Van Electrical Guide
How Much Solar Do You Actually Need?
Every van build eventually confronts the electrical question. How many solar panels? What size battery bank? Will it actually work off-grid? The answer depends entirely on what you're running. Here's how to figure it out — and what the real-world numbers look like.
List everything that uses electricity and estimate how many hours per day you'll run it. Here's what typical van loads look like:
Common Van Loads (Watts)
12V Compressor Fridge
30-50W (running avg)
LED Lights
2-10W per light
MaxxAir Fan (medium)
5W
Laptop Charging
60-100W
Phone Charging
10-20W
Starlink Mini
25-40W (continuous)
Diesel Heater
10-30W (while running)
Water Pump
60W (intermittent)
Induction Cooktop
1500-1800W
Coffee Maker (12V)
150-200W
Example Daily Calculation:
Your battery needs to hold enough energy for at least one day of use — ideally more to handle cloudy days. The math depends on battery type:
Lead-Acid (AGM)
Can only use 50% of capacity to protect battery life.
1,700 Wh ÷ 12V ÷ 0.5 = 283 Ah minimum
Lithium (LiFePO4)
Can use 80-90% of capacity safely.
1,700 Wh ÷ 12V ÷ 0.8 = 177 Ah minimum
Our Recommendation:
For serious off-grid use, we recommend 400-600Ah lithium capacity for most builds. This handles:
Solar needs to replace what you use each day. But solar panels don't produce their rated wattage all day — output varies with sun angle, clouds, temperature, and shading.
Real-World Solar Production
A 100W panel produces roughly 300-500 Wh per day in good conditions. In winter, shade, or cloudy weather, expect less. Use 4-5 sun hours as a planning estimate for most US locations.
Example Solar Sizing:
Daily use: 1,700 Wh
Sun hours: 5 (average)
Solar needed: 1,700 ÷ 5 = 340W minimum
In practice, we'd recommend 400-500W to account for inefficiencies and bad weather days.
Weekend Use
200-300W
Basic loads, charge at home
Extended Trips
400-500W
Most common setup
Full-Time / Heavy Use
600W+
Remote work, Starlink, AC
DC-DC Charger (Alternator)
Charges your house batteries while driving. Essential backup for cloudy weather. A good 40-60A DC-DC charger can add 40-60Ah per hour of driving — significant on travel days.
Shore Power (AC)
Plug into campground hookups or home outlet. A proper shore power setup with battery charger is useful when you have access — fills batteries fast and takes load off solar.
Generator (Backup)
For extended cloudy periods or emergency backup. Small inverter generators (Honda EU2200i, etc.) can run a battery charger. Not ideal for daily use, but good insurance.
Electrical is one of the most critical parts of a van build. We design and install complete solar and electrical systems — properly sized, safely wired, with quality components. Tell us how you'll use your van and we'll spec the right system.
Need help sizing your electrical system? Tell us what you want to run and we'll spec the right setup — solar, batteries, and everything in between.
ADDRESS:
6159 E Huntsville Rd, Fayetteville, AR 72701
PHONE:
(479) 326-9200
EMAIL:
info@ozkvans.com