200W vs 400W vs 600W Solar: What's Right for Your Van?
Choosing the right amount of solar for your campervan is one of the most debated topics in the van build community. Too little and you are constantly worrying about power. Too much and you have spent money and roof space on capacity you never use. The answer depends on what you power, where you travel, and how often you drive.
This guide is part of our complete campervan solar setup guide. We will walk through the three most common system sizes — 200W, 400W, and 600W — with real UK output figures so you can make an informed decision. If you want a precise recommendation based on your actual appliance list, use our free calculator.
Get a personalised solar recommendation
Tell our calculator what you want to power and how you use your van. It recommends the exact solar wattage, battery size, and charge controller you need.
How Much Power Does Each System Actually Produce?
Solar panel ratings are based on laboratory conditions — 1,000 W/m² of irradiance at 25°C cell temperature. In the UK, real-world output is significantly lower due to our latitude, cloud cover, and shorter winter days.
Average Daily Output in the UK
| System Size | Summer (Jun–Aug) | Spring/Autumn | Winter (Dec–Feb) | Annual Average |
|---|---|---|---|---|
| 200W | 700–900 Wh/day | 400–600 Wh/day | 100–250 Wh/day | 450–550 Wh/day |
| 400W | 1,400–1,800 Wh/day | 800–1,200 Wh/day | 200–500 Wh/day | 900–1,100 Wh/day |
| 600W | 2,100–2,700 Wh/day | 1,200–1,800 Wh/day | 300–750 Wh/day | 1,350–1,650 Wh/day |
These figures assume panels are mounted flat on the roof (no tilt), a decent MPPT charge controller, and average UK conditions. Scotland will see lower figures; the south of England slightly higher.
Peak sun hours vary dramatically in the UK
In June, southern England gets roughly 4.5 peak sun hours per day. In December, that drops to around 0.7. This means your 400W system that produces 1,600 Wh in summer might only produce 280 Wh in the depths of winter. Always size your system for the season you plan to use it most.
The 200W System
A 200W system is the entry point for solar on a campervan. It typically consists of a single 200W panel or two 100W panels.
What 200W Can Power
- LED lighting (all evening)
- Phone and tablet charging
- USB devices
- A 12V compressor fridge (in summer, with supplemental charging)
- Small 12V fans
- Occasional laptop charging
What 200W Cannot Comfortably Power
- A compressor fridge year-round without driving or shore power
- An inverter running a coffee machine, toaster, or hair dryer
- Diesel heater for extended periods without driving
- Multiple laptops or monitors for remote working
Best Battery Pairing
A 200W system pairs well with a 100Ah lithium (LiFePO4) battery. This gives you around 1,200 Wh of usable capacity, which the panels can replenish in a good summer day. In winter, you will need to supplement with a DC-DC charger from the alternator.
Cost
| Component | Typical UK Price |
|---|---|
| 200W panel (rigid) | £90–£140 |
| MPPT controller (15–20A) | £60–£120 |
| Mounting hardware | £20–£40 |
| Cabling and glands | £20–£30 |
| Total | £190–£330 |
Who Should Choose 200W?
- Weekend and holiday users who also drive regularly
- Vans with shore power access at campsites
- Minimalist setups without high-draw appliances
- Budget builds where every pound counts
- Small vans with limited roof space (VW Caddy, Berlingo)
The 400W System
A 400W system is the most popular choice for full-time and extended-trip campervans in the UK. It usually consists of two 200W panels or four 100W panels.
What 400W Can Power
- Everything in the 200W list, plus:
- A 12V compressor fridge year-round (with DC-DC charger backup in winter)
- A diesel heater running regularly
- Laptop for daily remote working
- An inverter for occasional 230V appliance use (coffee machine, blender)
- Water pump and USB sockets throughout the van
What 400W Struggles With
- Running a large inverter load for extended periods (kettles, hairdryers, toasters)
- Powering an air conditioning unit
- Winter off-grid stays longer than 2–3 days without driving
- Multiple people each running laptops and devices all day
Best Battery Pairing
A 400W system pairs well with a 200Ah lithium battery, giving 2,400 Wh of usable capacity. This provides two to three days of autonomy for a typical couple's campervan, even with minimal solar input.
Cost
| Component | Typical UK Price |
|---|---|
| 2x 200W panels (rigid) | £180–£280 |
| MPPT controller (30A) | £100–£200 |
| Mounting hardware | £30–£60 |
| Cabling and glands | £30–£50 |
| Total | £340–£590 |
Who Should Choose 400W?
- Full-time or long-trip vanlifers
- Remote workers needing daily laptop power
- Couples who want to wild camp without constant range anxiety
- Vans with a compressor fridge and diesel heater
- Most medium-to-large vans (Ducato, Sprinter, Transit, Crafter)
The 600W System
A 600W system is the premium choice, typically using three 200W panels. It requires a large van roof (Sprinter LWB, Ducato L3H2, or similar) and is aimed at heavy power users or year-round off-grid living.
What 600W Can Power
- Everything in the 400W list, plus:
- Extended inverter use for 230V appliances
- Two people working remotely with laptops and monitors
- An electric cool box and a compressor fridge simultaneously
- Longer winter off-grid stays (3–5 days with good battery capacity)
- Higher continuous loads without worrying about drain
What 600W Still Cannot Do
- Run an air conditioning unit (these need 1,500–3,000W continuous)
- Replace shore power entirely in a UK winter for heavy users
- Power electric cooking appliances (induction hob, oven) for regular use
Best Battery Pairing
A 600W system needs a 300Ah+ lithium battery bank to make the most of its output. With 3,600 Wh of usable capacity, you have genuine multi-day autonomy even in shoulder seasons.
Cost
| Component | Typical UK Price |
|---|---|
| 3x 200W panels (rigid) | £270–£420 |
| MPPT controller (40–50A) | £150–£300 |
| Mounting hardware | £40–£80 |
| Cabling and glands | £40–£60 |
| Total | £500–£860 |
More solar needs a bigger charge controller
If you upgrade from 400W to 600W, check that your charge controller can handle the additional current. A 30A MPPT controller that was fine for 400W will be at its limit with 600W. Undersizing the controller wastes the extra panel capacity. See our guide on solar charge controller sizing for the calculations.
Who Should Choose 600W?
- Full-time vanlifers, especially in the UK year-round
- Digital nomad couples both working from the van
- Heavy power users who dislike compromising
- Large vans with the roof space to accommodate three panels
- Those who want maximum off-grid independence
Head-to-Head Comparison
| Factor | 200W | 400W | 600W |
|---|---|---|---|
| Summer daily output (UK avg) | 800 Wh | 1,600 Wh | 2,400 Wh |
| Winter daily output (UK avg) | 175 Wh | 350 Wh | 525 Wh |
| Ideal battery size | 100Ah | 200Ah | 300Ah+ |
| Roof space needed | ~1.0 m² | ~2.0 m² | ~3.0 m² |
| System cost (panels + controller) | £190–£330 | £340–£590 | £500–£860 |
| Best for | Weekenders | Most vanlifers | Full-timers |
| Compressor fridge (year-round) | With backup | Yes | Yes |
| Remote working | Light use | One person | Two people |
| Winter off-grid (UK) | 1 day | 2–3 days | 3–5 days |
The DC-DC Charger Factor
Do not choose your solar size in isolation. A DC-DC charger that charges from your alternator while driving is an essential complement to solar in the UK, especially in winter.
A typical 30A DC-DC charger puts roughly 360W into your batteries while driving. Over a two-hour drive, that is 720 Wh — equivalent to what 200W of solar produces on a decent summer day. In winter, driving is often your primary charging source.
This means a 200W solar setup paired with a good DC-DC charger and regular driving can match the off-grid capability of a 400W system with minimal driving. Factor your driving habits into the decision.
Roof Space Reality Check
Before choosing a system size, measure your actual available roof space. Remember to account for:
- Roof fans (MaxxFan, Fiamma) — typically 400mm x 400mm
- Skylights or roof windows
- TV aerials or satellite dishes
- Roof rack crossbars
- Air conditioning units (if fitted)
- Clearance around panel edges (50mm minimum recommended)
For a breakdown of how much solar fits on popular UK van models, see our guide on campervan roof space by van model.
Measure twice, order once
Lay out cardboard templates on your roof before ordering panels. Account for the mounting hardware overhang and leave at least 50mm clearance from roof edges and fixtures. Take photos from above — it is easy to misjudge space from the side.
Making Your Decision
If you are still unsure, work through these three steps:
- List your appliances and their daily usage (our calculator does this automatically)
- Check your roof space to see what physically fits
- Consider your charging mix — how much will you drive? Will you use campsites with hook-up?
Most UK vanlifers land on 400W as the sweet spot. It covers the needs of a couple with a fridge, diesel heater, and daily device charging, without requiring the largest van roof. Add a DC-DC charger and you are well covered for three-season use.
If you primarily van in summer and drive regularly, 200W is perfectly adequate. If you are a full-time remote worker or live in your van year-round, 600W gives meaningful extra headroom.
Still unsure? Let the calculator decide
Enter your appliances, travel patterns, and van model. Our free calculator recommends the exact solar wattage for your specific setup — no guesswork needed.
Frequently Asked Questions
Can I start with 200W and add more panels later?
Yes, this is a common approach. Make sure your initial charge controller is rated for the larger system you might build later. For example, buy a 30A MPPT controller now even if your 200W system only needs 15A. Wiring in an additional panel later is straightforward if you plan the roof layout and cable routing in advance.
Does the panel brand matter more than the wattage?
Panel quality affects longevity and real-world output, but the wattage difference between brands for the same rated panel is small (typically within 5%). A 200W panel from Renogy will produce very similar output to a 200W panel from Victron under the same conditions. For a brand comparison, see our Renogy vs Victron solar panel guide.
Is 400W of flexible panels equivalent to 400W of rigid panels?
In theory, yes. In practice, flexible panels run hotter because they lack the air gap that rigid mounted panels benefit from. This can reduce real-world output by 10–15%. Flexible panels also degrade faster. If you have the roof height for rigid panels, they are the better investment.
Should I go series or parallel for my panel configuration?
This depends on your charge controller, cable lengths, and shading conditions. For a detailed comparison, see our guide on solar series vs parallel wiring.
How long do solar panels last on a campervan?
Quality rigid monocrystalline panels are rated for 25+ years, though output degrades slowly over time (roughly 0.5% per year). On a campervan, the practical lifespan is often limited by mounting hardware, sealant maintenance, and physical damage rather than panel degradation.
Is 600W overkill for a solo traveller?
For most solo travellers, yes. A single person typically uses 400–800 Wh per day. A 400W system covers this comfortably in three seasons. The exception is if you are a heavy power user — running a desktop computer, multiple screens, or power tools — in which case 600W gives useful headroom.