LP Truma Usage for Travato

[tbirdman]

How efficient is the Truma for heating the Travato? I'm concerned the LP capacity may to small to really boondock with the cold weather i.e. 40-50 degrees at night

[thefitrv]

When I met their reps at Winnebago GNR, they claimed greater than 90% efficiency. Personally, we're planning to camp at quite a bit colder than 50 degrees, and we're not concerned at all.
If propane capacity is a concern, opt for the gas Travato 59K, which will come with a gas generator, and a 12v only fridge.

[tbirdman]

I should have said 59K. I wasn't thinking about the fridge in the 59G which could use propane.

Question is what does 90% efficiency translate into?

[thefitrv]

I don't think you'll see any real world Truma/Travato numbers until it gets colder.

[tbirdman]

I did some searching and from European forums I've been able to tell, you should be able to get about a weeks use in Alpine conditions. So in warmer 40-60 degree temps, you should be able to go a lot longer on LP refills.

[thefitrv]

That sounds reasonable to me. The few times we've run our Truma for heat, we haven't really noticed any dramatic propane usage. In fact, we haven't refilled our propane yet since taking delivery in early July.

[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.

If boondocking and it is cold, you have two choices with a hitch mounted cargo rack: Buy a few gas cans (and mounting brackets) to extend the onboard Onan's runtime, or buy a mounting bracket, two 20 pound propane cylinders, and tee those in using an Extend-A-Stay system. The nice thing about the Truma system is having that choice, although I'd rather take some gas cans as opposed to additional propane if at all possible.

[markopolo]

Nice write-up on RV Business today: Winnebago’s Travato Now Features Truma Combi | RV Business

[rockymtnb]

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.