wanderso Posted July 18, 2011 Share Posted July 18, 2011 Our 1991 Warrior has the Norcold fridge that is 2-way (LP or 120v, no 12v). Since in most cases I am going to parks that have electrical, I've wondered about installing an inverter and running the fridge off of that when I am driving enroute. The added feature in my mind is that not needing to run LP when on the highway is a nice safety benefit. Has anyone tried this? Yes I could go to a 3-way fridge, but an inverter seems to be a less expensive option that also gives me additional uses provided that it does not put too much stress on the coach, truck battery and alternator. Any suggestions to find out the 'starting amps' requirement of the fridge's 120v heater? Quote Link to comment Share on other sites More sharing options...
WME Posted July 18, 2011 Share Posted July 18, 2011 Works fine, just remember to cool the inverter. Remember it will be drawing 3-5 amps from the battery so don't leave the engine off for to long. Quote Link to comment Share on other sites More sharing options...
waiter Posted July 18, 2011 Share Posted July 18, 2011 Powering the Refrig through an inverter should work, the Logistical complexity issues would be about the same as propane (i.e. remember to plug it into the inverter, remember to turn the inverter ON and OFF). You could try this fairly easily, Pick up an inexpensive 300 or 400 watt inverter and plug in the frig. The frig should draw 130 - 150 watts, this is about 10 amps at 12 volts, about the same as leaving your headlights turned on. NOTE - Besides running the Refrig, use one of these low power inverters to power a computer, TV, cell phone charger, other low power items. The issues will be 1) Don't forget to turn the inverter ON/OFF or you'll run down and possibly kill your coach battery. The Inverter should kick off when battery voltage drops below about 10 volts. If you were only going to use this when traveling, you could wire your inverter through an isolator solenoid so the inverter only gets power when the truck is running. You could also run another relay to supply Inverter power when plugged into shore power. 2) How to switch Refrig power from inverter to 110 outlet. You could wire the Refrig power cord through a Wall switch or a Relay (i.e. like a regular household wall switch) . Label the switch "Inverter" and "Shore". OR, you could wire a relay to switch this automatically when plugged into shore power. Heres a diagram that should work to automatically select power to the inverter. Just leave the Refrig plugged into the inverter, 12 volt power to the inverter is switched automatically depending if your plugged into shore power or the truck is running. note a 110 volt relay and a 12 volt relay. These need to be at least 30 amps. The 12 volt relay can be a standard SPDT automotive cube relay. 110 volt relays may come in DPDT, to raise the current capability, wire the poles together. i.e. wire the Cs, NOs, and NCs to each other. JOhn Mc 88 DOlphin 4 Auto Quote Link to comment Share on other sites More sharing options...
Maineah Posted July 18, 2011 Share Posted July 18, 2011 I just checked a fridge over the weekend it drew 156 watts at 120 volts or 13 amps @12 volts. I'll tell you they use very little gas the only thing that would be a problem is filling your MH up you really should turn off the gas when refueling. I have been all over with mine running on gas with no problems they have a thermo couple so if the flame goes out the gas shuts down. An inverter surely would work but it seems like a bit of over kill. As waiter suggested it is best to kill power to the inverter even if nothing is running because they do draw power (idling current) as long as they are powered. The inrush current to an inverter is pretty high due to capacitor charging so be sure to over size your wire by one gauge if it's going to be turned on and off. Quote Link to comment Share on other sites More sharing options...
waiter Posted July 19, 2011 Share Posted July 19, 2011 I run my frig off propane- it'll run for weeks (maybe months) on a tank of propane. John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
old goat Posted July 22, 2011 Share Posted July 22, 2011 Our 1991 Warrior has the Norcold fridge that is 2-way (LP or 120v, no 12v). Since in most cases I am going to parks that have electrical, I've wondered about installing an inverter and running the fridge off of that when I am driving enroute. The added feature in my mind is that not needing to run LP when on the highway is a nice safety benefit. Has anyone tried this? Yes I could go to a 3-way fridge, but an inverter seems to be a less expensive option that also gives me additional uses provided that it does not put too much stress on the coach, truck battery and alternator. Any suggestions to find out the 'starting amps' requirement of the fridge's 120v heater? I use a 12v relay to turn the 120v ac off and on. It is connected to the hot terminal on the spark coil. I ran a cord, pluged into the inverter to the ref compartment. Then cut the hot side in two and attached the two ends to the relay. Works great as long as you remember to turn the inverter off. I left it on for two days and noticed the battery way down a bit. Quote Link to comment Share on other sites More sharing options...
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