Van solar installation
Rigid or flexible panels, an MPPT charge controller sized to the array, and a roof plan that leaves room for your fan and AC.
IllustrationSize it from your loads, not the roof
The most common solar mistake is buying panels to fill the roof and hoping it covers your use. We size it the other way around: start with how much energy you use per day, work out how much of that solar should cover in the seasons you travel, then fit the array and controller to that and to the roof space left after fans and AC.
A rough example. A van running a 12V compressor fridge, lights, a fan and charging laptops and phones often uses somewhere around 1 to 2 kWh a day. A 400W rigid array laid flat on a Sprinter roof might deliver roughly 1.2 to 1.6 kWh on a clear Utah summer day, and well under half that in December when days are short and the sun is low. That's why most vans pair solar with alternator charging for travel days, and why we size the battery bank to ride through cloudy stretches.
Every array feeds a Victron SmartSolar MPPT sized for the array's voltage on the coldest morning and its current at full sun, with one sealed roof gland and fusing at the right points. We usually mount rigid N-type panels on a rack, which keeps them cooler and more productive; flexible panels are an option for stealth builds.
Side section through a rack-mounted array. Air under the panels keeps them cooler and more productive, and a single sealed gland brings the cable inside.
- 1Rigid panels cooler running on a rack
- 2Rack and rails factory roof mounting points
- 3Sealed roof cable gland one penetration, sealed
- 4MPPT controller sized for cold-morning panel voltage
- 5Battery
How we size a solar system
Three numbers decide the system. We work through each one with you.
1. Daily energy budget
What you run and for how long, in watt-hours per day.
- Fridge, fans, lights and device charging set the baseline
- Induction cooking, AC and heaters change everything
- Tells us how big the battery bank needs to be too
Best for: Start here. We build the list with you.
2. Array size and roof space
How many watts of panels the roof can carry after fans, AC and decking.
- Real yield is well below the label: heat, flat mounting and shade all cut it
- Utah summer sun is strong; winter output drops sharply
- A Sprinter high roof usually limits how big you can go
Best for: Solar should cover parked days; the alternator covers driving days.
3. Controller and wiring
Victron SmartSolar MPPT sized in volts and amps.
- Voltage: panel open-circuit voltage rises 10 to 15 percent on cold Utah mornings, so the controller's rating must clear it
- Amps: array watts divided by battery voltage
- Series vs parallel wiring set by shade and controller limits
Best for: Get this wrong and a cold morning can destroy the controller.
How we do it
Plan the roof
Panels laid out around the fan, AC, rack and decking to avoid shade.
Mount
Panels on the rack or rails, or bonded flat for flexible panels.
Bring it inside
Cable through a single sealed roof gland bedded in sealant.
Protect and control
PV fusing, a disconnect and an MPPT sized to the array's cold-weather voltage.
What to know before you buy
Watts on the label aren't watts per hour
Heat, flat mounting, shade and short winter days all cut output. Treat the rating as a ceiling.
Cold voltage
Panel voltage climbs in the cold. In Utah that can add 10 to 15 percent, so the controller has to be sized for it.
Roof real estate
Decide fans and AC first. Panels are the easiest thing to fit around them.
Questions about solar
How much solar do I need?
Enough to cover your daily energy budget on the days you're parked in the season you travel. We start from your load list, then check what fits on the roof and plan alternator charging for the gap.
Why does my solar make less than the panel rating?
Panel ratings are lab numbers. Heat, flat mounting, shade, dust and low winter sun all reduce real output, often a lot.
Rigid or flexible?
Rigid on a rack for most builds. Flexible when stealth or weight matters most.
Can you add panels to my existing system?
Yes. We check that your controller's voltage and amp ratings can take the bigger array before adding.
Get a solar quote
Send a few details and we will call you back with ideas, options and a ballpark.
- 6771 Emigration Canyon Rd, Salt Lake City
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