What size battery and solar does a truck camper need?

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

Short answer: A truck camper with a 12V compressor fridge and a laptop uses about 627Wh a day. Our calculator sizes that at a 150Ah LiFePO4 battery for two days, and because an hour of driving through a 30A DC-DC charger puts back about 27Ah, only 100W of solar. Parked with no driving, the array grows to 200W.

A truck camper rides on its own charging source. The truck's alternator is right there, so the calculator's truck-camper preset counts on an hour of driving a day and sizes the solar around what is left.

What the preset assumes

Load	Amp-hours a day (12V)
Lights, water pump, phone charging, vent fans	18
12V compressor fridge	25
Laptop for work or streaming	6
Total	49Ah, about 627Wh

Two days between recharges, about five peak sun hours, about an hour on the road a day. The math uses a 12V bank, 85% usable LiFePO4 capacity and 75% real-world solar harvest.

The result

Battery: 150Ah. Two days at 49Ah is 98Ah, and 85% of 150Ah covers it.
DC-DC charger: Orion-Tr Smart 30A, about 27Ah back per hour of driving.
Solar: 100W. The alternator covers 27Ah, leaving 22Ah a day for the panel.
Controller: SmartSolar MPPT 75/15 or 100/20.
Inverter: none. Every load in the preset is 12V.

If your camper roof has little free space, the DC-DC charger is the part that matters most. It turns drive time into charge without using any roof.

What changes the answer

Change	Daily use	Solar	Battery
Preset as above	627Wh	100W	150Ah
Parked, no driving	627Wh	200W	150Ah
Furnace or diesel heater at night	755Wh	150W	150Ah
Three days between recharges	627Wh	100W	200Ah

Parking up doubles the array because the alternator's 27Ah has to come from the sun instead. A longer stay grows the battery and leaves the panels alone.

Kit or portable

The Renogy 200W 12V Starter Kit covers either array size. For a camper you would rather not wire, the calculator's portable match is the Renogy 2-in-1 Smart PowerMax: 1,280Wh against about 1.3kWh over two days, so it fits if you drive most days. It can also become a 12V 100Ah house battery if you wire the camper later. Add a SmartShunt to a wired build so you can see real numbers.

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