This article by Collyn Rivers outlines the solar basics you need to know to ensure your self-built solar works first time and every time – at minimal cost.
Solar Basics You Need to Know – is there enough sun?
Generalising, solar is feasible in most parts of the world between latitudes +/- 50 degrees. Solar input is typically quoted in PSH (Peak Sun Hours) per day. Google PSH and your closest town and you are likely to have the answer. If not, however, contact your local met office.
In most areas, PSH varies with time of year. That need is at least 2.5 PSH/day, but 3.0 PSH is preferable. The minimum PSH determines the solar module capacity required. You then check there is non-shadowed space for that capacity.
The solar modules must face more or less north (in the southern hemisphere). More or less south (in the northern hemisphere). For optimum year-round input, they should be tilted at (your) latitude angle. You can, however, tilt than more upright to increase winter input. Or less steeply for summer. Between 0 and 20 degrees north or south of the equator, however, they can be almost horizontal year-round.
Solar Basics You Need to Know – how much solar capacity do I need?
Most solar suppliers check your current usage – or use locally known averages. This, to put mildly, is not the way to go.
Your first step is to do all you can to minimise usage. This is not simple. Over a third of my book, Solar Success is devoted to just this. It shows how to (typically) slash usage by at least one third. Half is readily possible. Doing so will save you thousands of dollars in solar and (particularly) ongoing battery costs.
From there, you design the system to provide whatever percentage of the energy needed. It is possible to have 100% but settling for 95% will halve the cost!
Solar Basics You Need to Know – battery and generator back-up
Stand-alone solar systems typically have battery storage for two to three days of zero solar input. A generator and a large battery charger then recharges the system. Battery storage is however costly and can be reduced if the generator is used more often.
Solar Basics You Need to Know – ongoing maintenance
Apart from cleaning the solar modules if they get dusty or muddy – they need no other attention. Their useful life-span in 25-30 years. The batteries now used are usually maintenance free. Battery lifespan is typically 12-16 years.
Solar Basics You Need to Know – can I build the system myself?
Many do but it does need some electrical experience. Unless you have, Solar Books advises seeking assistance. Much of the work, however, is mechanical. Framework for solar arrays is readily buyable. Huge savings can be made by constructing these yourself but you must allow for wind forces etc. Solar Success, however, shows that required. (It was built to withstand cyclones but is still far cheaper than standard commercial equivalents).
We strongly advise buying Solar That Really Works! (for boats, cabins and RVs). Buy Solar Success for homes and properties. Our book Caravan & Motorhome Electrics covers every aspect of that topic. All are routinely updated. Their content is globally valid.
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