Is it spring yet?

This is more like it, but is only one day!

Most of our import (and today it is likely all of our import) was 2am to 5am at 14.71p.

Most export was during the day at 15.08p.

A lot of export, around 15kWh (54MJ) was 4pm to 7pm (actually 5:30pm to 7pm so we save some for evening) at 24.93p

Doing the sums I think...

• Import 34.1kWh (122.8MJ), assume 14.71p, £5.02
• Export sunshine, 26.7kWh (96.1MJ) at 15.08p, £4.02
• Export battery, 15kWh (54MJ) at 24.93p, £3.74

Total electricity bill (excluding standing charge) -£2.74, and that left some in the battery still.

Without solar and battery? House used 31.4kWh (113MJ) and would have been mostly 24.51p, so £7.70.

If only every day was like this.

Solar install, part 2 (tasmota/shelly EM)

Read part 1 for more background. See my blog on power monitoring.

I installed monitoring for power usage a few months ago. This is using Shelly EM power monitoring modules with current clamps, reflashed with tasmota code. It works well, I have some nice graphing stuff (all on GitHub).

Now I have the solar panels I have to allow for "negative" power flow, i.e. exporting to the grid.

Sadly it did not work, and my googling did not help. I raised a question, and apparently this has come up before #15315, #12861, and a merge #12874, great. So the current code should handle the ADE7953 sign bits and do negative power.

The problem was that I was not seeing negative values at all, so my graphing is all messed up as all export shows as import. Very frustrating. I even went to building tasmota code myself, and no joy.

However, I found a clue, in the later source code (after that merge), it has a model flag to indicate if Shelly 2.5 or Shelly EM, and it only does the negative power on the Shelly EM. This has to be a clue.

I tried the config template from the code, and nothing happened. Still not working. After a lot more reading of the code I worked out the issue.

It is subtle, but the "2" next to the ADE7953_IRQ, rather than "1" seems to be the trick here. Of course, changing to "2" did not fix it - because I was exporting AND I had the clamp backwards so still seeing +ve (import) figures only. Fixing the clamp as well, and now it looks good.

Now I have graphs that show negative (export) power, at last. I have to tweak my graphing code to allow for that next...

And yes, the sun is shining a bit now...

Part 3