[wodahs]

Originally Posted by AlanD

Hi, answer to second question first. I do not know, except that the capacity of the off grid system might not be able to provide power to the premises in the longer term when weather conditions do not allow sufficient charging across a number of days. In that circumstance you might want to be able to access grid power, eg restaurants do not want foodstuffs, either fresh or pre-prepared to spoil.

First question, which I think, is that you want to know if the capacity of a system that can be connected to the grid, or stand alone, wastes that part of its capability that is not being used to power the premises when it is off grid? Well, you could argue that it gets wasted, but better to understand that the generator simply adjusts its output to match the load that is being supplied. In the case of a PV array feeding an inverter the dc input current falls to match what the inverter sees on its output side. If the generator is an ICE driving an alternator it simply uses less fuel and can last for more hours.

Zilo's changeover switch concept can be automated and is for places like Hospitals and airports, where loss of grid power could be life challenging. (You don't want operating theatres or lead in to runway and runway lights suddenly being without power - bit disconcerting for surgeons and pilots.)

I own an ICE powered alternator, but connecting it up to the house so that all I have to do is start the thing up is a challenge because the alternator location is remote from the distribution board and I do not have a dedicated feed circuit for it. Also I'm not sure if the output frequency is stable enough to get the PV system inverter working. Still working on a solution for this.

Hope I've helped.

Cheers

this i fully understand and did at the time i answered the question to which i was commented on that led to this (refer further up to original question)

Originally Posted by zilo

Just waste...but giving power to multinational companies virtually for nothing is not waste in my opinion..it gives more options for self consumption.
I would rather operate an aircon with all the windows open rather than sell at 4c/kwh...but that's just me...

and yet even be it only a small amount i was getting more than 4c (was around 47c) and with the new changes i will still get more than 4c (around 10c and i do agree it should be more ) but it is still better than nothing and offsetting my connection fee

Originally Posted by zilo

It make for a true non stop power system...rather than run a generator you use the grid for automatic emergency backup...can be a lot less maintenance and no skills required by the operator....having said that a 100 bucks a quarter buys a fair bit of diesel...

which negates the question i was answering if you would like to go back and refer to it

in the event that the Grid goes down
I understand that grid-invertors are designed to shut-down by default
The result was that in the event of grid failure, you could not isolate and power your own home.

so as asked to power the house durin a grid failure event not power the house from the grid when the batteries are flat
i can and do with the situation i have stated above
and i am grid connected