Grid Tie - basics

[GrahamG]

I have been following the set of solar YouTube videos by Mike but I must admit that I am confused about the Grid Tie option.

Whilst I realise that a DC battery system is charged when the incoming grid power is available Mike suggested that a grid tie unit also does this.

How come the inverter is bi-directional ?

[ShaughnK]

There are more qualified people than I to answer you. But till they come along .... 

In the strict sense a Grid Tie system doesn't have batteries.it is a pure solar option. It uses the Eskom Grid as its battery.

When you add batteries to a Grid Tie system then generally the batteries will have their own inverter/charger which manages them. This is known as AC coupling.  here is a link to an explanation.

http://www.backwoodssolar.com/ac-coupling-explaination.

Hope this helps.