frig on inverter during travel

[gobike]

I would like to run my 2 way frig off a inverter while traveling. Is this possible, where to find accurate info on proper install.
Thanks

[avanti]

Originally Posted by gobike

I would like to run my 2 way frig off a inverter while traveling. Is this possible, where to find accurate info on proper install.
Thanks

What do you mean by "2-way"? Propane/electric? 120VAC/12VDC?

In any event, if it is 120VAC, you certainly COULD run it through an inverter, but if it is a compressor fridge with 12VDC input, you are better off using that.

[gobike]

it is a propane/120v non-compressor

[Bud]

Simple gobike, just plug the refrigerator ac cord into the inverter. Been doing it for years, but I had an inverter already. What do you have?

[Davydd]

I thought absorption RV refrigerators were 3-way 120v/12v/Propane. Underway you could 12v directly off your batteries which simultaneously receive charge from your engine alternator(s) or solar, propane when stopped without shore power or 120v when plugged into shore power. My former Pleasure-way and Great West Van was this way. My current compressor refrigerator is supposedly 2-way 120v or 12v but it is setup for 12v at all times shore power, boondocking or underway.

[eric1514]

The absorption fridge in my C is 120 or propane, no 12v heat and it switches to propane when not plugged in. From the factory, it's meant to operate on gas when on the road which is what I do.

[gobike]

no inverter yet, need to know all the particulars, watts, amps, wire guages, etc. etc. and will it even operate while driving, will the alt. charge the battery, on and on.

[GeorgeRa]

In your size calculation make sure to take 80% inverter efficiency, and because AC fridge is resistive load MSW (modified sine wave) should be OK. If you plan to use this inverter for other electronic equipment PSW (pure sine wave) would be more appropriate.
My last 6 CuFt 3 way fridge was pulling 150W.

[Rlum]

Originally Posted by gobike

no inverter yet, need to know all the particulars, watts, amps, wire guages, etc. etc. and will it even operate while driving, will the alt. charge the battery, on and on.

My 2016 PW Lexor is set up that way. It is a three way but when on road, we use our inverter to run it. The alternator will keep the batteries fully topped off. No problem. This is the way it is set up.

[GeorgeRa]

Many inverter options, this one is one of two inverters I have in my van for low power. Very robust, practically sealed (no fan) and very efficient. https://invertersrus.com/product/mor...r-si-300-115v/

[avanti]

My 2005 Airstream Interstate was 120VAC/Propane only, so they do exist. We ran it on the inverter often. Works fine as long as the inverter is large enough.

[Nic7320]

You'll need at least 300 watts for the 120 VAC mode. And warning -- that will suck your battery down in a hurry if you forget to switch modes.

So get an inverter with a programmable low voltage shutdown if you can, in case you forget to switch it off. You can add them if you have an inverter that doesn't have it (e.g. a Victron Battery Disconnect). That will save your battery, but at the expense of your contents in your refrigerator. A min-max thermometer in the fridge is a good thing to have.

My DM2652 3-way fridge is spec'd at 440 watts (based on BTU equivalent, not actual AC power demand), but I've measured it at 300 Watts running on a 70 degree day.

And when i left it plugged in for a month, it doubled my house electric bill (in dollars, not kWh).

[nicaland]

This can certainly be done but just make sure that you alternator is big enough to handle the additional load without running even close to it's rated amp output, and I believe that this will usually be the case. For example I have a 136 amp alternator and with normal chassis loads including the ac running and a small battery charger also running off my 2000W inverter I have had no problems running my Dometic RM2310 while going down the road. It has a 160 watt/120V heating element, so if you figure 85% inverter efficiency and alternator voltage output at 13.8 volts, it's pulling around 13.3 amps additional load from my alternator. Just don't forget to switch back to soon after shutting down your engine!

[Nic7320]

This might also help:

A 300 watt load on an 80% efficient inverter requires 375 watts from the battery. If there's say, 8 feet of wire from the battery to the inverter (16 feet round trip) that requires 8 AWG to get 4% voltage drop, and 6 AWG for 2.6% voltage loss. Both of those are acceptable and only get better if you're going a shorter distance. You'll need a good quality fuse holder and a fuse located close to the battery, that also adds some voltage drop.

But if you locate the inverter next to the battery, an extension cord of almost any size can handle 300 watts, and you can go down a size on the DC feed.

[gerrym51]

just remember a propane fridge-is still an absortption fridge no matter what power source your using

your heating a boiler to heat gas to go thru coils which recondense and do the entire cycle again.

the boiler draws a LOT of battery power when not on propane It is not the same as an efficient compressor fridge.

I'd just stick with the propane.

[gobike]

yes I intend to do so. It is while traveling only that I wish to use a inverter to power the frig.

[gerrym51]

Originally Posted by gobike

yes I intend to do so. It is while traveling only that I wish to use a inverter to power the frig.

so while driving how are the batteries being charged?

[gobike]

apparently it can be done with the alternator, but this is what I need to find out for certain.

[gerrym51]

Originally Posted by gobike

apparently it can be done with the alternator, but this is what I need to find out for certain.

it is done by your alternator. what i meant is how many amps are you getting out of your alternator. i suspect you will run down your house battery doing this

[markopolo]

OP has a '97 RT I think. My similar vintage Dometic RM2410 heating elements are listed as being:

DC Heating Element: 125W
AC Heating Element: 160W

It would use up to 11A or so in DC mode and 14A or so on AC mode through an inverter.

AC 160W divided by 13.0VDC minimum expected alternator voltage = 12.3A
12.3A divided by 85% to allow for efficiency losses = 14.47A

( basically what nicaland already posted above )

No problem for the alternator as maybe only 4A to 5A more than driving around with the fridge on DC mode with this type of older and small Dometic fridge.