How much solar do I need for a travel trailer?

Answered by RV Parts Giant · Upland, CA · October 11, 2026

Short answer: For a typical travel trailer with a propane fridge, a TV in the evening and a morning coffee or microwave run, our calculator lands at about 474Wh a day: 150W of solar and a 100Ah LiFePO4 battery for two days off-grid. Switching to a 12V compressor fridge is the change that moves it most, to 250W and 150Ah.

The travel-trailer preset in our calculator starts from what most trailer owners actually run when they are off hook-ups, then sizes the system around it.

What the preset assumes

Load	Amp-hours a day (12V)
Lights, water pump, phone charging, vent fans	18
Propane (absorption) fridge, controls only	3
TV or entertainment in the evening	8
Morning coffee maker or microwave, through an inverter	8
Total	37Ah, about 474Wh

It also assumes two days between recharges, about five peak sun hours, and that you park and stay put rather than charging from the tow vehicle. The math uses a 12V bank, 85% usable LiFePO4 capacity, 75% real-world solar harvest and 92% inverter efficiency for mains loads.

The result

Solar: 150W. One 200W panel covers it with room to spare.
Battery: 100Ah of LiFePO4. Two days at 37Ah is 74Ah, and 85% of 100Ah covers that.
Charge controller: SmartSolar MPPT 75/15 or 100/20.
Inverter: a MultiPlus 2000VA, because the coffee maker or microwave peaks around 1,500W. Leave that load out and the calculator drops the inverter entirely.

What changes the answer

Run the same preset with one change at a time and you get:

Change	Daily use	Solar	Battery
Preset as above	474Wh	150W	100Ah
12V compressor fridge instead of propane	755Wh	250W	150Ah
Furnace or diesel heater running at night	602Wh	200W	150Ah
Three days off-grid instead of two	474Wh	150W	150Ah
Cloudy or winter sun (about 3 peak hours)	474Wh	250W	100Ah

Two patterns are worth knowing. More days off-grid grows the battery, not the panels, because the array only has to replace one day at a time. Less sun grows the panels, not the battery. The fridge is the one choice that grows both, and with the 250W array the controller steps up to a SmartSolar MPPT 100/30.

Panel kit or portable

The Renogy 200W 12V Starter Kit covers the 150W preset in one box. If you would rather not wire the trailer at all, the calculator's portable match for 474Wh a day over two days is the Jackery Explorer 2000 v2 at 2,042Wh. Whichever route you take, a SmartShunt turns these estimates into your real numbers after the first trip.

Run your own numbers in our RV solar & battery calculator. It opens with the travel-trailer preset filled in, so you only change what is different about your rig.