Before the Battery

Evidence page

Portable power station for a travel trailer

Short answer: for a dry-camping weekend in a travel trailer, plan on roughly 400–1,200 Wh per night with the fridge on propane, and 1,000–2,000 Wh per night with a 12 V compressor fridge. A 1,000–2,000 Wh station covers that. Roof air conditioning does not fit, at any portable size.

Last updated 8 August 2026

What makes a travel trailer different

  • No engine, so no alternator of its own. Charging while driving depends on the tow vehicle’s 7-pin circuit, which is typically a trickle, not a charge.
  • Often no installed inverter, so the 120 V outlets are dead unless shore power or a portable station feeds them.
  • A propane absorption fridge draws almost nothing electrically. A 12 V compressor fridge is usually the largest single load of the trip.

A worked two-night example

  • 12 V compressor fridge: 500 Wh/day × 2 = 1,000 Wh.
  • Lights, pump, fans: 150 Wh/day × 2 = 300 Wh.
  • Devices and a CPAP without humidifier: 250 Wh/day × 2 = 500 Wh.
  • Total at the outlet: 1,800 Wh.
  • After an 85% delivery factor and a 15% reserve: about 2,490 Wh stored.

So the honest answer for that trip is a 2,000 Wh class station plus meaningful solar, or one shorter night, or the propane fridge. A single 1,000 Wh unit does not close it.

Where it stops working

Roof air conditioning, electric water heating and residential microwaves are shore-power or generator loads. If the plan requires them off-grid, the correct verdict is a different architecture — an installed lithium bank with a large inverter, or a generator — not a larger portable box.

Check your own trip

Run the RV weekend check. It starts with shore power availability and the battery you already own, and it abstains when air conditioning is requested without a provable supply. See also the general RV guide.