The essentials in 30 seconds
- Flexible vs rigid: flexible (Solbian, Sunbeam, Renogy) = adaptable bimini/hood/curved deck, -10 to -15% efficiency vs rigid, 8-12 year lifespan. Rigid (Victron 140W, BlueSun) = maximum efficiency, 20-25 year lifespan, 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, 25-30% efficiency loss. Victron SmartSolar MPPT 100/30 (~ $150 USD) up to 400 Wp, 100/50 or 150/100 for large banks.
- Typical ROI: 200 Wp sailboat summer cruising = ~80-100 Ah/day production in June-August. Savings on generator or shore power = payback 4-6 years.
- Complete budget 40-foot sailboat: 200 Wp rigid + MPPT + wiring installed = ~ $1,300-$1,750 USD. 400 Wp flexible bimini = ~ $2,700-$3,500 USD.
Solar has become the #1 renewable energy source for recreational boating. Simpler than a wind turbine, more efficient 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 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 = ~ $220-$300 USD), BlueSun (Asia, mid-range), Solara (Germany, premium marine).
Flexible panels — technical details
- Pros: adaptable to bimini/hood/curved deck, lightweight (2-4 kg/m²), low windage, discreet aesthetics.
- Cons: -10 to -15% efficiency vs rigid at equivalent power, 8-12 year lifespan (polymer film degrades), irreparable if punctured.
- Area required: ~1.3 m² for 200 Wp Solbian.
Rigid panels — technical details
- Pros: maximum efficiency, 20-25 year lifespan, mechanical robustness, lowest $/Wp.
- Cons: flat surface required (stern arch, pushpit, foredeck), 8-12 kg/m² weight, high 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) using two technologies:
- PWM (Pulse Width Modulation): outdated, 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 (~ $150 USD) up to 400 Wp, 100/15 (~ $90 USD) for small installs ≤ 200 Wp.
Sizing by 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 USD |
|---|---|---|---|---|
| Victron 140W | Rigid mono | 140 Wp | 1.25 × 0.67 m | ~ $300 |
| Solbian SP 144Q | Flexible mono | 144 Wp | 1.40 × 0.70 m | ~ $1,020 |
| Sunbeam Tough 160W | Flexible mono | 160 Wp | 1.40 × 0.80 m | ~ $780 |
| BlueSun 200W rigid | Rigid mono | 200 Wp | 1.55 × 0.80 m | ~ $240 |
| Victron MPPT 100/30 | Controller | 400 Wp max | — | ~ $150 |
Practical installation on a sailboat
Skysat workshop rules
- Proper wire sizing: 200 Wp at 12 V = 17 A nominal → 4 mm² minimum cable, 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 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 production June-August: 90-100 Ah/day Mediterranean, 70-80 Ah/day Atlantic. Total install: $1,450 USD.
Case 2 — Lagoon 42 catamaran, 400 Wp flexible bimini
2 × Solbian 200W flexible panels on fixed bimini + MPPT 100/30 + Cerbo GX integration. 6-hour workshop install (bimini cover + wiring). Summer production 180-200 Ah/day. Total install: $3,000 USD.
Case 3 — IMOCA racing sailboat, 600 Wp semi-rigid
3 × custom semi-rigid 200W panels each + 2 × MPPT 150/45 dual-zone. Offshore production 250-300 Ah/day. Material cost ~ $4,850 USD.
FAQ — Sailboat solar in practice
How many Wp do I really need?
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 air conditioning/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 foldable panels?
Good as occasional backup (stopover, solo anchoring) but not for permanent use. 60-100 Wp foldable + EcoFlow case ~ $270-$430 USD, useful as backup.
Is solar enough offshore?
In trade wind transatlantic (15-25 knots, near-permanent sun), 400 Wp + 200 Ah bank = possible full autonomy without engine. In polar transat, no — hydrogenerator or wind turbine 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 craft).
Skysat distributes Victron Energy and BlueSun. Solbian and Sunbeam available on special order. 2026 USD prices are indicative distributor prices.
