Speak EV - Electric Car Forums banner

1 - 1 of 1 Posts

·
Registered
Joined
·
1,006 Posts
Discussion Starter #1 (Edited)
I had Solar PV & and ABL Sursum EVSE installed by @Thomas_Newby back in 2015. A few weeks ago I finally got my act together and connected a Raspberry Pi to the RS485 port to control the EVSE's advertised charge to my Outlander.

I went through a few iterations involving battery powering a Pi Zero with a small USB solar panel and WiFi but after some frustration went with a hard wired Pi 3 in a waterproof box.

The generation and consumption data come from an Open Energy Monitor emonpi (another Raspberry Pi device) via MQTT to node-red running on the outdoor Pi3. The EVSE is controlled via a "WiFi Relay" also attached via MQTT and is not on all the time, only when I have more than 7A available from the solar. Reasons below;

Today was only about the third time the car has been charged this was during the day and apart from a slight hiccup on my part while fine tuning the node-red settings it was fully automated.

Things I would note, before some pictures:

1. The Outlander will consume what it considers 6A even if you advertise the lowest current of 4.8A
2. Sending the control signal of "Charging not available" does stop the car charging but after a while it stops the car charging to the point I had to unplug and turn the system on before it would recommence charging. I have to test this again before thinking about reenabling this.
3. The charge control stepping of 0.6A up or down means that you will never follow the curve of the solar exactly.
4. Given the way the car charges from regenerative braking I see no problem with varying the charge current in real time.
5. This is fun and given the additional cost of bits (Pi3, USB serial adaptor, outdoor case, Powerline adaptor for the porch, USB adaptors) it may even pay for itself after a year or so. I save both the E7 charge (about 60p) and also get paid for generating the power I charge with (£1.40) - so I get "paid" £2 for putting 10kWh into an empty car :) The pics below show the car wasn't completely empty.

Here is the last 8 hours, orange being the car charging:

upload_2017-4-5_16-46-54.png


Zooming in a bit to 1PM when I got 4kW+ for a bit (first week of April!) you can see that the charge almost but not quite follows the supply:

upload_2017-4-5_16-48-8.png


The node-red flow is quite custom, but happy to share if anyone wants more.
 
1 - 1 of 1 Posts
Top