Switching between dc and ac power for refrigerator

[John From Detroit]

How about using an AC/DC converter that has a 12v utility plug. Something like this one.
That way you only use the DC cord for the fridge. Leave the fridge end plugged to the fridge and plug the outer end into the converter/adapter when you want 120vac and into your onboard 12v outlet when you want battery power. No need to install a switch or modify a cord.

That is exactly what he has..; A Power brick type cord.

So he can do as he purposed in root post (Just switch between the two using a switch) or just use the RV's built in converter and keep the brick in case the primary fails.

I used that method with my Chest freezer in the Motor home. Just ran it on 12 volts. way easier than switching all the time.

 

[Henry J Fate]

Sorry for the delay; we've been trying to get ready for a little Thanksgiving trip with the Ranger, which, as of today, didn't work out.
The refrigerator is an Explorer Bear EX40B which was provided by the Aliner dealer where I purchased the trailer. There are two power cords - one for AC and one for DC. Both plug into the same connector on the refer. The DC cord then plugs directly into the DC outlet. The AC cord runs from the refer, then plugs into an AC adapter which then plugs into the AC outlet. This outlet is located at View attachment 176692the rear of the slide-in compartment that holds the refer. I practically have to crawl in the cavity in order to make the connection.

You have a 12 volt DC compressor fridge which is specified to draw max current of 4 amps.

The AC power cord provided is a converter from 120 AC to 12 Volt DC which plugs into an ordinary house 120 Volt receptacle and plugs into the same plug as the 12 volt DC power cord on the fridge.

You can wire a switch that switches the 12 Volt DC source from either of the power cords. I recommend using a switch rated for 10 amps and should be a 2 pole 2 position switch. You can include an OFF position if you desire.

The female power connector plug on the fridge should be a two wire socket for a positive and negative 12 Volt DC. Be sure to wire the switch correctly. A meter will help you identify and keep the integrity of the Positive and negative wires. The female connector on the fridge should provide a diagram indicating which is positive and which is negative.

I would also consider an inline fuse near the switch. The fuse should be about 5 Amps. Increase by 1 Amp as needed. You will probably be fine with a 5 Amp slow blow fuse. There will be some variances from the factory specified amp draw and will be more evident when the fridge runs from your 12 Volt batteries.

Consider soldering the connections to the switch. Properly soldered connections are more reliable than push on blade connectors.

The 12 Volt cigarette lighter plug can be unreliable and it is best to wire it directly to a 12 Volt source eliminating the cigg socket.

There has been some posts here of varying pins at the fridge socket. I have not looked at a schematic but I am fairly certain that the plug is an ordinary 12 Volt DC plug and all you will be changing with the switch is where the 12 Volts DC is coming from.

Good Luck with it all

 

[Gary RV_Wizard]

That is exactly what he has..; A Power brick type cord.

Right, but it is inconvenient to swap the entire cord to change power sources. Not sure why the OP even wants to do that swap, but my suggestion is to always use the 12v cord to the fridge and plug it to one of two 12v outlets, one from the RVs 12v supply and one from an independent 120v source via the suggested adapter. Not quite as elegant as a hard-wired switch, but very easy & cheap.

However, if the Aliner pop-up has a 12v outlet powered by both its battery and its converter/charger, then is no reason to ever swap power cords. Just use the 12v cord at all times and plug it to the Aliner's 12v outlet. When the Aliner is plugged to 120v external power, the fridge is effectively running on 120v even though the 12v fridge cord is in use. The only reason to use the fridge's 120v cord is if you want to plug it directly to some other outlet than the one on the RV itself, e.g.an extension cord to the campsite power pole.

 

[John From Detroit]

In his case unless the converter on the RV fails.. I'd just leave it connected to the RV's 12 volt system full time Keep the power brick in case the RV supply fails.

THe first one I had that's how I did it. Was easier than changing cords all the time.

Only issue with the 12 volt cord is those blasted accessory plugs don't work all that well (hard wire.. now that's an option. Cut the cord say 6" fromthe plug add a flat-2 polorized connector to the plug and to the rest of the cord splice another into the 12 volt feed in the bay All good and solid.

 

[Henry J Fate]

Something else to consider.....

If you dedicate the two factory power cords to the trailer, you will not have the ability to take the fridge out of the trailer and power it up at home. You could order a second set of cords or design your wiring to be able to remove the 120 volt cord and bring it with you so that you can plug it in at home.

As Gary and John have pointed out, you could wire it to the 12 volt trailer power only. This will free up the 120 volt cord for portability.

 

[rnelson1020]

This is what I will do; just power the unit with the 12V cord. Thanks for your input.

 

[rnelson1020]

In his case unless the converter on the RV fails.. I'd just leave it connected to the RV's 12 volt system full time Keep the power brick in case the RV supply fails.

THe first one I had that's how I did it. Was easier than changing cords all the time.

Only issue with the 12 volt cord is those blasted accessory plugs don't work all that well (hard wire.. now that's an option. Cut the cord say 6" fromthe plug add a flat-2 polorized connector to the plug and to the rest of the cord splice another into the 12 volt feed in the bay All good and solid.

Thanks, John; your suggestion certainly sounds like the simplest way to handle the issue. Thanks much for your input.

 

[rnelson1020]

Right, but it is inconvenient to swap the entire cord to change power sources. Not sure why the OP even wants to do that swap, but my suggestion is to always use the 12v cord to the fridge and plug it to one of two 12v outlets, one from the RVs 12v supply and one from an independent 120v source via the suggested adapter. Not quite as elegant as a hard-wired switch, but very easy & cheap.

However, if the Aliner pop-up has a 12v outlet powered by both its battery and its converter/charger, then is no reason to ever swap power cords. Just use the 12v cord at all times and plug it to the Aliner's 12v outlet. When the Aliner is plugged to 120v external power, the fridge is effectively running on 120v even though the 12v fridge cord is in use. The only reason to use the fridge's 120v cord is if you want to plug it directly to some other outlet than the one on the RV itself, e.g.an extension cord to the campsite power pole.

Thanks, Gary! I like your thinking and do believe my problem is solved - just use the 12V cord and forget about the 110 cord.

 

[John From Detroit]

Thanks, John; your suggestion certainly sounds like the simplest way to handle the issue. Thanks much for your input.

Do not lose the 120 volt cord/brick however.... I now use mine in my apartment... used it in the house from time to time as well.