Just 3.5mm thin our weather proof panels are tough enough to withstand being stepped on when wearing soft soled shoes
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.
The panels can be gently flexed (in one dimension.) to follow a smooth curve, such as a coach roof, by up to 2.5cm per 100cm of panel length. Four, grommet finished, holes are provided for screw fixing. Alternatively panels can be glued into position using mastic. The panels do not contain glass and, when correctly mounted, can be stepped upon when wearing soft soled shoes.
A sealed junction box is fitted with 2.5m of output cable, a connector and fuse protected crocodile clips. Electrical connection is simple though the use of a solar regulator is recommended to prevent overcharge if the system is to be left unattended for long periods or the solar panel to battery ratio exceeds the minimum of 10W to 100Ah. An internal blocking diode prevents reverse current drain at night. The panel is protected with an inline 3 Amp fuse.
FITTING THE PANEL
Selecting a suitable position for a solar panel will always be a trade off between finding a surface where it won't suffer mechanical damage and finding a position where it will receive maximum sunlight uninterrupted by shadows from sails, masts etc.
Once a suitable position has been identified the panel can be attached using screws passing through the four grommets. (Do not remove these grommets.) The panel can be slightly flexed to follow the surface contour. However that flexing MUST NOT EXCEED 2.5cm for every 100cm of length. (For example if a 50cm solar panel is fixed down at one end then the other end must not be flexed down more than 1.25cm.) Alternatively the panel can be glued into position using mastic.
Using a suitable deck gland the output cable can be run back to the battery. Ensure that the cable entry to the panel is not subject to excessive strain. Plug the connector into the crocodile lead assembly and attach the red clip to the battery positive and the black clip to negative. (If used in conjunction with a BM1 battery monitor then connect the red lead to the positive of the service battery and the black lead to the load/generator end of the shunt.) Take care not to connect the the leads the wrong way round. Where the solar panel does not exceed 10 watts per hundred amp hour of battery capacity it is generally accepted that a charge controller is unnecessary. For higher solar panel to battery ratios a charge controller may be advisable particularly in the unlikely event of the UK having a long hot summer.
The 20 watt panel measures 360mm x 505mm