A truck camper roof usually has room for two to three 200W panels, and that’s enough to keep a 12V fridge, lights, a fan and phones charged indefinitely in good sun. The panels I use for these examples are BougeRV’s Arch Pro 200W flexible panels. BougeRV rates each one at 31.1V Vmp and 36.4V Voc, at 7.9 lb and 53 × 31 inches, so two in series still fit under a 100V charge controller. This guide walks through a complete truck camper solar setup, from sizing the array and choosing the controller to wiring, fusing and mounting. Every number is shown so you can adapt it to your camper.
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Panel specs come from BougeRV. The system sizes, wire gauges, fuse sizes and energy figures are typical examples and my estimates, not a wiring plan for your specific camper. Have a qualified installer check your final design.
Step 1: Add up your daily energy
Start with what you’ll run. Here’s a typical truck camper day for two people. Your numbers will differ, so swap in your own devices.
| Load | Daily use | Energy per day (estimate) |
|---|---|---|
| 12V compressor fridge | Cycling all day | ~400Wh |
| LED lights | 4 hours at 15W | ~60Wh |
| Roof vent fan | 8 hours at 20W | ~160Wh |
| Water pump | 30 minutes at 60W | ~30Wh |
| Phones, tablet, camera | Daily charging | ~60Wh |
| Furnace blower (cool nights) | 2–3 hours | ~150Wh |
| Laptop or Starlink Mini | 3 hours | ~120Wh |
| Total | ~980Wh/day |
If you’re working in amp-hours, divide by 12.8V for a LiFePO4 bank: about 77Ah a day here.
Step 2: Size the array
A rough rule for planning: a panel makes about its rated watts × 5 sun hours × 75% on a good summer day (estimate). The 75% covers heat, flat mounting, dirt and controller losses. A flat-mounted panel on a camper roof does worse in winter and under trees.
| Array (Arch Pro 200W) | Roof area (approx.) | Good-sun day (estimate) | Cloudy day at ~25% (estimate) |
|---|---|---|---|
| 1 panel (200W) | ~11.4 sq ft | ~750Wh | ~190Wh |
| 2 panels (400W) | ~23 sq ft | ~1,500Wh | ~375Wh |
| 3 panels (600W) | ~34 sq ft | ~2,250Wh | ~560Wh |
For the ~980Wh day above, 400W covers sunny days with margin. 600W gives you headroom for partly cloudy weather or shade. Many truck camper roofs fit two full-size panels around the vent and AC (if you have one), and some fit three.
Step 3: Pick the battery
The battery carries you through nights and cloudy stretches. A 12V 200Ah LiFePO4 bank holds about 2,560Wh, roughly 2.5 days of the example load with no sun at all (estimate). A single 100Ah battery (1,280Wh) works for lighter users or anyone with alternator charging. LiFePO4 weighs about a third as much as lead-acid for the same usable energy, which matters on a truck already near its payload. My 100Ah battery runtime guide walks through the math.
Step 4: Choose the charge controller
Use an MPPT controller. Flexible and rigid 200W panels run at about 31V, well above a 12V battery, and an MPPT converts that extra voltage into charging current. A PWM controller can’t do that. See MPPT vs PWM for the reasons.
Two numbers decide the controller:
- Max PV voltage: the array’s Voc, plus a cold-weather margin, must stay under it.
- Output current: array watts ÷ battery voltage.
| Array | Wiring | Array Voc (BougeRV spec) | Cold-weather Voc (estimate, +10%) | Charge current at 12.8V (estimate) | Controller example |
|---|---|---|---|---|---|
| 2 × 200W | Series | 72.8V | ~80V | ~31A | 100V / 40A |
| 2 × 200W | Parallel | 36.4V | ~40V | ~31A | 75V+ / 40A |
| 3 × 200W | Series | 109.2V | ~120V | ~47A | 150V / 50–60A |
| 3 × 200W | Parallel | 36.4V | ~40V | ~47A | 100V / 50A |
I run my own Arch Pro panel into a SunSwift 60A MPPT rated for 150V, which leaves room to add panels in series. For Victron controllers, my Victron MPPT sizing guide has a full table.
Series or parallel? Series keeps current low, so you can use thinner roof cable, and it starts charging earlier in the morning. Parallel handles partial shade better, since a shaded panel doesn’t drag down the whole string. On a camper roof with a vent or a Starlink dish casting shade, parallel can win. My series vs parallel guide goes deeper.
Step 5: Wire it
Here’s the order of components from roof to battery:
- Panels on the roof, connected in series or parallel with MC4 connectors (and MC4 branch connectors for parallel).
- Roof entry gland to bring the cables through the roof without leaks.
- PV disconnect (a DC breaker rated for the array voltage) so you can isolate the panels.
- MPPT charge controller, mounted vertically with airflow, as close to the battery as practical.
- Fuse or breaker between the controller and the battery positive.
- Battery, ideally through a busbar or a fused distribution block.
| Run | Typical current | Example cable (estimate; check voltage drop) | Protection (estimate) |
|---|---|---|---|
| Panels → controller, 2S | ~6.7A | 10 AWG PV wire | PV disconnect breaker |
| Panels → controller, 3P | ~20A | 10–8 AWG PV wire | PV disconnect; string fuses per the panel’s 15A series fuse rating |
| Controller → battery, 40A | 40A | 6 AWG for short runs | 50A fuse near the battery |
| Controller → battery, 60A | 60A | 4 AWG for short runs | 80A fuse near the battery |
BougeRV lists a 15A series fuse rating for the Arch Pro. With three or more strings in parallel, fuse each string. Check every cable against my wire gauge chart and my fuse sizing guide. Connect the controller to the battery first, then the panels, so the controller can detect the system voltage.
Step 6: Mount the panels
Truck camper roofs are often aluminum or fiberglass, sometimes slightly curved, and every pound counts. That’s why flexible panels are popular. At 7.9 lb and about 0.1 inches thick, the Arch Pro can follow a gentle curve (BougeRV says up to 270° of flex) and adds little weight. You have three common options:
- Adhesive or sealant directly on the roof: low profile and light, but permanent and with no airflow behind the panel, so it runs hotter.
- Bonded to a thin board or rails: adds airflow and makes removal possible.
- Bolted through the hanging holes onto a rack: best cooling and fully removable.
I cover the panel itself, including an off-grid Starlink power test, in my Arch Pro 200W review. Whichever you choose, seal every roof penetration with a self-leveling lap sealant made for your roof material, and leave the panel leads slack so they don’t pull at the connectors as the camper flexes on rough roads.
Step 7: Program and test
- Set the controller’s battery type to LiFePO4, or enter the battery maker’s absorption (often 14.2–14.6V) and float (often 13.5V) values.
- Check the array voltage at the controller in sun: about 62V for 2S, 31V for parallel (estimate).
- Watch the charging current at midday. Around 75% of the array rating is normal on a flat roof.
- Add a battery monitor (shunt) if you want accurate state-of-charge readings.
Example parts list: 400W truck camper system
| Part | Example spec | Qty |
|---|---|---|
| Solar panels | BougeRV Arch Pro 200W (31.1V Vmp, 36.4V Voc) | 2 |
| Charge controller | MPPT, 100V+ PV input, 40A+ output | 1 |
| Battery | 12V 200Ah LiFePO4 (or 2 × 100Ah in parallel) | 1 |
| PV cable | 10 AWG PV wire, red and black, length to suit | 1 set |
| Roof entry gland | Two-cable, sized for 10 AWG | 1 |
| PV disconnect | DC breaker rated above array Voc | 1 |
| Battery-side fuse | 50A, with holder, near battery positive | 1 |
| Battery cable | 6 AWG with crimped lugs (short run) | 1 set |
| Sealant | Self-leveling lap sealant for your roof material | 1–2 tubes |
| Battery monitor (optional) | Shunt-based monitor | 1 |
Crimp lugs with a proper hydraulic or ratcheting crimper, and use heat-shrink on every termination. Vibration on washboard roads is hard on loose connections.
Add alternator charging
Most truck campers drive often, and a DC-DC charger from the truck’s alternator fills the gaps solar can’t. A 30A DC-DC charger adds roughly 380Wh per hour of driving (estimate), and it’s especially useful in winter and on wooded campsites. If your truck has a smart alternator, choose a DC-DC charger that supports it.
BougeRV Arch Pro 200W flexible panel on Amazon
FAQ
How much solar do I need on a truck camper?
For a 12V fridge, lights, a fan and devices (about 1kWh a day), 400W covers sunny days. 600W adds margin for clouds and shade.
Should I wire truck camper panels in series or parallel?
Series uses thinner cable and starts charging earlier. Parallel copes better with shade. Two Arch Pro 200W panels in series (72.8V Voc) fit a 100V controller. Three in series need a 150V controller.
Are flexible panels good for truck campers?
They’re light (7.9 lb for an Arch Pro 200W) and follow curved roofs. Mounting them on a board or rack with an air gap helps them run cooler.
What size charge controller for 400W of solar?
About 31A at 12.8V, so a 40A MPPT. Check the controller’s max PV voltage against the array Voc plus a cold-weather margin.
Do I still need a DC-DC charger with solar?
It’s optional, but helpful. Solar covers sunny days, and a DC-DC charger refills the battery while you drive in poor weather.