toyohome Posted November 4, 2014 Share Posted November 4, 2014 I have a Dometic RM2410 refrigerator which is 110v and propane only. I would like to operate it off my house battery with a separate inverter to up the 12V to 110V. I have a separate 750 watt inverter for that sole purpose. For all you electrical wizards: The RM2410 is listed at 120v and 1.3A. Is there any reason why this would not work during road travel and boondocking? Quote Link to comment Share on other sites More sharing options...
Donnie Posted November 4, 2014 Share Posted November 4, 2014 Hello, I am not familiar with the model that you have, but I think that since it has the ability to use propane......it does NOT have a compressor, but uses heat to move the coolant thru the system,,a more detailed explanation of how this system operates is not needed for this discussion.. I think that since the mfg. did not offer a 12 DC option.......they deemed the unit too large to use battery power to heat the gas.. 12 volt on motorhome units is the least desired system to use....Unless there is something wrong with your propane system, or you are not comfortable with PROPANE???........I would never use a 12 electric heater in this situation... Don't get me wrong, I use a 12 volt refrig in my small Toyota, but it is a compressor model My larger truck, a 12,000 pound Travco has propane & a 110 option.....I NEVER use the electric heater in it...ALWAYS PROPANE...hth Maris will chime in when he catches this post & add much more than I have added....these are just my thoughts.......Donnie Quote Link to comment Share on other sites More sharing options...
zero Posted November 4, 2014 Share Posted November 4, 2014 I have a Dometic RM2410 refrigerator which is 110v and propane only. I would like to operate it off my house battery with a separate inverter to up the 12V to 110V. I have a separate 750 watt inverter for that sole purpose. For all you electrical wizards: The RM2410 is listed at 120v and 1.3A. Is there any reason why this would not work during road travel and boondocking? Yes, it will work but it's going to draw 15 amps when you use an inverter and 12 volt battery. A 12 volt refrigerator with a compressor instead of a resistance coil like your's has would use less then half that amp draw and come on less often. Much more efficient.. If you can live with a 15 amp draw, you'll do OK. An AC refrigerator with compressor and hooked to an inverter would also be more efficient, but then you'd lack the propane option. Quote Link to comment Share on other sites More sharing options...
toyohome Posted November 5, 2014 Author Share Posted November 5, 2014 Thank you! That's an excellent point on absorption vs. compressor. I never thought of that. Out of curiosity, how did you arrive at that 15A draw figure? Do you have a formula? I'm just trying to find a solution to my propane burner going out when I'm on the road. Any suggestions on that? Quote Link to comment Share on other sites More sharing options...
linda s Posted November 5, 2014 Share Posted November 5, 2014 I don't really worry about my fridge blowing out. They are very well insulated and nothing is going to go bad in a few hours of driving especially when your not opening and closing the door. Mine does blow out occasionally but I always check it when I stop and relight if necessary. Linda S Quote Link to comment Share on other sites More sharing options...
zero Posted November 5, 2014 Share Posted November 5, 2014 Thank you! That's an excellent point on absorption vs. compressor. I never thought of that. Out of curiosity, how did you arrive at that 15A draw figure? Do you have a formula? I'm just trying to find a solution to my propane burner going out when I'm on the road. Any suggestions on that? Formula is Ohm's Law from 1827. Your refrigerator has a heater coil with 92 ohms resistance. Designed to run at 120 volts which comes to 156.5 watts and 1.3 amps. 156.5 watts @ 12 volts is 13 amps but there is approx 15% loss using an inverter and battery. That comes to 14.9 amps @ 12 volts using an inverter when the engine is not running and charging your house battery. When the engine is running and system voltage comes up to 14 volts, amp draw will be 12.7 amps (approx). Quote Link to comment Share on other sites More sharing options...
Maineah Posted November 5, 2014 Share Posted November 5, 2014 Yeah that's pretty close I did check mine once with a watt meter and it drew 175 watts. The electric heater most likely will not cycle in warm weather so the 15 amps is long term you would be far better off with propane a 20 cylinder should last you pretty much all season mine does and I use the stove for cooking also. My fridge heater has never blown out on any of my campers the fire box is pretty well protected. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted November 8, 2014 Share Posted November 8, 2014 the 12vdc option should work ok while driving - the engine alternator should handle the load, assuming it is not running at a high load trying to charge the house battery. However, while parked, the 12vdc option is questionable at best. Using an invertor to create 120vac source - is a waste of energy (hint - invertors get hot - that is wasted energy) will hammer your battery bank - you will need a lot of batteries - which means a lot of weight & a lot of space - space that has to be vented outside the cabin. Of course those batteries will have to be recharged which will require a lot of energy. I suggest you consider just using the propane energy source. You could consider adding a 12vdc heating element to your frig - I have had a 2410 apart (when I replaced one) and noticed that there were 2 mounting spots for eating elements - 1 for 120vac & 1 was empty. I gather the 12vdc units do not use a thermostat - they just run while plugged in & they will kill batteries pretty fast. Quote Link to comment Share on other sites More sharing options...
zero Posted November 9, 2014 Share Posted November 9, 2014 Using an invertor to create 120vac source - is a waste of energy (hint - invertors get hot - that is wasted energy Granted using any electric power source to run a non-compressor refrigerator is very inefficient. That being said, a properly matched inverter barely gets warm. I've run a small AC compressor refrigerator in an RV for weeks with a 1500 watt inverter and it does not even get warm to the touch. If fact it has a thermally controlled cooling fan that has never come on. General rule of thumb is a 8-10% power loss when using an inverter with big difference with voltages between the input and output;. Less loss as the voltages get closer. like when feeding 48 volts DC to make 120 volts AC. In regard to thermostats in absorption refrigerators - I just fixed the electric thermostat in a Dometic. It had two thermostats. Has one for propane and one for electric. I can't say if they are all like that but I assume they are. Quote Link to comment Share on other sites More sharing options...
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