Rule 1 - Never ever cheat when calculating solar requirements The saving will be short lived!
We all like to save a dollar but the reality is that when it comes to solar power you are better off spending the extra dollar. That extra you spend becomes insurance - it ensures you have petrol in the tank on a rainy day. Calculate your requirements and then buy the next size up. Rule 2 - Design your system to suit your enviroment.
Every installation is different in terms of where and what. The "where" is simple. The Northern Territory and Tasmania are just a little different when calculating solar requirements. In Australia we work on an average year round of five hours of sunlight per day. Now whilst that is a very convenient figure the reality is that it is an average and the NT is going to get a lot more than that and Victoria will probably not. So a little bit of common sense comes into play. The people in Victoria up the ante.
The "what" means you need to consider how open or shaded the site is. Solar panels are made up of a series of cells connected in series and if you shade even a small corner the entire solar panel is dead. It is like a bike chain - you only need one link to break and the whole thing is useless. What this means is if you have tree, buildings etc. anywhere near the solar panel mounting point we need to allow for the fact that we will not get our Australian average five hours. We need to collect our energy in a shorter period of time so we need a bigger panel.
You are not left alone to work it all out. Give your local branch a call and request some help or email the service department.