by GTS225 » Fri Oct 28, 2022 9:32 am
Phil's right. You need to do some math, with finding the wattage rating of the fridge first. If the specifications sticker doesn't list it, but does offer volts and amps, watts is the product of volts multiplied by amps. You would then need a 12 volt source that could supply at least that many watts, in order to install an inverter rated that same way.
ARBITRARY example------120vac times 8 amps = 960 watts. You'll need not less than a 1000 watt inverter, with battery that can supply 1000 watts of 12vdc power. That's 83.3 amps draw on that battery. (Only while the compressor of the fridge is running. Once it's down to temp, it's just a circulating fan that draws power.)
Harbor Freight sells low-cost inverters that would do the job, but a decent battery can get spendy. (Close to $200.) I would recommend an AGM type RV battery.
How long is your trips, that you'd have to run the fridge independently for? A 100 amp-hour battery will tolerate 100 amps for 1 hour, as a baseline comparison.
Something else you could plan for is solar battery recharging. A 100 watt (or larger) panel mounted on the roof, wired to a suitable charge controller will recharge that battery during the day, or at least extend the times between having to recharge it. You could build a small cabinet right under the fridge to house the battery, inverter, and charge controller for a stand-alone system.
Your other choice is running a LARGE, fused wire from your tow vehicle battery, out to your rear bumper, to supply power for the inverter for the fridge. Large as in about 6 gauge, (rated at 65 amps). Too big to go through that 7-pin connector.
Another option might be to mount the inverter under the hood, and run the 120vac wires out to the rear bumpr so you can connect it to the trailer. Simple, cheap, and dirty?.....yes. (Not recommended due to dangers of connection and wire abrasion.) You would also run the risk of forgetting to unplug it at the campsite, drain your tow vehicle battery, and find yourself temporarily stranded.
No matter what, you're going to have to drop a couple hundred on an inverter large enough for the fridge, unless you can find a deal on Marketplace or at a local pawn shop.
Let's find out the demands of the fridge, first.
Roger