Creative ideas to solve my problem?

have a look at this thread:-

http://www.homeautomationhub.com/content/script-switching-onoff-water-he...

also you could just message him? he is fairly active so will probably be along soon anyway :)

dean

The script is a work in progress at the moment but I have a version, although, it doesn't quite work correctly.

If you look at my PVoutput data

http://pvoutput.org/intraday.jsp?id=3748&sid=2946

which is posted via Pachube, you'll see  that the power consumed occasionally drops to 0.

I've taken the view that if I'm exporting to the grid then I'm not consuming any power and therefore I record a value of 0. The script is based on the assumption that if you are generating more than your house base consumption that you can tell if the figure on the meter tail is an import or an export.

 

This is done as follows:

if solar gen > normal house consumption then

 additional power = (power on meter tail - (solar gen - normal house consumption))

As I say it doesn't quite work as you can see from the traces on my PVoutput readings or my pachube readings. (36589)

I've attached my versionof the script if you want to have a play.

OK these are 2 facets of basically the same problem, which is how to maximise the use of "surplus" power generated by a solar PV array. I don't know how much of the other threads you have managed to read through but I'll give a quick summary of the situation as I see it.

The ideal way to do this seems to be with Dean's hardware modification which detects whether the consumer meter is importing or exporting. If you can know for sure then it is relatively easy to switch appliances on or off using RF.
If you haven't got the capability to detect import/export for certain then you are left with trying to work it out. All of the methods which I have tried so far seem to be "hit and miss".

Jamesg says that, for him, his script allows him to basically produce all his hot water in summer for free. The problem is that his script is written for an old version of the plugboard and will not work on the latest version. I have tried to modify the script to work with the latest version but in my experience it's not very successful with my setup. That said, I don't actually have the 2 500 watt immersion heaters that he uses so I can't test it under the same conditions. He says that it works for him, and that is all he really needs to know. It may be that my conversion of his script is not particularly accurate ( I don't fully understand the script ) or it may be that in order to work correctly it needs to be switching 2 500 watt heaters. The thread is here:

http://www.homeautomationhub.com/content/script-switching-onoff-water-he...

"EJ-Ambient" contributed to the discussion with his ideas about how to calculate whether the house was importing or exporting and he is tweaking his script to try to make it more accurate. I don't know if you have tried the script that I posted the other day, but that is my modification of his idea. Again, for me, it doesn't quite work because it randomly reads that I am importing when I'm exporting and vice versa. This may be because establishing what the "base load" of my house has not been done accurately enough.

At the moment I am not actively modifying the script because I'm away from home until the end of May. I'll probably have a go at tweaking it again when I get back.

To sumarise: my view is that with a hardware detection system then switching is fairly straightforward without one it is pretty unreliable.

Allan

I have an old meter as well. I told my supplier more than 9 months ago but they haven't bothered to replace the meter. And yes it goes backwards when I feed the grid. :-)