How much solar and battery does a Class B camper van need?

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

Short answer: A van with a 12V compressor fridge, a laptop and a Starlink Mini or cell booster uses about 883Wh a day. For two days off-grid that is a 200Ah LiFePO4 battery, and with an hour of driving a day through a 30A DC-DC charger, only 150W of solar. Park for days at a time and the array grows to 250W.

Vans are the one rig type where the alternator does a real share of the charging, so the answer depends as much on how you travel as on what you run.

What the van 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
Starlink Mini or a cell booster, on most of the day	20
Total	69Ah, about 883Wh

Two days between recharges, about five peak sun hours, and 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: 200Ah. Two days at 69Ah is 138Ah, and 85% of 200Ah covers it.
DC-DC charger: Orion-Tr Smart 30A. One hour of driving puts about 27Ah back.
Solar: 150W, because the alternator has already covered 27Ah of the 69Ah.
Controller: SmartSolar MPPT 75/15 or 100/20.
Inverter: none. Everything in the preset runs on 12V, so you skip the inverter's idle draw.

Driving is the biggest lever

How you travel	Solar	Battery
Park for days, no driving	250W (MPPT 100/30)	200Ah
About an hour a day	150W	200Ah
Two hours a day	100W	200Ah

Notice the battery does not shrink. The calculator credits driving against the array, not the bank, because the battery still has to carry you through the nights and the days you do not move.

Two common additions

A Standard Starlink dish instead of the Mini: 1,203Wh a day, 250Ah and 250W.
A morning coffee maker or microwave: 986Wh a day, 200W, and now a MultiPlus 2000VA inverter, since that load peaks around 1,500W.

If you would rather not wire the van

The calculator's portable match for the van preset is the Jackery Explorer 2000 v2 (2,042Wh against about 1.8kWh over two days). The Renogy 200W 12V Starter Kit covers the 150W array if you do build it in, and a SmartShunt shows what the system is really doing once you are on the road.

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