Inverter to run refrigerator while on the road

David D. · June 18

We have a 2017 Cougar fifth wheel with a residential 120 v refrigerator installed. We want to keep the food cold while traveling. Looked into adding solar + AGM batteries and buying a 12 v refrigerator. However, that was going to be $4000 + refrigerator cost. Alternatively wondered about getting an inverter just to keep the refrigerator running while on the road and keeping my 120V fridge.

Would this drain my batteries too fast? Was looking at getting a 1000 W inverter and we have two marine lead/acid batteries in parallel right now. Would the trickle charge from the truck keep the batteries adequately charged when used with the inverter? I estimate my wattage use for the fridge to be about 300-400 W max. But I may be wrong! Any suggestions? Would welcome thoughts about 12 V fridge vs 120 v and inverter vs solar. Thanks.

Kirk W · June 18

More is needed to be sure exactly what will happen. A 1000 watt inverter can supply 8.2a of 120V power so it is probably more than you would need. For each amp of power it is supplying the inverter will need 10 amps from the batteries. Of course the maximum it draws depends on what your refrigerator uses when the compressor is operating and that is probably no more than 6a-120V or 60a-12V from your batteries. When the compressor is not running the inverter requirements will be nearly 0a. To get more accurate we need to know exactly what batteries you have as there is a wide range of battery sizes in terms of ampere hours. (1a for 1 hour is 1 amp-hour) You might need to run a larger wire for the 12V supply from your tow vehicle as that wire size can limit the ability to recharge the trailer batteries.

GlennWest · June 18

I have a Victron Phoniex 48/ 1200 watt unit on my fridge. It stays on always. Uses very little power to operate. I can't answer draw since I have a large 48v battery bank and large solar system.

Randyretired · June 19

We have a residential refrigerator in our 5er. When it is running it uses around 200 watts. Ours is 18cuft energy star. Of course size and brand can make a difference but likely your truck will be able to keep up as the refrigerator only occasionally runs especially if it isn't opened. We have solar and rarely go to campgrounds. 12v refrigerators are to expensive. A small inverter will be close to 90% efficient. For the difference in price you could add a solar panel to assist the truck and still be money ahead.

GlennWest · June 19

Should add mine is a 26 cf fridge but a very new Samsung energy star unit. My Victron app doesn't should how many watts just a graft. It is very little though. I could have got by with a smaller inverter.

Randyretired · June 19

I thought a little more about this. Our refrigerator uses 1kwh a day. That is 41wh an hour. Your truck should easily handle that even if your refrigerator used twice as much.

Edited June 19 by Randyretired

D&J · June 19

We are running a 2000W pure sine wave inverter to run our 10.1 CF refrigerator and 3.5 CF chest freezer when running down the road and our Ford truck keeps the batteries up. The frig uses 57 watts when running and the freezer a little more. Last fall my AGM batteries started getting weak so I converted to two 100 AH lithium batteries, 20 amp DC to DC charger and a new converter to charge the lithium batteries. Now when running down the road with the DC charger the truck keeps the batteries fully charged. We also use the inverter to run the entertainment center, frig and freezer when dry camping.

Denny

David D. · June 19

Thanks to all who responded. Very helpful!

David

bruce t · June 20

Look at something like the Bluetti battery units. Charge from the engine while travelling plus run the fridge. Lots of these multi purpose power units now on the market and they are so simple. Portable and can be used away from the RV.