Hybrid Solar Power Systems
Hybrid solar is much like Grid connect solar but instead of feeding the excess back to the grid you feed the excess into batteries. Therefore the solar powers your daytime use in the home and any excess gets put into the batteries which to cover your night time use. You are still connected to the grid so if it rains for a week and your solar output is low you can draw from the grid. (this saves having an oversized battery bank that is only occasionally used which therefore saves a lot of extra costs) Whereas in a off grid system you use a generator as back- up. In a hybrid system you would use the grid as backup. Generous government incentives are still applicable to hybrid systems.
The Main types of batteries used are
Tubular gels AGM deep cycle Batteries
These are tried and tested over many years and have proved to be a reliable technology with the depth of discharge down to 50% they have a long life cycle are designed for slow Charging which is perfect for solar power systems.
The disadvantage is they are large, heavy and take up space
Lithium Iron Phosphate.
The main advantage is size, weight, portability and speed of charging which is great for electric cars and computers etc. but not too relevant to solar power but nice to have. The depth of discharge is said to be greater than than deep cycle batteries.(down to 80%)
The main disadvantage is the technology has not been around for long and has not stood the test of time. The other is the cost. Lithium iron batteries are more expensive than than AGM tubular gel batteries.