Works on ESP32 and ESP8266 on 3V Lithium Battery

[TPD95100]

Dear Fredilarsen,

thank you so much for publishing this code. It works in my 2022 Tesla M3 delivered in December 2022 in Germany. I checked it on ESP32 and ESP8266 boards with 3V supply from a CR123 battery. The voltage is sufficient for both, the uController and the STX882 (I use it with the antenna). Boot time is less than 100ms, so, it works instantly.

I also added a 3V relay - both, the ESP8266 and the relay are directly powered by the battery thru a momentary switch (so, the relay is not connected to the ESP). The relay is used to switch the resistor for unlocking the charge plug. For the 22kW plug I use, two 220 Ohm resistors are in series, one so shorted by the relay when the switch is released. If the switch is pressed, the relay is actuated and opens the short so that the resistance increases to 440 Ohm which unlocks the plug. So, here, the NC pathe of the relay is used.

For a 11kW cable, one need to put a 1200 Ohm resistor in parallel to the built in 680 Ohm resistor. The relay is in series to the 1200 Ohm resistor on switched „on“ to unlock the charge plug. So, here, the NO path of the relay is used.

Details in thus in German here: https://blog.thesen.eu/tesla-command-button-beenden-und-entriegeln-des-steckers/

With an ESP8266 D1 Mini, I could fit everything in a Europen Type 2 plug. With just one switch I can now do both, open the charge door and release the charge plug.

With a CR123 lithium battery, it will last probably 10 years …

Best regards

Thomas

[fredilarsen]

Thank you for the feedback, and the link to your useful blog.
I actually solved the unlock button problem previously in another way, but your way would have been simpler.

My solution let the button (on the wall holder, not the cable) be registered by an Arduino Nano (the same that sends the open charge door radio signal when I pull the plug out of the wall holder) that is hooked up to a single-pin communication bus using my ModuleInterface/PJON repository. This bus is in turn synced with a MQTT broker and then using Home Assistant to trigger the "unlock cable" command in the Tesla web API when the MQTT topic changes. More steps, but I used already installed home automation infrastructure at home, and it works beautifully with very low delay.

I also have a config parameter that let me set whether to use the radio signal or to ask the Tesla web API to open the charge door. Both work fine.

[lylus]

Dear Fredilarsen,

thank you so much for publishing this code. It works in my 2022 Tesla M3 delivered in December 2022 in Germany. I checked it on ESP32 and ESP8266 boards with 3V supply from a CR123 battery. The voltage is sufficient for both, the uController and the STX882 (I use it with the antenna). Boot time is less than 100ms, so, it works instantly.

I also added a 3V relay - both, the ESP8266 and the relay are directly powered by the battery thru a momentary switch (so, the relay is not connected to the ESP). The relay is used to switch the resistor for unlocking the charge plug. For the 22kW plug I use, two 220 Ohm resistors are in series, one so shorted by the relay when the switch is released. If the switch is pressed, the relay is actuated and opens the short so that the resistance increases to 440 Ohm which unlocks the plug. So, here, the NC pathe of the relay is used.

For a 11kW cable, one need to put a 1200 Ohm resistor in parallel to the built in 680 Ohm resistor. The relay is in series to the 1200 Ohm resistor on switched „on“ to unlock the charge plug. So, here, the NO path of the relay is used.

Details in thus in German here: https://blog.thesen.eu/tesla-command-button-beenden-und-entriegeln-des-steckers/

With an ESP8266 D1 Mini, I could fit everything in a Europen Type 2 plug. With just one switch I can now do both, open the charge door and release the charge plug.

With a CR123 lithium battery, it will last probably 10 years …

Best regards

Thomas

Hello, TPD95100. I am planning to use esp mini d1 to use this feature. Can you take a photo of your finished product for my reference? Also, can I simply change the output gpio number for the code? thank you very much.

[fredilarsen]

@lylus Did you follow the link to the blog of @TPD95100 ?
Lots of nice pictures there, but more of the plug than the device.

[danergo]

@fredilarsen, @TPD95100:

Isn't it ruining the charging to use the same button for these two functions?
1.) Open door flap (by sending RF) and
2.) Modifying resistor

If cable isn't plugged in, modifying resistors value doesn't seem causing too much harm but in theory, can it bother the charger station?
I usually make the below sequence for charging:
1.) Plug cable into street charger
2.) Plug cable into car

Now with this addition, pressing the button would be inserted in between, ie.:
1.) Plug cable into street charger
2.) Press button (causing sending RF and altering resistor)
3.) Plug cable into car

Now questions:
1.) Doesn't this cause problems for the street charger?
2.) What happen if I press and hold button while plugging into car? I.e.: is this solution 'fool-proof'?
What does Tesla when sees a charger with incorrect resistance? Will it deny charging then start once I release the button?

[fredilarsen]

@danergo I have not used the solution of modifying a charging cable myself, so I hope @TPD95100 has some insights related to your questions.

I have the sender in my 3D-printed charging cable wall hanger, with a microswitch that triggers the opening of the charging door when I pull the plug out of the wall hanger. This is where I charge my car 99% of the time, so I have not seen the need for having a modified cable.