TWCManager

TWCManager let's you charge when green power is available and your not using it in the house. TWCManager lets you control the amount of power delivered by a Tesla Wall Connector (TWC) to the car it's charging. This can save around 6kWh per month when used to track a local green energy source like solar panels on your roof. It can also avoid drawing grid energy for those without net metering or limit charging to times of day when prices are cheapest.

Due to hardware limitations, TWCManager will not work with Tesla's older High Power Wall Connectors (HPWCs) that were discontinued around April 2016.

UPDATE: TWCManager will also not work with Generation 3 TWCs released around Jan 15th 2020. Sadly, gen 2 TWCs are no longer sold by Tesla and may become hard to acquire over time. We don't expect to add support for gen 3 TWCs unless their wireless protocol is reverse engineered by a third party.

See TWCManager Installation.pdf for how to install and use.

This TWCManager fork works with utility mains current measuring:

Follow the instructions in TWCManager Installation.pdf to install TWCManager.

Download the forked code to your raspberry pi using this git command:

$ git clone -b master --single-branch https://github.com/BitterAndReal/TWCManager.git~/TWC

If we measure how many amps are drawn at the utility mains we can protect the main fuse of your house.

And we can use the mains reading to calculate how much green energy we have left to charge the car.

There are a few new configuration parameters in TWC manager:

UtilityMainsFuse = 22            # set UtilityMainsFuse to 90% of the utility mains fuse rating of your house
SocketServerIP = '192.168.0.67'  # The socket server's IP address
SocketPort = 65432               # The port used by the server

I used the following Raspberry pi zero shield to measure the utility mains current:

3 current and 1 voltage adapter http://lechacal.com/wiki/index.php?title=RPIZ_CT3V1

http://lechacalshop.com/gb/internetofthing/63-rpizct3v1.html

This fork is if your TWC and utility mains are far away from each other. We use two raspberry pi's connected to the same network. One with TWCManager and one with the current measure shield.

The current measure shield could be on the same Raspberry Pi as TWCManager is running. But you would have to add the serial read code from socket-server.py to the TWCManager.py script and remove the socket part.

this is how you prepare the pi to run the socket-server script:

Follow the instructions in TWCManager Installation.pdf to install OS on Raspberry Pi Zero W and set up wireless access to Pi with a static IP.

If you got a ssh connection use this commands to install the necessary software:

$ sudo apt-get update
$ sudo apt-get install -y git
$ sudo apt-get install python3-pip
$ sudo python3 -m pip install pyserial
$ sudo apt-get install -y screen

copy socket server script to PI:

$ ​sudo nano ~/socket-server.py

copy the code of the file socket-server.py into it and save it

to start the socket server at boot:

$ ​sudo nano /etc/rc.local​

Near the end of the file, before the ​exit 0​ line, add:

su - pi -c "screen -dm -S socketserver sudo python3 /home/pi/socket-server.py"

How to make serial work on the Raspberry Pi3 , Pi3B+, PiZeroW:

$ sudo raspi-config
Select Interfacing Options / Serial
then specify if you want a Serial console (no)
then if you want the Serial Port hardware enabled (yes).
Then use /dev/serial0 in any code which accesses the Serial Port.

$ sudo apt-get install python-serial
$ sudo reboot

utility mains measurement

I added the current measurement and basic connection errors to the Web interface.

TWCManager calculates an average over 4 sec to make the charging current changing a bit les agressive. After the averageing we use the highest averaged phase current in the past few minutes as protecting limmit. A small current spike should not trigger the main fuse.

For green energy tracking we calculate an average every 5 minutes.

debugging of current measure pi

After you have a ssh connection to your current measure pi you can open the status screen with:

$ screen -r socketserver

Make changes to the socket-server.py script with:

$ ​sudo nano ~/socket-server.py

alternatively use DSMR-reader for dutch smart meter

If you want to use the dutch smart meter to read the AC utility mains current you could try DSMR-reader for Raspberry Pi This is not tested and not part of this fork but could be a good alternative for the current measure shield.

# DSMR-reader has the following RESTful API.
# documented here: https://dsmr-reader.readthedocs.io/en/latest/api.html#example-2-fetch-latest-reading
# Requirements:
#   Smart meter DSMR version: v2, v4 of v5
#   Hardware: RaspberryPi 3
#   OS: Raspbian OS
#   Python: 3.6+
#   Database: PostgreSQL 9+
#   SD disk space: 4+ GB
#   P1 telegram cable (RJ11 to USB)

# Request power from DSRM-reader API:
import requests
import json

response = requests.get(
    'http://YOUR-DSMR-URL/api/v2/datalogger/dsmrreading?ordering=-timestamp&limit=1',
    headers={'X-AUTHKEY': 'YOUR-API-KEY'},
)

if response and response.status_code == 200:
    json_data = response.json()
    if json_data and 'results' in json_data:
        if 'phase_currently_delivered_l1' in json_data['results']:
           MainsAmpsPhases[0] = results.get('phase_currently_delivered_l1')*1000/230
           MainsAmpsPhases[1] = results.get('phase_currently_delivered_l2')*1000/230
           MainsAmpsPhases[2] = results.get('phase_currently_delivered_l3')*1000/230
#          phase_currently_delivered_l... (float) - Current electricity used by phase L... (in kW)

      else:
        if debugLevel >= 1:
            print('DSRM-reader Error: {}'.format(response.text))