the Truma in electrical (eco plus) mode it would be very inefficient. To supply the Truma's 1700 watt load the generator must consume about 0.42 gallons of gas per hour. Using Truma's fuel mode for the same output would consume 145 grams of propane per hour, or 0.08 gal/hr. So a bit more than 5 gallons of gas consumption for each gallon of propane.
The above assumes the Truma thermostat is continually ON. If the thermostat is cycling on/off 50% of the time to maintain temperature the numbers are even more dramatic, because synchronous generators such as the Onan are much less efficient at part load. Under these conditions the propane use drops exactly in half to 0.04 gal/hr. But the generator still consumes 0.31 gal/hr (0.20 idle + 0.42)/2. Now the gas to propane consumption ratio increases to 7.5 to 1.
So even with the Travato's limited 4.8 gallon net propane capacity it would take more than seven 5gal Jerry cans to provide the same heating, assuming the thermostat is cycling about 50% to maintain temperature. Or if you're willing to drain half the Promaster's vehicle tank for generating then you'd only need five extra Jerry cans of gas to match the onboard propane capacity.