Solar for travel trailers and fifth wheels

A 30-foot travel trailer or a 35-foot fifth wheel has a long, mostly flat roof with fewer intrusions than a Class A motorhome: usually one or two AC units, a few vents, and no engine-related hardware. That typically leaves room for 600–1,000 W of panels, and some full-profile fifth wheels take more. Bunkhouse models with a second AC lose some of that. Because the roof is high and the membrane is often soft EPDM or TPO, mounting is a job for someone who has sealed a trailer roof before; a leak in year three costs more than the array did.

Flat-mounted at Front Range latitude, an 800 W trailer array makes roughly 3–4 kWh on a clear summer day and 1–1.5 kWh in December. That runs LED lighting, the water pump, the furnace blower on cold nights (a real load, often 0.5–1 kWh per night), a fan, and electronics, with the fridge on propane. As with every RV, the air conditioner is the honest limit: 1.2–1.5 kW running, hours at a time, so campground power or a generator for AC.

Most Colorado trailers sit at home from October to May. Plugged into a 30-amp (TT-30) or 50-amp (14-50) outlet at the pad, the onboard converter float-charges the batteries and, if you leave the propane on, the fridge can be kept cold before a trip. The parasitic draw is small — tens of watts for the converter, more if you run a tank heater or a dehumidifier — but it is continuous, which is exactly the kind of load a rooftop system on the house covers without you noticing.

That pad outlet is ordinary residential electrical work and fits naturally into a solar project; the 14-50 receptacle is also what many EV chargers use. If your HOA restricts where a trailer can park, note that Colorado’s solar-access law (C.R.S. 38-30-168) protects solar on the building, not the vehicle, so the parking rules still apply. We size the home array from your annual usage, trailer included, and the trailer’s own electrical stays with an RV shop.

Lead-acid batteries are the ones that die in storage. A discharged lead-acid battery can freeze and crack at temperatures the Front Range hits every January; a fully charged one is fine to well below zero. The options, in order of effort: leave the trailer on shore power with the converter maintaining the batteries, pull the batteries and store them on a maintainer in the garage, or fit a small 20–50 W maintainer panel with its own controller if the trailer stores away from power. Rough market cost for a maintainer panel kit is $50–$200; prices vary.

Lithium is easier: store it at roughly half charge, disconnect it, and it will sit for months with negligible loss. It should not be charged below about 32°F, so if you leave a lithium bank connected to a maintainer over winter, make sure the battery has a heater or the charger has a low-temperature cutoff. Either chemistry benefits from a battery disconnect switch so the propane detector and stereo memory don’t drain it over five months.

A trailer stored outdoors in Weld, Adams, Arapahoe, or El Paso County will see hail. Rigid panels use tempered glass and are commonly tested to roughly 1-inch stones; a bad Front Range storm throws larger, and the roof membrane and skylights around the panels are usually the first casualties anyway. A steel RV cover or carport is the real protection, and it also stops UV from chalking the panels and the roof sealant. Rough market cost for a metal RV carport is a few thousand dollars, and prices vary by size and county permitting.

Check your insurance policy for how roof-mounted equipment is treated, and photograph the array when it goes on. For a trailer that lives on the Western Slope or in the mountains, snow load matters more than hail: brush the panels rather than scraping them, and don’t let two feet of wet March snow sit on a roof that was never meant to hold it.

Campground-to-campground with hookups: solar is mostly a convenience for travel days, and a 200–400 W roof plus the stock batteries is plenty. State-park loops without hookups for long weekends: 400–600 W and 200 Ah of lithium runs the furnace and lights for three or four nights. Extended boondocking on forest land: fill the roof, go to 300–400 Ah of lithium, and add a 2,000–3,000 W inverter for the microwave and coffee maker. Complete lithium-and-solar upgrades from an RV shop typically run into the low thousands of dollars for a modest system and higher for a full roof; prices vary.

Whatever the tier, count the furnace. Colorado nights in May and September at 8,000 feet get to freezing, the blower runs for hours, and it’s the load that empties a lead-acid bank by 4 am. The fridge on propane, the lights on LED, and the furnace budgeted honestly is a trailer that solar keeps happy for a week.