My first wiring diagram for the van was sketched on a corner of a pub table after three pints. Suffice to say it was imperfect. I crossed the panel polarities, forgot the fuse between the station and the panel, and wired the controller backwards. The station did not fry thanks to its internal protection, but I lost half a day working out why nothing functioned.
Since then I have redone the installation three times. Each iteration is better than the last. If you have not yet chosen your station, look at my guide on how many watts for a campervan first. This guide is the refined version -- the one I wish I had read before drilling my first hole in the roof.
Before talking cables and connectors, you need to understand how the different elements fit together. A van solar installation has three distinct zones that communicate with each other.
The roof zone is where the panels sit. They capture light and produce direct current (DC). Voltage depends on the panel -- typically 18-24 V for a 100-200 W panel, up to 40-50 V for two panels in series.
The transit zone is the passage between the roof and the interior. One or two cables passing through the roof via a waterproof cable gland. This is the critical point of the entire installation -- done poorly, it leaks, and moisture in a van means guaranteed mould.
The interior zone is the portable station (which integrates the MPPT controller, battery, and inverter) and everything plugged into it. This is the simplest part, because the station does the heavy electronic lifting.
And that is the great advantage of an installation with a portable station rather than separate components (battery + controller + inverter): you eliminate 80% of the wiring and 90% of the risk of error. No battery to wire up, no controller to configure, no inverter to connect. You plug the panel into the station solar input, and it is done.
Everything you need, with specifications and approximate prices for March 2026.
Solar panels. For a Ducato/Sprinter/Crafter-sized panel van, two rigid monocrystalline 200 W panels each is standard. Typical dimensions: 1050 x 540 x 30 mm per panel. Weight: roughly 8 kg apiece. Budget: 150-250 euros per panel. I use Renogy panels -- good value, solid aluminium frame, quality MC4 connectors.
Roof fixings. Aluminium Z-brackets (four per panel), stainless self-tapping screws, and polyurethane sealant (Sikaflex 252 or equivalent). Z-brackets create a 5-8 cm gap between panel and roof for ventilation -- essential for yield, as I explain in my article on real-world solar recharge times. Budget: 30-50 euros for both panels.
Cable gland. A 16 mm waterproof cable entry, Haldex type or equivalent. A threaded cylinder that screws through the roof with a silicone seal. One is enough for both cables (positive and negative). Budget: 10-15 euros.
Solar cable. 4 mm2 cable with UV-resistant sheathing. You need roughly 5-6 m (two runs: positive and negative, from panels to gland, then gland to station). Budget: 20-30 euros.
MC4 connectors. Four male/female pairs to connect panels to each other and to the main cable. Plus an MC4-to-proprietary adapter for your station (EcoFlow, Bluetti etc. usually supply this). Budget: 15-25 euros.
DC fuse. 15 A or 20 A depending on your panel power. Placed on the positive cable between panels and station. Protection in case of short circuit. Budget: 5-10 euros with the fuse holder.
The portable station. Your main component -- it integrates the MPPT controller, LFP battery, inverter, and BMS. See my other articles for model selection.
Total materials excluding station: 380-620 euros depending on panels chosen. The complete installation (panels + station) comes in between 1000 and 2500 euros depending on the station.
THE question everyone asks. Your two 200 W panels -- do you wire them in series or parallel? The answer depends on your station.
In series, you add voltages and keep the same current. Two 200 W panels at 20 V and 10 A in series give 40 V and 10 A, or 400 W. Advantage: current is low, so cable losses are low, and you can use thinner cable. Disadvantage: if one panel is partially shaded, both drop.
In parallel, you add currents and keep the same voltage. The same panels in parallel give 20 V and 20 A, or 400 W. Advantage: if one panel is shaded, the other keeps producing normally. Disadvantage: higher current, thicker cable needed, higher losses.
My recommendation for a van: series wiring. Why? Because most portable stations have an MPPT with a broad voltage range (typically 11-60 V) but limited input current (often 10-15 A). In series at 40 V and 10 A, you are in the MPPT sweet spot. In parallel at 20 V and 20 A, you risk exceeding the maximum input current.
ALWAYS check your station solar input specs before deciding. Look for MPPT min/max voltage and max current in the manual.
Before climbing onto the roof, prepare everything at ground level. Connect the MC4s, test voltage with a multimeter (you should read the panel nominal voltage, 20-24 V per panel). If wiring in series, verify that total voltage matches the sum. No voltage? Check polarities and connectors.
Also measure and cut your cables to the right length. Allow 30 cm of slack -- always easier to shorten than lengthen.
Clean the roof with degreaser. Critical -- sealant will not adhere to a dirty or greasy surface. Position the Z-brackets at each panel corner, mark locations with a marker, drill pilot holes. Apply a generous layer of Sikaflex to each foot, screw down, and leave for twenty-four hours.
Twenty-four hours. Not overnight, not "a few hours." The polyurethane needs that time to cure fully. If you move the van before then, the seal may detach. I made this mistake the first time -- drove off next morning, and after three days on the road one bracket was slowly working loose. Back to square one.
The moment everyone dreads. Drilling through the roof of your van hurts the soul. But it is necessary.
Choose a location as central as possible, above where the station will sit inside. The shorter the cable between roof and station, the better. Drill with a hole saw of the correct diameter (usually 16 mm). Deburr, treat bare metal with anti-rust primer, seat the gland with a generous Sikaflex bead all round, and tighten.
Test for watertightness immediately. A good test: place absorbent paper inside beneath the gland and hose the roof for five minutes. If the paper is dry, you are good. If not, redo the seal.
Fix panels to the Z-brackets. Route cables from panels to the gland, securing them to the roof with UV-resistant adhesive cable ties. Leave slack at each end to absorb vibrations.
Pass cables through the gland. Tighten the gland around the cables -- a good gland has a compression seal that prevents water wicking along the cable.
Inside, you have two cables hanging from the roof (positive and negative). Simple wiring.
Positive cable: DC fuse (15-20 A) then station solar input connector. Negative cable: directly to station solar input (negative terminal).
That is it. If your station uses a proprietary connector (XT60 on EcoFlow, Anderson on some models), use the manufacturer adapter or a purpose-made MC4-to-station cable.
Fix cables neatly along the wall with cable ties. No dangling cables -- in a van, anything that moves eventually wears through by friction.
Power on the station. The screen should show solar input power. In full sun, you should see a value close to 60-70% of your panel nominal power. With 400 W of panels in series, expect 240-300 W in good weather.
If you see 0 W: check polarities (the number one cause), check MC4s are fully clicked home, check the fuse is intact.
If you see a very low value (20-30 W with 400 W of panels): check series/parallel wiring and ensure panels are not shaded. Even partial shade on one panel crashes the entire system in series.
A question I get often: should you earth the van solar installation? Short answer: for a portable station setup, no. The station is galvanically isolated -- the internal inverter creates its own voltage reference. There is no electrical link between the van chassis and the station circuit.
However, if you mix a portable station with the van fixed electrics (hard-wired 12 V lighting, campsite 230 V hookup with a consumer unit), then chassis earthing becomes relevant. But that is outside the scope of this guide.
The cable gland is not the only option. There are three main methods.
The classic cable gland -- what I use and recommend. Clean, reliable, five minutes to install (excluding cure time). Only downside: you drill the roof.
Passing through a door or window seal. Some vanlifers thread a flat ribbon cable under the tailgate or window seal. Advantage: no drilling. Disadvantage: the cable is crushed at every opening, and flat cables have limited cross-section. I have seen flat cables fail after six months.
Passing through an existing vent. Some vans have roof or side vent grilles. You can feed a cable through with a small seal around it. Compromise option.
My recommendation remains the cable gland.
A van solar installation needs almost no maintenance. Almost.
Panels: clean monthly with clear water and a soft cloth. No chemicals, no pressure washer. In salty areas (seaside), clean more often.
Cables: visual inspection every six months. Check MC4s are seated, cables are not rubbing on metal edges, gland is still watertight. A Sikaflex refresh every two to three years as a precaution.
Fuse: check yearly. A DC fuse that has operated near its limit can develop rising internal resistance. At 2 euros a fuse, replace preventively each year.
Station: follow manufacturer recommendations. Generally, a battery calibration every two to three months (full discharge then full charge) helps maintain gauge accuracy.
No fuse between panels and station. The fuse costs five euros. Fit it.
Undersized cables. 2.5 mm2 over 8 m at 10 A = 7% loss. 4 mm2 = 4%. Use 4 mm2 minimum.
Poorly sealed gland. A water leak in a van causes rust, mould, and damage that costs far more than the installation itself.
Panels bonded without ventilation. Directly bonded panels overheat and lose 10-15% yield in summer. Z-brackets exist for a reason.
Sun -> Panel 1 (series) -> Panel 2 -> Positive cable -> Cable gland -> DC fuse 15 A -> Station solar input -> Integrated MPPT -> LFP battery -> Inverter -> 230 V AC sockets + USB + 12 V outputs
Negative cable -> Cable gland -> Station solar input (negative terminal)
The beauty of the portable station system: one piece of equipment replaces four separate components. Fewer cables, fewer failure points, fewer mistakes.
Two 200 W rigid panels: 400 euros. Fixings, gland, cables, connectors, fuse: 100 euros. 1000 Wh station (e.g. EcoFlow DELTA 3 Plus): 1400 euros. Total: 1900 euros.
An equivalent separate-component system costs 1500-2500 euros plus 500-800 euros for professional installation. With the portable station, you do it yourself in a day (plus cure time). And if you change vans, you unbolt the panels, unscrew the gland, and carry the station under your arm.
For an estimate of your expected solar output, try our solar calculator. The freedom to stop wherever you want, whenever you want, without worrying about electricity -- that is priceless. That is why we fit out vans, is it not?
Not with a portable station. The wiring is basic: two cables between panels and station, a fuse, a cable gland. If you can drill a hole and tighten a bolt, you can do it yourself in a day. An electrician becomes useful only if you want to mix portable station with fixed 12 V wiring.
4 mm2 solar cable minimum, UV-resistant sheathing, MC4 connectors. For runs over 6 metres, go to 6 mm2 to limit losses. Undersized cable means energy wasted as heat -- up to 7% loss with 2.5 mm2 over 8 metres.
Yes, provided you check the specs. In series, panels must have the same current (similar amperage). In parallel, the same voltage. Different brands with the same power and voltage work perfectly well together. Just verify the total voltage does not exceed your station maximum input.
Cedric
