Community Forums

oldeguy · 06-26-2015, 08:02 AM

I purchased a used 5th wheel that has a house refrigerator. I want to be able to run the refrigerator off of house batteries while travelling. I know am going to need a DC to AC inverter, large amp/hr batteries, and someway to connect it to the refig. That is the question...how to make the connection EZ? I would like a seamless method like, it switches to battery power once disconnected from shore power. Has anyone done anything like this?

Skip426 · 06-26-2015, 09:17 AM

Finding the right inverter will be the first step , your looking for an auto change over inverter; one that has a connection to 120v so it sees the disconnect, and the best way to get that may be to replace your existing , converter/charger , with an all in one.
A lot will depend on ease of access to your 5ers existing wiring and space available.

bruceisla · 06-26-2015, 09:33 AM

Quote:

Originally Posted by oldeguy

I purchased a used 5th wheel that has a house refrigerator. I want to be able to run the refrigerator off of house batteries while travelling. I know am going to need a DC to AC inverter, large amp/hr batteries, and someway to connect it to the refig. That is the question...how to make the connection EZ? I would like a seamless method like, it switches to battery power once disconnected from shore power. Has anyone done anything like this?

First, you will need to determine the start and run amperage requirements. If you can see the reefer compressor, it is usually on a sticker. Otherwise, maybe some internet info for manufacturer/model. Once you know the amp requirements you can determine the size inverter that you will need. You will also need to know if your reefer can run on Modified Sine Wave (MSW) or if you will need a Pure Sine Wave (PSW) inverter. You will probably need a 1000 watt PSW.

The "seamless" part is not cheap. The easy way is to terminate the inverter output cord in a receptacle and move the reefer power cord from one source to another.

Triker56 · 06-26-2015, 11:02 AM

Why not put a small Honda generator in the 5th and run it every 3-4 hours for a while. A 2000W?
A residential will stay cold for a long time when shut off and door is not being open and closed a lot.

It will be cheaper then a big set of batteries & Inverter

paz · 06-26-2015, 01:35 PM

The motorhome we had previously and the 5th wheel we have now both had/have residential refrigerators. Both were in the 18 cu ft size range, and both ran fine on a 1000 watt inverter and two 6-volt golf cart batteries. The batteries in the fiver will last 6 hours when not plugged in and when the tow vehicle engine is not running.

The inverter in the MH had an integral transfer switch, which passes 120v thru to the fridge when on shore power, and the 5th wheel inverter has a separate transfer switch.

Most residential refrigerators need a PSW inverter.

oldeguy · 06-27-2015, 07:30 AM

Quote:

Originally Posted by paz

The motorhome we had previously and the 5th wheel we have now both had/have residential refrigerators. Both were in the 18 cu ft size range, and both ran fine on a 1000 watt inverter and two 6-volt golf cart batteries. The batteries in the fiver will last 6 hours when not plugged in and when the tow vehicle engine is not running.

The inverter in the MH had an integral transfer switch, which passes 120v thru to the fridge when on shore power, and the 5th wheel inverter has a separate transfer switch.

Most residential refrigerators need a PSW inverter.

You state that in the 5th wheel it had a separate transfer switch for shore power connection...can you explain that a bit more?

oldeguy · 06-27-2015, 07:59 AM

Here is my non-shore power thinking/direction at this point. Two golf cart batteries, a 1200-1800 watt sine wave invertor and a 1800 watt gas genset (Ryobi unit).

operational sequence...driving the truck will charge the batteries and the inverter will keep the refrig cold. at stops (lunch fill ups breaks), the batteries will do the job. Don't know if the truck supplies 12V power when ignition is off? need to test this.

non shore power over-nighters...fire up the Ryobi gen-set for 120 VAC power to 5'er. this will keep the batteries charged (I hope) because it has a 80 amp 120 VAC to 12 DC converter. With this being said...need to determine how to tie this gen-set into the 5'er.

Now the question is...do I do a manual switch over for the AC power to the refrig? or do I just continue to use the inverter off the batteries? Don't really like this option...but it would be seamless operation.

What do you think of my plan?