Building a new Solar Array

[warlock]

Hi Guys,

Well Eskom our electricity supplier managed to convince our government that they need to increase out rates in order to payback their infrastructure cost in about 5 years, they have also manage to convince me it's time to go solar.

So I am looking to install an array to start with I am looking at 10 x 300w panels all attached to micro-invertors and then attached to a grid-tied system,
Currently I know we can't feed back into the grid legally.  My questions are how do you size the grid-tie invertor, I will want to grow the array, I think my roof could support probably 20x300w or 25x300w panels, which grid-tied invertors are good, do you get invertors that support both on grid and off grid, I don't think I will for now install a battery bank, but if after a year I the municipality has not started to allow it I would probably start looking at batteries,
Which invertors are required and supported in SA with regard to frequencies ect. "what frequencies are used in South Africa"

Do the meters in the boxes currently run in reverse if one did just feed back into the grid " mine is the spinning type" and are there any good site which step you through building an array.

Any help would be appreciated.

[SeanB]

Don't know about the inverters, but I would hazard any inverter that will grid tie an Australian or SA 230V 50Hz system will work. As to inverters that support both grid tied and non tied operation I do not think they are available, as then they can feed back into a faulted grid. You probably will need 2 and either a switch to change over or run some loads via the inverter only. as to the meter it depends, some have an anti runback lock so they can not be run in reverse ( quite common as there was a simple way to get them to run backwards by connecting a load near full current but with a very poor power factor of less than 0.1 like an open circuit MMA welder) while others are happy to run in either direction depending on power flow. Depends on the make and model of meter and the supplier requested options during ordering.