Grid Connected Solar Power System

In a nutshell, grid tied systems are for generating revenue by selling excess solar power back to the grid for money or credits.

Grid tied systems do not have a battery storage system as they simply pump excess power back onto the grid.

Off-grid systems are designed to operate more like a backup generator. They store solar power and allow the user to utilize that stored power during other times of the day when the sun is not present.

That being said, you can make a hybrid system that functions like a grid tied system, but also has a battery pack for those moments the grid goes down.

Sizing the battery pack is not a simple thing to do. You must first understand your periodic energy needs (usually in kilo Watts) and you must also know the duration of the down time you want the battery backup system to run.

Also, you should size the battery system so that it never drains the battery more than 50%. Actually, 75% is better as the more you drain the battery, the shorter the life of the batteries.

So, when sizing the battery pack you must also contend with expected battery replacement life and its costs.

As Lyn stated, you need to do a lot of research as the subject is a bit complex.

I really like MJ Lorton's videos on the subject for those that are just getting into solar power. They are a little long, but he does a good job explaining things.

MJ Lorton Solar DIY