Recommended Project Tools
Here are some great tool links from the creator of my favorite DIY Solar/PV Energy guide, The Solar Electricity Handbook, by Michael Boxwell.
These solar calculator applications seem to be the most practical and comprehensive on the web as far as my research has gone. I've used these tools extensively.
The Off-Grid Solar Project Analysis produces a 10-page report on your project, working out the size of panels required, the right angle to position them; the best batteries to use - and VERY IMPORTANTLY - the right thickness of cables you'll need for your project.
The grid-tie solar calculator produces a report that will allow you work out how many solar panels you will need to create a theoretical 'carbon neutral' building. You will need to work with your local planning department, and certified electrician to undertake a grid-tie project.
I love their online solar angle calculator and solar irradiance tables. They literally cover every country in the world.
Soon to come, our components resource section will help you find the right photovoltaic equipment for your project, and for builds we've put together ourselves.
More info at Michael's site, solarelectricityhandbook.com