Photovoltaic panels in a campervan are today the basis of energy independence. Your own solar installation allows you to charge the battery, refrigerator, lighting, and electronics without connecting to an electrical hookup. If you are converting a van into a camper or modernizing a caravan, you can do it yourself — a $12$ V installation with semi-flexible panels is simple, inexpensive, and completely safe, provided you observe a few rules.
In this guide, we show you step-by-step how to mount the panels, what components to buy, what the connection diagram looks like, and what to check after installation.
Electricity in a caravan and campervan: how to install photovoltaic panels?
Photovoltaic panels in a campervan are today the basis of energy independence. Your own solar installation allows you to charge the battery, refrigerator, lighting, and electronics without connecting to an electrical hookup. If you are converting a van into a camper or modernizing a caravan, you can do it yourself — a $12$ V installation with semi-flexible panels is simple, inexpensive, and completely safe, provided you observe a few rules.
In this guide, we show you step-by-step how to mount the panels, what components to buy, what the connection diagram looks like, and what to check after installation.
Why is it worth installing photovoltaic panels in a campervan?
Full off-grid independence (refrigerator, laptop, chargers, water pump).
No need to stay at campsites – energy is always with you.
Semi-flexible panels can be glued without drilling, which simplifies DIY installation.
2. Do panels in a caravan work the same way?
Yes – the electrical system is identical. Only the surface area and the cable routing differ.
In caravans, it is important to ensure thorough degreasing of the roof and a reduced point load (larger glued surfaces).
Solar panels in a caravan — where to start?
Photovoltaic panels are no longer a gadget today, but the primary power source for anyone who loves caravanning and vanlife. A well-chosen set ensures complete independence – even for many days without connecting to the grid. We opted for $100$ W semi-flexible panels – two units ordered on AliExpress (cost approx. 407 PLN/unit). They are light, thin, and can be glued without drilling the roof, which was key for us.
"This is our first solar panel installation, and probably our last," we joked at the beginning. But the result exceeded expectations – the panels still work today, and we draw electricity straight from the sun.
List of Components and Installation Cost
Semi-Flexible Solar Panels $100$ W (2 units) 407.00 PLN (Regular price 597 PLN, they lowered the price for us due to shipping from Spain, not from the Czech Republic, as stated in the auction).
AZO MPPT Controller $30 \text{ A}$ 449.00 PLN
Sikaflex Set (Activator, Primer, Sikaflex 252, Abrasive Sponge, Primer Sponge) 109.00 PLN
Sika 710 17.90 PLN
Sikaflex 252 51.50 PLN
Grey Tape 9.50 PLN
Mounting Elements 43.00 PLN
Connectors 12.00 PLN
Electrical Wire Ends 12.00 PLN
Battery Terminals 7.50 PLN
2-Module Housing 6.20 PLN
4-Module Housing (2 units) 15.00 PLN
16mm Cable (8m.) 51.00 PLN
16mm Cable (8m.) 65.00 PLN
Solar Cable (20m.) (WE USED ONLY 10m.) 80.00 PLN
Conduit 8.00 PLN
Mounting Foam 12.00 PLN
Cable Tie Mounts 6.00 PLN
Screws 2.00 PLN
UP22 Mounts (25 pcs.) 7.00 PLN
How to select the appropriate panels and controller?
Type of panels:
Rigid panels (cheaper, but heavier and higher).
Semi-flexible panels – ideal for caravan and bus roofs.
Portable folding panels – a good option for people who do not want to glue.
Controller:
Always choose MPPT, not PWM – it has higher efficiency (even by $25-30\%$).
We used the AZO MPPT $30 \text{ A}$, which allows two panels to be connected separately and has an additional output for lighting.
Step-by-step installation (part 1)
1. Surface preparation
We started by cleaning the roof – washing with dish soap, then sanding with an abrasive sponge, and degreasing with white spirit (extraction gasoline). We secured everything with masking tape so as not to stain the caravan. The roof was yellowish and heavily contaminated – the final result: a white, shiny spot where the panels would go. That's when we knew we'd wash the whole caravan.
2. Panel preparation
The panels were new, so we only wiped and matted the bonding surface. Next: Activator (orange cap) Black Primer – a thin, even layer (preferably with shorter movements, transversely to the panel) Structural Adhesive – quite thick, especially at the roof's embossments.
3. Gluing and pressing
We pressed the panels down with blocks, and ran a finger with glue along the edges. We left them to dry for several days (the manufacturer recommends a minimum of $24 \text{h}$). We routed the cable connections through conduit and the roof gland, sealing them with silicone.
Electrical installation
We mounted the controller in the cupboard, right next to the fuse box.
We routed the wires in conduit next to the heating pipe, but insulated so they wouldn't heat up.
Electrical installation – parameters and wire selection
Connections + fuses + cable cross-sections
PV Panels 2 x100 (Parallel connection) → fuse → MPPT
Current from 1 panel: ~5,5–6 A (STC).
2 units in parallel: max approx. 12 A.
Fuse on the PV positive: 10-15A (for 2x100 W choose 15 A, if you are working in the summer sun).
Przewód PV → MPPT: 4 mm² up to 5 m total path length; for longer sections 6 mm².
Note: if someone connects panels in series, the fuse can be 15–20 A, but the wire and grommet must have a voltage reserve (V sums up).
MPPT (PV1/PV2 input) → fuse → battery
Controller: AZO MPPT 30 A.
Fuse on the MPPT → battery positive: 16-20 A (for 2×100 W in 12 V).
MPPT → battery Wire: 6 mm² (up to 2–3 m path); for longer sections 10 mm².
Rule: keep the controller as close as possible to the battery to limit voltage drops.
Battery 12 V (AGM/LiFePO₄) → 12→230 V Inverter
Inverter 300W:
Fuse near the terminal +: 30–40 A.
Wires: 10 mm²
Inverter 600W:
Fuse: 60–80 A.
Wires: 16 mm²
Inverter 1000W:
Fuse: 100–120 A.
Wires: 25 mm²
Fuse always as close as possible to the battery (max 15–20 cm from the terminal).
LOAD output from MPPT → LED
This output has its own MPPT protection, but still use a 1.5-2.5 mm² wire + a 5–10 A fuse at the branches.
Mounting tips (electrics)
Permissible voltage drop: aim for ≤ 3 % for charging circuits and ≤ 5 % for loads.
Plus/minus path: run in separate conduits over long distances; short passages together are OK.
MC4 connectors: original or branded; pressed with MC4 crimping tool, not pliers.
Terminals at the battery: copper lugs, crimped with a press + heat-shrink tubing.
Inverter grounding: according to the manufacturer's instructions (GND screw to the chassis ground, if provided).
MPPT connection order: first the battery, then the panels; when disconnecting, the reverse.
Mounting tips (panel gluing)
- Sequence: activator → primer → adhesive → pressing; 24–72 h drying.
Roof and gland seals: UV-resistant silicone/adhesive, degrease surfaces thoroughly.
Roof gland: with a "roof" (cover), filling the interior with silicone + additional external seal.
Running cables on the roof: UV-resistant adhesive clips; short cable sections in conduit.
Quick cross-section mapping (mm² ↔ AWG)
We mounted the controller in the cupboard, right next to the fuse box.
We routed the wires in conduit next to the heating pipe, but insulated so they wouldn't heat up.
4 mm² ≈ AWG 11
6 mm² ≈ AWG 9
10 mm² ≈ AWG 7
16 mm² ≈ AWG 5
25 mm² ≈ AWG 3
How to install photovoltaic panels in a caravan?
QUICK SUMMARY OF WHAT YOU SAW IN THE VIDEO
Step 1: Choosing the right photovoltaic panels
Different types of photovoltaic panels are available on the market, but for campers and caravans, semi-flexible panels are usually the best choice. They are light, thin, and flexible, which makes them easier to mount on the roof curves of the vehicle. Many people also choose rigid panels, but we decided on semi-flexible ones.
Step 2: Determining the mounting location
Before starting the installation, you must precisely determine the location where the photovoltaic panels will be mounted. The best place is a flat area on the roof of the camper or caravan that will receive maximum sunlight for most of the day. Here, each of you must decide where to place them; the important thing is that the surface is flat and even, because we have to glue them.
NOTE: Remember to exercise caution during installation to avoid damaging the vehicle and the panels.
Step 3: Preparing the mounting surface
Next, the surface on which the photovoltaic panels will be mounted must be prepared. Make sure the surface is clean (well degreased), dry, and smooth.
Step 4: Mounting the photovoltaic panels
In the first stage, we prepare the roof:
• First, we marked the target location for gluing the panels using a pencil.
• Next, we washed the roof with dish soap to degrease it as thoroughly as possible.
• Next, using a special abrasive sponge, we matted the surface.
• We matted the entire surface with extraction gasoline to remove dust and finally degrease the whole thing.
• Next, we secured the surface around the gluing area with grey tape to avoid staining the rest of the roof.
• Later, we apply the activator (a small bottle with an orange cap).
In the second stage, we prepare the panels:
• We wash the panels with dish soap.
• Next, we lightly matt, degrease, apply the primer with the orange cap, and finally the black activator.
We return to the roof:
• We apply the black activator; we used the sponge included in the set. The manufacturer recommends doing this with uniform, sweeping movements, without lifting the sponge from the surface.
Now we skip to the edge of the caravan and install the gland (cable feed-through); we drill a hole, try fitting the gland, and also tape around it to avoid unnecessarily staining the edges. For the third time, we repeat the same steps, i.e., wash, matt, degrease, apply the primer with the orange cap, and finally the black activator.
We proceed to applying the adhesive. We recommend a quite thick layer; we press down firmly and weigh it down with something—we chose a paving stone, but you can use several old bricks.
We return to the gland; once the activator has taken effect, we thread the cables into the conduit, and sealed around them with silicone—it is important that the silicone is suitable for indoor and outdoor use.
We apply the black activator to the roof and the adhesive to the gland. We glue it to the roof.
We return to the panels, and at this moment, we peel off the grey securing tape, because we decided to leave the panels for longer so that everything dries well, and we did not want this tape to vulcanize.
We returned to the panels after 3 days. The adhesive cured perfectly. Everything is holding very well.
Step 5: Connecting the photovoltaic panels
After gluing the panels, they should be connected using appropriate cables and connectors, fuses should be added, and generally, all the electrical wiring should be run. Make sure the connections are solid and there is no play.
Step 6: Testing and maintenance
Regularly check the condition of the panels and perform maintenance to ensure their optimal performance throughout the entire journey. Remember that they need to be washed every once in a while to ensure the charging level is maximal.
Installing semi-flexible photovoltaic panels in a camper or caravan can be an excellent way to increase independence from electric energy and enjoy travel without the need to constantly look for electricity.
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