Before You Buy
There are more than 10 000 different solar brands today. Very few are reliable though.
There are a number of global general standards and certification bodies that are used on solar products. Some standards will depend on your location. Typical standards to look for on solar panels include IEC, TUV and SA certification.
With inverters check for the following IEC, CEC, VDE.Certifications only work as a guide to eliminate obvious operation and integration problems. However this does not guarantee zero failure rate.
The size of your solution largely depends on your requirements, and budget!
For a residential solution the sizing standard is in kW (1000W) relating to the total wattage produced by the panels. An average home of four people will run on 3kW without the use of artificial heating and cooling, which can easily double or quadruple the required size.
Popular panel sizes are 330W, 360W and 400W hence a 3kW system usually comes with 6 to 8 panels.
Batteries come in two basic technologies, Lithium or Lead.
The lead based battery types are tried, tested and predictable. With a lifespan of 3 to 5 years and coming in a simple box these batteries are the easiest to work with. Typical variations include the Gel cell, AGM, Valve Regulated Lead Acid VRLA and the flooded.
The latest technology in batteries is the Lithium ion technology which a group of tiny AA size batteries interconnected to make a large battery. These batteries introduce some advantages absent in Lead based batteries but also come with new product problems; integration, exaggerated perfomance and very high cost.