Solar panels for boats: flexible or rigid? SUNBEAM, Solbian and Victron compared

There are two kinds of solar panel for a boat: flexible panels that you glue onto the deck or bimini, and rigid glass panels with an aluminium frame. Flexible marine panels from SUNBEAM cost from €289 for 55 watts and weigh just over a kilo; rigid panels from Victron are much heavier but come with a 25-year power warranty. Neither will drive an electric motor; they top up the battery.

SUNBEAM, Solbian and Victron compared

\* Victron price list "EUR C" excluding VAT; the list does not make clear whether these are retail prices, and panels have a minimum order of 4 to 5 units. SUNBEAM does not state clearly whether VAT is included. None of the three manufacturers publishes prices in GBP.

Sources: SUNBEAM Tough G8 55 W, 78 W, 114 W, Solbian SP series, Solbian SR series, Solbian warranty, Victron BlueSolar, Victron price list.

Flexible or rigid: which suits your boat?

Flexible panels weigh a fraction per watt: the 114 W SUNBEAM panel weighs 2.6 kg, the rigid 130 W Victron panel 7.1 kg. They lie flat on the deck, cabin roof or bimini and hardly get in the way. Solbian calls its panels walk-on, but the SP series only when bonded across its full area to a solid surface, and the SR series when professionally bonded (Solbian SP, SR). Solbian has had its panels tested for salt mist to IEC 61701; SUNBEAM describes its panels as designed for demanding marine conditions, without naming a standard.

Rigid panels are heavier and need a spot where they are out of the way, such as an arch at the stern. In return, Victron is the only manufacturer here to give a long power warranty: 90% of output after 10 years, 80% after 25 years. Solbian guarantees 80% for 5 years; SUNBEAM gives 5 years with no power commitment.

Efficiency figures are not directly comparable: Victron states the efficiency of the whole panel at 17 to 19%, Solbian and SUNBEAM that of the cells at 22.5 to 24.4%. Both flexible manufacturers use monocrystalline cells, Solbian's SP series and SUNBEAM cells from Maxeon/SunPower.

Where to buy?

SUNBEAM from Sweden lists dealers in the UK (including Chris Rothwell Marine Electrics, Ocean Chandlery, Marine Superstore and Hamble Chandlery), the Netherlands and Germany; Austria and Switzerland are served only by its own online shop (SUNBEAM dealers). For Solbian we found no official distribution in the UK or Germany; the website only gives an email address for its sales network and no prices (Solbian). Victron sells through dealers; the dealer finder on its website only works with a location search (Victron).

Which charge controller do you need?

A charge controller sits between panel and battery. Victron offers the SmartSolar MPPT for this, for example the 75/15 (up to 75 V input voltage, 15 A charge current), 100/20 and 100/30 (Victron MPPT 75/15 and 100/20, 100/30). According to the price list they cost €68, €96 and €137 excluding VAT, with the same caveat as for the panels. Which battery suits them is covered in Lithium boat battery: Victron and ECTIVE compared.

How much power does a solar panel deliver on a boat?

None of the three manufacturers gives a yield figure in watt-hours per day. The rated power only applies under laboratory conditions in full sun. For comparison, by our calculation: under those conditions a 114-watt panel delivers about one ninth of what a 1 kW outboard draws at full throttle. That is not enough to drive the boat, but it is enough to top up the battery at the mooring or to run lights, a fish finder and a cool box. Boats that cover their entire roof with solar are compared in Solar boats: PEHN, PonTOM, Silent Yachts and Sunreef.