[chbot] Power Meters and Solar PV

[Richard Jones]

The topic of power meters came up a couple of meetings ago. I just put two
new batteries in mine which is labelled *EMA*-*1 CS07442V. *And found a
useful user guide here:
https://sites.google.com/site/ema1powermeter/elto-ema1-power-meter. It
turns out that there are two types of meter that look similar, but with
different measuring circuits and accuracies. I took the meter apart to try
to figure out if its likely to read peak, mean, true RMS or something else,
but no clues. As the meter displays power factor I suspect that it does
calculate some kind of power rather than VA. I wonder how it gets on with
non-sinusoidal current draw?

The solar PV system is now up and feeding excess power to the grid via my
export meter http://118.93.103.107/ and I'm getting interested in what kind
of power is drawn when by each domestic device. I'm currently metering the
washing machine, the fridge freezer comes next.

Has anyone looked into which power retailers do interesting power buy back
deals? I'm putting together a spread sheet to help me figure out the best
retailer and tariff, its proving to be a little more complicated than I
thought at first. For example, it might pay me to put my hot water heating
on a timer to use power when I'm generating with Meridian Anytime plan, but
there's no need if you deal with Mercury as they aggregate units in and out
over a 24 hour period and pay/charge for the difference at about 5c/25c per
kWh respectively.

Other thoughts anyone?

Richard
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