Solar Powered Signs
Nexus Alpha Low Power Systems current offers three different styles of solar powered sign:
It has been calculated that every year 5,500,000,000,000,000,000,000,000 joules of energy reach the earth from the sun. That's a lot.
Experience however, is often that whilst the sun may be "up there somewhere", and as hot as ever, somehow down at ground level it's wet and cold. Or of course, dark.
That, in a nutshell, is the problem with solar power. At ground level it is available a lot less often that we might like. And despite that fact that we all know this, quite often people's expectations of solar fly in the face of experience.
The reality of solar is that if you place a 50W panel in the perfect position and in perfect sunshine it will produce 50W of power. Sadly in the UK we rarely get perfect sunshine and in real life it is frequently impossible to put a panel of any size in the best possible position - reality gets in the way. Add to that the unavoidable fact that in winter not only are the days dull but they are also short and it is easy to see that a nominal 50 Watt panel will deliver nothing like that amount of power in real life. But it’s not all bad news! Even in winter you get useful scatter from the sky - you don't actually need line of sight. But you do need to take all of this into account when designing a useful solar system.
So the calculations required are very different from those used to maximise the advantages of solar for, say, water heating. If you can use everything you can get, a pure maximum is all you are after. But for a solar powered sign you must cater for are these depths of winter - knowing that maybe 90% of the available energy is going to be wasted in summer.
Of course as to get closer to the equator such matters become far less of a problem, but in Northern Europe they are a very signficant issue.
Thus, for any solar powered system to work reliably all year round, the reality is that a solar panel has to be over-specified.
NALPS systems can be fitted with wind generators as well - our preferred type being the vertical axis units illustrated as these are intrinsically more robust: they are harder to damage and cannot over-speed (they’re used by the British Antarctic Survey so come with a good pedigree).
The problem with wind is it is highly unpredictable and, sadly, you can’t even bet on it being there when the sun is absent. But in some regions it can certainly help out.