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 (stern arch, pushpit, foredeck).
- Sizing rule of thumb: 1 Wp of panel per 1 Ah of raw lithium bank. 200 Ah lithium = 200 Wp minimum, 400 Ah lithium = 400 Wp minimum. Double if offshore cruising without daily engine charging.
- MPPT controller mandatory: never use PWM in 2026, efficiency loss 25-30%. Victron SmartSolar MPPT 100/30 (~ 140 € HT) up to 400 Wp, 100/50 or 150/100 for large banks.
- Typical ROI: 200 Wp sailboat summer cruise = production ~ 80-100 Ah/day in June-August. Savings on generator or marina shore power = payback 4-6 years.
- Full budget 40ft sailboat: 200 Wp rigid + MPPT + installed wiring = ~ 1 200-1 600 € HT. 400 Wp flexible bimini = ~ 2 500-3 200 € HT.
Solar has become the #1 renewable energy source for recreational boating. Simpler than a wind generator, more effective than a hydrogenerator at anchor, quieter than a genset. But choosing between flexible and rigid impacts efficiency, durability, and the boat’s aesthetics.
This article distinguishes the two families, presents the brands distributed by Skysat, and provides a workshop verdict per 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 boating reference, 140 W = ~ 200-280 € HT), BlueSun (Asia, mid-range), Solara (Germany, marine premium).
Flexible panels — technical details
- 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.
- Required area: ~ 1.3 m² for 200 Wp Solbian.
Rigid panels — technical details
- Advantages: maximum efficiency, lifespan 20-25 years, mechanical robustness, lowest cost per Wp.
- Limitations: flat surface required (stern arch, pushpit, foredeck), weight 8-12 kg/m², higher windage underway, less discreet aesthetics.
- Required area: ~ 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) using two technologies:
- PWM (Pulse Width Modulation): outdated, simple, efficiency 70-75%. Unacceptable in 2026.
- MPPT (Maximum Power Point Tracking): modern, efficiency 95-98%. Bonus: automatically adjusts to optimal voltage based on irradiance.
Skysat distributes MPPT only. Reference: SmartSolar MPPT 100/30 (~ 140 € HT) up to 400 Wp, 100/15 (~ 84 € HT) for small installs ≤ 200 Wp.
Sizing based on lithium bank
Rule of thumb: 1 Wp panel per 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 per 0.5 Ah).
2026 model comparison chart
| Model | Type | Power | Area | Price HT |
|---|---|---|---|---|
| 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
- Properly sized wiring: 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 enclose in a closed 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 stern arch
2024 refit: 1 × Victron 140W + 1 × BlueSun 60W mounted on stainless stern arch + MPPT 100/30. Measured output June-August: 90-100 Ah/day Mediterranean, 70-80 Ah/day Atlantic. Total install: 1 350 € HT.
Case 2 — Lagoon 42 catamaran, 400 Wp flexible bimini
2 × Solbian 200W flexible panels on fixed bimini + MPPT 100/30 + Cerbo GX integration. Installation time 6 h workshop (bimini frame + wiring). Summer production 180-200 Ah/day. Total install: 2 800 € HT.
Case 3 — IMOCA racing 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 € HT.
FAQ — Practical solar for sailboats
How many Wp are really needed?
Rule: 1 Wp / 1 Ah raw lithium bank. 200 Ah bank = 200 Wp minimum. Double for offshore without daily engine charging. No need for more unless high consumption like AC or watermaker.
Solar in winter layup?
Yes, useful to maintain lithium bank charge without intervention. 100 Wp rigid + MPPT is enough to offset BMS self-discharge over 6 months.
Portable folding panels?
Good as occasional backup (stopover, solo anchoring) but not for permanent use. 60-100 Wp folding panel + EcoFlow case ~ 250-400 € HT, useful as backup.
Is solar enough offshore?
In trade wind transatlantic (15-25 knots, near-permanent sun), 400 Wp + 200 Ah bank = total autonomy possible without engine. In polar transat, no — hydrogenerator or wind generator needed.
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 boating).
Skysat distributes Victron Energy and BlueSun. Solbian and Sunbeam available on special order. 2026 HT prices are indicative distributor prices.
