--- In [email protected], James Cook <oldfo...@...> wrote: > > One of the most important things to remember is to make sure that the > panel is mounted on an adjustable frame so as to maximise the 'impact' > of the sun's rays. Some have calculated that laying the panel flat > reduces the output, which is NEVER that great, by as much as 60%. The > lumpy water boys and girls are finding this out to there cost as many > blue sea sailors have bought the very costly stick on, flexible panels > and are very disappointed. > > Jim >
Whilst the general thrust of this is true its a bit over the top for a typical "holiday/weekend boat". The more complex the mounts the more weak spots so making it easier to steal. The loss of efficiency will be more in winter than in summer when mounted horizontally - thats why my panel is a 60 watt one and not something smaller. All it means is that a larger panel will be needed for the same output if mounted horizontally. When you start looking at flexible panel prices you may well find another reason why people find they do not do what they expected - like they bought one that was not large enough to give the required output when mounted horizontally. Another problem is that these are often mounted across curved doghouse roofs. This leaves part in the shade early & late in the day and during the winter and some older panels do not contain internal diodes so they still work to a degree when part is in shade. There are also two or three panel technologies and the older types are not as efficient as the newer ones. Mounting horizontally will be fine as long as you allow for the loss of efficiency and thus choose a larger panel. Tony Brooks PS I find the typical loss of output on my horizontal a bit less than 20% or 1 amp during high summer. and 40% or 2 amps during the winter.
