Installing RV roof solar comes down to four stages: mount the panels, run the wiring through a weatherproof roof gland, connect through a fuse to an MPPT charge controller, then wire the controller to your battery. A typical 2-panel install takes a day with basic tools. This guide covers the order of operations, series vs parallel wiring, and the safety steps that protect your roof and your battery.
What you'll need
- Solar panels (see the RV solar panel buying guide to size your array)
- An MPPT charge controller sized to your array — see MPPT vs PWM and shop charge controllers
- PV cable, MC4 connectors, a roof entry gland, and mounting brackets/Z-brackets or adhesive mounts
- A PV-side fuse or breaker and a battery-side fuse — see fuses
- Sealant (self-leveling lap sealant for the roof), cable lugs, and a crimp tool
Step 1 — Plan the layout (dry-fit first)
Lay the panels on the roof and plan around vents, antennas and the AC unit. Leave room to walk and for airflow under the panels. Mark bracket positions, and choose the shortest sensible path to where the wiring will drop into the camper (near the battery/controller location).
Step 2 — Mount the panels
- Attach brackets to the panels, then position on the roof.
- Fix to the roof per your roof type — screwed Z-brackets into structure, or adhesive mounts for no roof penetrations. Bed every bracket and screw in sealant.
- Seal all fasteners with self-leveling lap sealant to keep the roof watertight.
Step 3 — Run the wiring (series vs parallel)
Connect the panels, then route the output through the roof gland.
- Series raises voltage and lowers current — smaller cable, better for long runs and MPPT controllers.
- Parallel keeps voltage low but the array keeps producing if one panel is shaded.
- Series-parallel balances both on larger arrays.
Mount the roof entry gland over the cable hole and seal it well — this is the most common leak point.
Step 4 — Wire the charge controller & fuses
Order of connection matters for an MPPT controller: connect the battery first, then the panels.
- Connect the controller's battery terminals to the battery, through a fuse close to the battery.
- Then connect the PV terminals to the panel array, through a PV-side fuse/breaker.
- Set the battery type (e.g. LiFePO4) in the controller or VictronConnect.
For exact cable gauge and fuse ratings, see our Victron cable & fuse sizing chart.
Step 5 — Test & commission
- In daylight, confirm the controller shows PV voltage and is charging.
- Check connections for heat after an hour of charging.
- Confirm your battery monitor shows current flowing in.
Building the rest of the system? See how to build a Victron off-grid power system and how to size your lithium battery bank.
Common mistakes to avoid
- Connecting panels to the controller before the battery — always battery first on MPPT.
- Skimping on roof sealant — every penetration is a future leak if not bedded and lapped.
- No PV-side or battery-side fuse — fuse both sides.
- Oversizing the array for the controller — match panel watts/voltage to the MPPT's rating (see the pairing chart).
Frequently asked questions
Do I have to drill into my roof?
Not always — adhesive mounts avoid penetrations on suitable roofs. If you screw brackets in, bed every fastener in sealant and lap-seal the top to keep the roof watertight.
Series or parallel for my panels?
Series suits MPPT controllers and long runs (higher voltage, smaller cable); parallel keeps producing if one panel is shaded. Many installs use series-parallel.
What size fuse do I need?
Fuse both the PV side and the battery side to the cable's ampacity. See the cable & fuse sizing chart for the exact values for your array and controller.
Can I add a panel later?
Yes, if your controller has headroom for the extra watts/voltage. Check the controller's max PV input before expanding — the pairing chart shows how to match them.
Ready to fit your array? Shop MPPT controllers, fuses and solar gear — in stock, ships from Upland, CA.