Solar Modules for Homes and Properties
This article shows how to know power output from solar modules for homes and properties. It shows how to optimise it for winter or summer.
Top quality solar modules catch 18% to 20% of the solar energy available. This is typically 140 watts-180 watts per square metre in full sun from about 10 am to 2 pm. Input tapers off before and after. Such modules are priced accordingly. Buy only top quality unless you have ample space for those cheaper but less efficient.
Solar modules for homes and properties – which way to face?
For maximum daily input, solar modules should face directly into the sun at mid-day: due North or due South. This is not always feasible, but the loss is not appreciable. Even if facing away from the sun at midday, you will still have worthwhile input. If in such situations (and you have room) simply add more solar modules. Their cost now is so low it will not cost much more.
Solar modules for homes and properties – at what vertical angle?
Most books and articles advise to tilt them at the same angle as your latitude (e.g about 33 degrees for Sydney, Australia). Errors of 10 or so degrees, however, make little difference in the yearly total. It is possible to increase winter input (at the expense of summer input) by tilting the modules more upright. Likewise, increasing summer input by having them closer to flat. At one time some people had them adjustable – but this is rarely feasible (or safe) if roof-mounted. But here again, if space is available, simply add solar capacity. This may require a larger solar regulator – it cannot ‘overload’ the existing regulator but it blocks current input in excess of its maximum rating.
Solar modules – shadowing losses
Another issue with solar modules for homes and properties is a loss of input when your solar modules are shadowed. Some loss is inevitable. The losses, however, with up-market modules is far less. Attempts to save money by buying cheap solar modules is counter-productive. There are also solar modules that each has a mini-inverter. With these, shadowing losses are reduced.
Solar modules for homes and properties – solar module types
There are two main types of solar modules for homes and properties: polycrystalline and monocrystalline. Until recently the latter produced more per square metre and priced accordingly. The best polycrystalline solar modules are now (2020) of similar efficiency and price. This is not an area in which to seek bargains. By and large, you pay dollars per actual watt. Not marketing watts!
Solar modules – the capacity you need
The minimum capacity you need varies according to your energy usage, your location and the time of year. See our article How much solar energy available?