Nomad energy 12 min read

Camper van solar setup 2026 — The complete guide: sizing, wiring and real-world pricing

By Azimut AI · March 20, 2026 · Updated October 14, 2026 · Our editorial policy

A badly sized solar system means a fridge that dies after 3 days, an underused MPPT, and €600 wasted. This guide gives you the exact formulas, product comparisons based on manufacturer datasheets, and the 7 most common mistakes.

400 Wc

standard full-time van setup

0,78

residential Performance Ratio (IEC 61724)

€1 580

complete full-time config budget

+29%

measured MPPT vs PWM gain

1. Work out your real needs — the Wp formula

The first sizing mistake always starts here: people eyeball it and undersize by 40%. List every device with its power draw (W) and daily use (h/day).

Equipment	Power	Use/day	Wh/day	Type
40 L compressor fridge	45 W avg.	24h	480–880 Wh	Critical
Laptop 15"	45–65 W	5h	225–325 Wh	Variable
External monitor 24"	22 W	4h	88 Wh	Variable
LED lighting (4 strips)	20 W total	4h	80 Wh	Low
Smartphone + tablet	15 W	2h	30 Wh	Low
Drone charging	60 W	1h	60 Wh	Occasional
12V water pump	6 W	0.3h	2 Wh	Negligible
TYPICAL TOTAL (full-time van)			965–1 465 Wh/day

Wc sizing formula

Wc = (Wh/day × 1,25) ÷ PSH

PSH = Peak Sun Hours (source: PVGIS). 1.25 = safety coefficient (wiring + MPPT + temperature losses).

Example: full-time van, 1 200 Wh/day, central France (PSH = 4.5h) → Wc = (1 200 × 1,25) ÷ 4,5 = 333 Wc → pick 400 Wc

Your appliances, your destination, your month: the calculator works out the solar output, the watts of panels and the battery you need.

Size your panels and battery month by month

2. Flexible vs rigid panels — 2026 comparison

Criterion	Flexible	Rigid	Winner
Efficiency	18–21%	22–23%	Rigid
Warranted lifespan	10–15 years	25 years	Rigid
Weight (200 Wc)	2,4 kg	13–16 kg	Flexible
Curved-roof mounting	✓ Glue + screws	✗ Brackets	Flexible
Ventilation	Glued → +15°C → -8%	Ventilated → stable	Rigid
Price per Wc (2026)	€1,50–2,00/Wc	€0,90–1,40/Wc	Rigid
Hail/impact resistance	Moderate	High (3mm glass)	Rigid

The glued-flexible trap: with no air gap, a flexible panel reaches 85°C → efficiency -10%, lifespan halved. Mount on spacer rails of 2–3 cm minimum.

3. MPPT controller — why you should never pick a PWM

A PWM wastes 20-30% of the energy produced. On 400 Wc, that's 400-600 Wh lost per day.

MPPT vs PWM gain — real-world example

200 Wc panel, Voc = 22V, Vbatt = 13.2V

PWM: 200/13.2 × 0.75 = 11,4A → 150W effective

MPPT: 200 × 0.97 = 194W effective — i.e. +29%

Controller	Current	Price	Connectivity	Verdict
Victron SmartSolar MPPT 40A	40A	€145	Bluetooth + app	Market reference
Renogy MPPT 40A	40A	€85	LCD only	Good value
EPEver Tracer 40A	40A	€70	RS485 optional	Budget
Victron SmartSolar 100/50	50A	€180	Bluetooth + VE.Direct	400+ Wc recommended

4. LiFePO4 battery — what capacity to choose?

LiFePO4: 10× more cycles, 50% lighter, 100% usable capacity (vs 50% for AGM).

Battery capacity formula

Ah = (Wh/day × Days of autonomy) ÷ (V × DoD)

DoD = 0.8 for LiFePO4 / 0.5 for AGM. Example: 1 200 Wh/day × 2 days ÷ (12 × 0,8) = 250 Ah

5. Wiring — gauges, fuses and schematic

Cable gauge formula

S (mm²) = (I × L × 2) ÷ (ΔV × 56)

ΔV = max voltage drop 3% of 12V = 0.36V. 56 = copper conductivity at 20°C.

Run	Current	Min. gauge	Fuse	Note
Panel → MPPT	12A/panel	4 mm² solar	No (MPPT protects)	Double insulation
MPPT → Battery	30–50A	10 mm²	60A fuse, battery side	As short as possible
Battery → Breaker	100A max	25 mm²	100A fuse (ANL)	Within 30 cm
Distrib. → 12V fridge	10A	2,5 mm²	15A fuse	Direct cable
Distrib. → lighting	4A	1,5 mm²	5A fuse	Can be shared

Never skip the ANL fuse on the battery side. It must be within 30 cm of the terminals. It's the only protection against fire in case of a short circuit.

6. Realistic 2026 budget — 3 configurations

Item	Weekend (200Wc)	Full-time (400Wc)	Pro (600Wc)
Solar panels	€320 (2×100Wc flex)	€580 (2×200Wc rigid)	€820 (3×200Wc rigid)
LiFePO4 battery	€280 (100Ah)	€520 (200Ah)	€750 (300Ah)
MPPT controller	€85 (Renogy 30A)	€145 (Victron 40A)	€180 (Victron 50A)
12V/230V inverter	€65 (300W)	€180 (1000W)	€320 (2000W)
Wiring + fuses	€60	€95	€140
Accessories	€40	€60	€80
TOTAL	€850	€1 580	€2 290

7. The 7 mistakes that ruin an installation

Undersizing your needs by 2×

You "estimate" 400 Wh/day, the reality is 900 Wh. Measure with a power meter for 3 days.

✓ Fix: A meter like the Shelly 1PM on each circuit for 72h

Buying a kit with a PWM controller

€299 kits include a PWM. You lose 20-30% of your energy immediately.

✓ Fix: Buy each component separately — MPPT Victron or Renogy

Undersized cables (fire risk)

A 2.5 mm² cable on 30A heats to 90°C+. In a van, that's a fire starting.

✓ Fix: Compute each gauge: S = (I × L × 2) ÷ (ΔV × 56)

Forgetting the ANL fuse on the battery side

Without an ANL fuse within 30 cm of the battery, a short circuit = your van in flames.

✓ Fix: Always an ANL 100A fuse on the main positive cable

Flexible panels glued with no air gap

Direct glue → 85°C → efficiency -10%, lifespan halved.

✓ Fix: Spacer rails of 20mm minimum or ventilated rigid panels

Setting the MPPT to AGM instead of LiFePO4

AGM profile = permanent undercharge. You only use 80% of the capacity.

✓ Fix: Li-Ion profile, absorption voltage 14.6V, float 13.6V

No real-time monitoring

Without a shunt like the Victron BMV-712, the battery shuts off by surprise.

✓ Fix: Victron BMV-712 (€85) or an integrated Smart BMS shunt

Key takeaways

Sizing: Wc = (Wh/day × 1.25) ÷ PSH. A full-time van consumes 965–1 465 Wh/day, i.e. ~400 Wc as standard.
Always favour an MPPT over a PWM: on a 200 Wc panel, the MPPT delivers 194 W effective vs 150 W on PWM, i.e. +29%.
LiFePO4 battery: 10× more cycles, 50% lighter and 100% usable capacity (DoD 0.8) vs 50% for AGM.
Wiring safety: an ANL fuse within 30 cm of the battery terminals is the only protection against fire in case of a short circuit.
2026 budget by use: ~€850 for weekend (200 Wc), €1 580 for full-time (400 Wc), €2 290 for a pro config (600 Wc).

Frequently asked questions

How many solar panels for a camper van?

For a van with a 12V fridge, LED lighting, a laptop and chargers, a 200 to 400 Wc system is standard. In France, 200 Wc generates around 800 Wh/day in summer (south) and 400 Wh/day in winter (north). Work out your real needs: total Wh/day divided by the peak sun hours of your area (3 to 5h per PVGIS).

Flexible or rigid panel for a van?

Rigid panels (tempered glass) offer better efficiency (22-23% vs 18-21%) and a longer lifespan (25 years vs 10-15 years). Flexible ones fit curved roofs and weigh 60% less. For a full-time van, rigid panels with ventilated mounting are recommended if the roof allows it.

MPPT or PWM for a van?

Always MPPT for a permanent van installation. An MPPT controller recovers 10 to 30% more energy than a PWM, especially on cloudy mornings and in winter. The extra cost (€50-100) is paid back within a few months. The Victron SmartSolar MPPT is the market reference.

What cable gauge for van solar panels?

Use the formula: S (mm²) = (I × L × 2) / (ΔV × 56). For 20A over 4m of cable with a max 3% voltage drop on 12V (0.36V): S = (20 × 4 × 2) / (0.36 × 56) = 7.9 mm². Pick 10 mm². Between panels and MPPT: 4mm² solar cable minimum with MC4 connectors.

What budget for a complete van solar installation?

Realistic budget for a 400 Wc / 200Ah LiFePO4 system: rigid 400Wc panels (€400-600), 200Ah LiFePO4 battery (€450-650), Victron 40A MPPT controller (€120-180), cables + fuses + connectors (€80-120). Total: €1 050 to €1 550.

Sources

JRC PVGIS — Solar production calculator ADEME — Photovoltaic guide Victron Energy — SmartSolar MPPT documentation

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