Hi @wborn, did you consider and reject using BigDecimal since accuracy and precision are factors here?

    private static final BigDecimal PULSES_PER_KW_SECOND = new BigDecimal("468.9385193");

    private static final BigDecimal PULSES_PER_W_SECOND = PULSES_PER_KW_SECOND.movePointLeft(3);

etc.

I just rewrote the calculations to BigDecimals and found that the percentage error of using doubles in the calculations is: 0.07984247352300347106 %

So I would prefer using doubles over BigDecimals because:

• the error is small
• the code is easier to understand with doubles
• double calculations use less CPU/memory
• the calculations now have exactly the same results (but with more decimals) as stored in the Plugwise Source database. This also makes it easier to compare and validate the correctness of the Plugwise Binding calculations.

That sounds like a valuable exercise you went through. Do you think this PR is ready to merge?

Yes I've been using this code without any issues for a week myself now.

Now that the measurements are the same as Plugwise Source, I store the "last hour" kWh values in influxdb and use them in Grafana to draw nice charts. :-)

Should 6ee86c1 be cherry picked to the 1.9.x branch so it appears in the 2.0.0 release (I'm guessing yes, but WDYT)?

Thanks for merging @watou . Yes it would be nice when it is cherry picked so it also to appears in the 2.0.0 release. I think it will be my last Plugwise 1.9.x contribution since it is more or less feature complete for me now. My next contribution might be a real openHAB 2.0 Plugwise Binding. ;-)

My next contribution might be a real openHAB 2.0 Plugwise Binding. ;-)

That will be very well received! Thanks so much for your contributions. I will make sure this PR gets into the 2.0.0 path.

Cherry picked onto 1.9.x branch.