SELECTING A SOLAR PANEL FOR YOUR BOAT OR VAN
Some of these things are pretty negative, so we risk talking you out of solar. There are, however, some very positive aspects as well.
Firstly, you MUST understand that solar panel arrays are pretty inefficient. Almost all of them are made from Silicon. At best, a good solar panel will yield about 14% of the energy from the sun into electricity. On a good day, roughly 1kW of energy from the sun falls on every square meter of the earth on average. So that means you get about 140 watts of electricity from a square meter of a good solar panel. Now the bad news.
If its a cloudy day the solar output goes down to as low as 1% conversion. If a shadow falls across any part – even a small part of the solar array, the output plummets to almost nothing. (This is why you should never allow trees to shadow your roof-mount domestic solar installation and you should try to keep them cool.)
So why are they so popular? Domestically, solar power is massively subsidised. If you read the paper, you will see much debate about the merits, or otherwise, of this.
This will not help you unless the government accepts that your boat or caravan is a house!In order for a solar array to be justified, you must consider the alternatives first.
• Will you always have a source of cheap and reliable (i.e. 240V) power handy?
• If not, are there alternatives?
• If yes, what are they?
• Wind power. Really only an option for boats
on moorings. Wind generators exist, they work well but they are expensive.
• Fossil fuel power. Petrol or diesel generators are fairly cheap, powerful, but noisy and expensive to run and will eventually wear out.
Despite all of the above and you need other things to manage them, solar power can still be a good idea. They are very useful if you don’t need A LOT of power.
• Given enough time, they are great for charging batteries or banks of batteries.
• They can run energy efficient things like LED lighting and small LCD TV’s, small pumps, etc.
• With an inverter (see elsewhere in this catalogue) you can operate bigger things (like kettles, refrigerators, etc) for limited amounts of time at night or day.
In conclusion, solar panels are very handy if you adopt the philosophy of energy management and conservation. They free you from a fixed power point and noisy generators. In some ways it does not matter how efficient they are if you have the time to let them do their job. And, given a modest amount of maintenance & care, will do so for at least 20 years.