OpenEVSE Solar Divert Setup

nigeldodd · 2022-04-07T14:54:49.081Z

Now it’s sunny, I’m trying to charge my Tesla from the solar panels. They are generating 3kW, the exported power is available on the mqtt channel power1

mosquitto_sub -v -u ‘emonpi’ -P ‘emonpimqtt2016’ -t ‘emon/#’

emon/emontx1/power1 -1547
emon/emontx1/power2 2288

On the openevse Services page and “Solar PV Divert” panel the Feed is set to
Grid(+I-E) 192.168.1.136/emontx1/power1 but no charge happens
if I change it to emon/emontx1/power1 still no charge happens.

I am not sure how this line should work since is it is a mqtt topic. I am not sure how the charger knows the IP address of the emonPi.

Any ideas please?

glyn.hudson · 2022-04-07T15:35:13.364Z

Does the OpenEVSE say “MQTT connected: Yes”?

The OpenEVSE can usually connect to the emonPi using the local hostname e.g http://emonpi or http://emonpi.local. You could change this host field in the OpenEVSE to use the IP address of the emonPi, but this could change unless you have reserved it.

Screenshot from 2022-04-07 16-33-18418×929 39.9 KB

nigeldodd · 2022-04-08T10:57:52.000Z

Thanks, Glyn.

My ip address 192.169.1.136 is fixed.

I think I have just got it working. I had misunderstood the role of mqtt but assumed it was working since I was getting valid data received in http://192.168.1.136/emoncms/input/view.

In reality mqtt was not working because I had not put the emonpi emonpimqtt2016 credentials into the panel on the openevse. Now, to my huge gratification, it seems to be working

image.png969×373 27.1 KB

I do not understand why emoncms was getting data without mqtt working on the evse. What is mqtt needed for and what is it not needed for?

Thanks again for your help.
Nigel

glyn.hudson · 2022-04-08T11:34:56.671Z

Nice work.

You can post data to Emoncms using HTTP using the HTTP service. However, for the EVSE to be able to receive data from the emonPi for solar PV divert MQTT must be used.