The essentials in 30 seconds
- Flexible vs rigid: flexible (Solbian, Sunbeam, Renogy) = adaptable bimini/awning/curved deck, efficiency -10 to -15% vs rigid, lifespan 8-12 years. Rigid (Victron 140W, BlueSun) = maximum efficiency, lifespan 20-25 years, requires flat surface (aft arch, stern pole, foredeck).
- Sizing rule of thumb: 1 Wp of panel for 1 Ah of raw lithium bank. 200 Ah lithium = 200 Wp minimum, 400 Ah lithium = 400 Wp minimum. Double for offshore cruising without daily engine charging.
- MPPT controller mandatory: never use PWM in 2026, 25-30% efficiency loss. Victron SmartSolar MPPT 100/30 (~ 140 € ex VAT) up to 400 Wp, 100/50 or 150/100 for large banks.
- Typical ROI: 200 Wp sailboat summer cruising = production ~ 80-100 Ah/day in June-August. Savings on generator or marina charging = payback 4-6 years.
- Complete budget 40-foot sailboat: 200 Wp rigid + MPPT + wiring installed = ~ 1,200-1,600 € ex VAT. 400 Wp flexible bimini = ~ 2,500-3,200 € ex VAT.
Solar has become the #1 renewable energy source for recreational boating. Simpler than a wind generator, more efficient than a hydrogenerator at anchor, quieter than a genset. But the choice between flexible and rigid impacts efficiency, durability, and aesthetics.
This article distinguishes the two families, presents the brands distributed by Skysat, and gives a workshop verdict by program. For battery bank sizing, see our sizing method article.
The two families — flexible vs rigid
Flexible
Photovoltaic cells under sealed polymer film, up to 30° curvature possible. Brands: Solbian (Italy, premium, ~ 6-9 €/Wp), Sunbeam (Germany, mid-range, ~ 4-6 €/Wp), Renogy (China/USA, entry-level, ~ 2-4 €/Wp).
Rigid
Monocrystalline cells under tempered glass + aluminum frame. Brands: Victron (pleasure craft reference, 140 W = ~ 200-280 € ex VAT), BlueSun (Asia, mid-range), Solara (Germany, premium marine).
Flexible panels — technical detail
- Advantages: adaptable to bimini/awning/curved deck, lightweight (2-4 kg/m²), low windage, discreet aesthetics.
- Limitations: efficiency -10 to -15% vs rigid at equivalent power, lifespan 8-12 years (polymer film degrades), irreparable if punctured.
- Area required: ~ 1.3 m² for 200 Wp Solbian.
Rigid panels — technical detail
- Advantages: maximum efficiency, lifespan 20-25 years, mechanical robustness, lowest €/Wp.
- Limitations: flat surface required (aft arch, stern pole, foredeck), weight 8-12 kg/m², higher windage underway, less discreet aesthetics.
- Area required: ~ 1.1 m² for 200 Wp Victron.
MPPT controller — why it's mandatory
The charge controller converts panel voltage (variable 14-22 V to 12 V bank) with two technologies:
- PWM (Pulse Width Modulation): legacy, simple, 70-75% efficiency. Unacceptable in 2026.
- MPPT (Maximum Power Point Tracking): modern, 95-98% efficiency. Bonus: automatically adjusts to optimal voltage based on irradiance.
Skysat distributes MPPT only. Reference: SmartSolar MPPT 100/30 (~ 140 € ex VAT) up to 400 Wp, 100/15 (~ 84 € ex VAT) for small installs ≤ 200 Wp.
Sizing by lithium bank
Rule of thumb: 1 Wp panel for 1 Ah raw lithium bank.
- 100 Ah lithium bank → 100 Wp minimum.
- 200 Ah lithium bank → 200 Wp minimum.
- 400 Ah lithium bank → 400 Wp minimum.
- Offshore without daily engine charging → double (1 Wp for 0.5 Ah).
2026 model comparison chart
| Model | Type | Power | Area | Price ex VAT |
|---|---|---|---|---|
| Victron 140W | Rigid mono | 140 Wp | 1.25 × 0.67 m | ~ 280 € |
| Solbian SP 144Q | Flexible mono | 144 Wp | 1.40 × 0.70 m | ~ 950 € |
| Sunbeam Tough 160W | Flexible mono | 160 Wp | 1.40 × 0.80 m | ~ 720 € |
| BlueSun 200W rigid | Rigid mono | 200 Wp | 1.55 × 0.80 m | ~ 220 € |
| Victron MPPT 100/30 | Controller | 400 Wp max | — | ~ 140 € |
Practical installation on sailboat
Skysat workshop rules
- Wiring gauge sized: 200 Wp at 12 V = 17 A nominal → 4 mm² cable minimum, length ≤ 5 m.
- Series fuse on panel output: 25 A for 200 Wp, 50 A for 400 Wp.
- Blocking diode: integrated in modern panels. Check datasheet.
- MPPT ventilation: dissipates 10-15 W at full load, do not install in enclosed cabinet.
- VictronConnect MPPT programming: lithium LFP profile, absorption 14.4 V, float 13.5 V.
3 real-world workshop cases
Case 1 — Bénéteau Oceanis 40, 200 Wp rigid on aft arch
2024 refit: 1 × Victron 140W + 1 × BlueSun 60W mounted on stainless steel aft arch + MPPT 100/30. Measured output June-August: 90-100 Ah/day Mediterranean, 70-80 Ah/day Atlantic. Total install: 1,350 € ex VAT.
Case 2 — Lagoon 42 catamaran, 400 Wp flexible on bimini
2 × Solbian 200W flexible panels on fixed bimini + MPPT 100/30 + Cerbo GX integration. 6-hour workshop install (bimini frame + wiring). Summer production 180-200 Ah/day. Total install: 2,800 € ex VAT.
Case 3 — IMOCA race sailboat, 600 Wp semi-rigid
3 × custom 200W semi-rigid panels each + 2 × MPPT 150/45 dual-zone. Offshore production 250-300 Ah/day. Material cost ~ 4,500 € ex VAT.
FAQ — Solar on sailboats in practice
How many Wp do I really need?
Rule: 1 Wp / 1 Ah raw lithium bank. 200 Ah bank = 200 Wp minimum. Double for offshore without daily engine charging. More only useful for high loads like air conditioning or watermaker.
Solar in winter lay-up?
Yes, useful to maintain lithium bank charge without intervention. 100 Wp rigid + MPPT is enough to offset BMS self-discharge over 6 months.
Portable foldable panels?
Good as occasional backup (stopover, solo anchoring) but not for permanent use. 60-100 Wp foldable + EcoFlow case ~ 250-400 € ex VAT, useful as backup.
Is solar enough offshore?
In tradewind transatlantic (15-25 knots sun almost constant), 400 Wp + 200 Ah bank = full autonomy possible without engine. In polar transat, no — hydrogenerator or wind generator required.
Which MPPT for which bank?
MPPT 100/15 up to 200 Wp. MPPT 100/30 up to 400 Wp. MPPT 150/45 up to 600 Wp. MPPT 250/100 up to 1200 Wp (rarely needed in pleasure craft).
Skysat distributes Victron Energy and BlueSun. Solbian and Sunbeam available on special order. 2026 prices ex VAT are indicative distributor pricing.
