How much solar does a fifth wheel need for boondocking?

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

Short answer: A fifth wheel with a 12V compressor fridge, TV, laptop and a morning coffee maker uses about 832Wh a day. For two days that is 250W of solar and a 200Ah LiFePO4 bank. For three days of boondocking it needs 250Ah, and with three days of cloudy sun as well, a 400W array.

Boondocking means days, not a night, so the useful answer is how the system grows as the stay gets longer and the weather gets worse. These numbers come from the fifth-wheel preset in our calculator.

What the preset assumes

Load	Amp-hours a day (12V)
Lights, water pump, phone charging, vent fans	18
12V compressor fridge	25
TV or entertainment in the evening	8
Laptop for work or streaming	6
Morning coffee maker or microwave, through an inverter	8
Total	65Ah, about 832Wh

Five peak sun hours, parked with no alternator charging. The math uses a 12V bank, 85% usable LiFePO4 capacity, 75% real-world solar harvest and 92% inverter efficiency.

Solar and battery by length of stay

Stay and weather	Solar	Battery	Controller
2 days, mixed sun	250W	200Ah	MPPT 100/30
3 days, mixed sun	250W	250Ah	MPPT 100/30
3 days, cloudy or winter (about 3 peak hours)	400W	250Ah	MPPT 100/30
3 days, desert summer (about 6 peak hours)	200W	250Ah	MPPT 75/15 or 100/20
3 days with the furnace running at night	300W	300Ah	MPPT 100/30

The rule the table shows: the number of days sets the battery, and the sun sets the panels. A longer stay does not need more solar, because the array only replaces one day at a time. What it needs is enough battery to ride out the gap. Cloud is the opposite: same battery, more panel.

The furnace row is the one people miss. Ten amp-hours of blower a night adds 128Wh a day, which takes the three-day bank from 250Ah to 300Ah.

What to buy

Inverter: MultiPlus 2000VA, sized for the coffee maker or microwave at about 1,500W.
Array: the Renogy 400W 12V Starter Kit covers every row above, including the cloudy one.
Monitor: a SmartShunt, so you can see whether your fridge really averages 25Ah.

If you would rather not wire the trailer, the calculator's portable match for three days is the BLUETTI Apex 300 (2.5kWh needed over the stay).

Run your own numbers in our RV solar & battery calculator. It opens with the fifth-wheel preset filled in.