A solar panel can provide a near maintenance free solution to keeping batteries charged when unattended. An occasional wipe with a damp cloth is all that is necessary to ensure the panel continues to trickle energy into the battery. Keeping the battery topped up will improve its reliability and can extend its useful working life. Whilst solar panels give their maximum output in direct sunlight, even an overcast day can provide a useful level of charge.
The Nasa marine 12 volt, semi flexible solar panels are robustly constructed on a fibre glass substrate and are protected by a scratch proof transparent Tedlar polymer. Only 3.5mm thick and lightweight, they have no metal outer components to make contact with the surface to which they are fitted. The efficient and stable polycrystalline cells are encapsulated between two tough outer layers so the whole panel is weatherproof and carries a limited one year warranty.