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Really basic getting started question

(Brian Drury) #1

I have an existing grid tied PV system which uses the Martin Roberts design of energy diverter. This has worked well for many years and now I have added an OpenEVSE charge controller plus Emonpi with the plan to charge an EV with surplus PV power.

The OpenEVSE has a WiFi connection to my network and the Emonpi is also connected by WiFi to the same network. Both connections appear to be working OK.

After much rummaging through the documentation I managed to get some sensible looking data from my type 1 system appearing in my remote Emoncms account. However, when I initially tried to follow the setup instructions for the Emonpi I first used the device setup shortcut, or at least I would have if I had not fallen at the first hurdle.

Maybe someone can help as I must be doing something really stupid.

The instructions say this:

Device Setup shortcut

For new installations, if you have connected:

  • CT1 (power 1) = grid import (positive) / export (negative), and
  • CT2 (power 2) = solar generation,

then you can use the shortcut menu Setup > Device Setup to configure your inputs automatically.

Click on the spanner icon next to your emonPi, and then from the left-hand menu choose OpenEnergyMonitor > EmonPi > Solar PV Type 1/2 (as appropriate). Click Save and it will create or reset your Input configurations to the recommended values.

Clear enough but when I click the Setup tab I don’t see a Device Setup option so I am then stumped. Can someone please advise what I am doing wrong?

(Robert Wall) #2

Welcome back, Brian.

I don’t quite understand your set-up. Are you using the emonPi as intended, i.e. with two c.t’s and a.c. adapter, or are you using Martin’s diverter’s c.t’s for the grid and PV monitors? How does the data get from Martin’s diverter to your emonPi? And by “my remote Emoncms account” do you mean emoncms.org?

(Brian Drury) #3

Hello again Robert and thank you for the response.

I am using the emonPi as intended with two ct’s and AC adapter. I decided not to touch Martin’s diverter as it is doing such a fine job so the plan is for the new emonPi system to have priority when surplus PV power is available.

Yes, I am using emoncms.org.

(Brian Drury) #4

Maybe a drawing will help:

(Robert Wall) #5

I think it needs an emonCMS expert to sort this one, which I’m not. I did wonder whether you had used Martin’s diverter’s data and called it “power 1” and “power 2” - because I think that the setup recognises the names, which I think should instead be “power1” and “power2” as they are in the default emonPi.

(Brian Drury) #6

So, on to the next problem. The screen grab shows the Solar Divert figures for today. As you can see if we ignore the negative sign the house figure of 3117W equals the Solar figure of 3117W which agrees with the Martin Roberts data in the sense that the system is balanced and working correctly.

The Divert figure of 2761W is approximately correct and if we ignore the sign for the Total Use figure of 356W and add it to the Divert we get 3117W. The Exporting figure of 3473W appears to be House – Total Use but I don’t know what that is supposed to mean.

What I was expecting is:

House = 356W

Total Use = 3117W

Divert = 2761W

Exporting = 0W

Reversing the consumption CT does not change the sign.

Is the position of the consumption CT on my diagram correct?