Did you succeed with accessing the TWC3 via RS485?
Since a few days, there’s a new firmware version available: Firmware 23.44.0 Details | Wall Monitor
Best Regards
Tobias
Not yet, I had trouble to get the wire connected. And its a bit too cold and dark outside to try it again.
Might try again later 
Teslemetry is using the new FleetAPI that records the VIN of the vehicle charging on a TWC3.
Is there any API exposed on the Gen 3 wall charger that allows me to start, stop or adjust the charging current?
I have a non-Tesla car and its APIs/HA integration are poor, so i want to instead try to control charging from the Gen 3 wall connector instead.
Have you meanwhile tried it again? If yes, which RS485 ID, Baud Rate, Data Size, Parity, Stop Bits have you used? Thanks in advance.
Unfortunately the documented Gen3 API doesn’t support changing any settings.
It would really drive the transition to sustainable energy if Tesla could adopt charge point standards like the Open Charge Point Protocol (OCPP) via a firmware upgrade.
This may be of interest: GitHub - ngardiner/TWCManager: Control power delivered by a Tesla Wall Charger using two wires screwed into its RS-485 terminals.
Appears to talk to use RS485 to talk to the Power Wall. However, they specially call out that the newest version isn’t tested:
We do not currently have enough information about the new 2020 Tesla Wall Connector devices with WiFi to understand if they will be compatible in any way (wired or wireless) with TWCManager.
But I have a feeling it could be made to work, if a brave soul is willing to test…
I’ve already tried the TWCManager approach, unfortunately without any success so far.
I was not even able to find out the correct MODBUS RTU/RS485 settings, starting with the baud rate, which is set in TWC Gen 2, according to /etc/twcmanager/config.json:
# TWC's RS485 port runs at 9600 baud which has been verified with an
# oscilloscope. Don't change this unless something changes in future hardware.
"baud": 9600
Therefore I used an RS485 to ETH device from WAVESHARE and scanned via MODBUS RTU over TCP (not MODBUS TCP) for all possible RS485 IDs, RS485 adresses/objects, all possible baud rates, …, fully automatic over lots of days, without any hit.
I assume, that lots of other people also tried the (most obvious) TWCManager approach with their TWC Gen 3 within the last years. If anybody of them had suceeded, we would already had got to know.
I’ve also been asking the TESLA TWC support for 2 years for any documentation, hint, timeline regarding the introduction of RS485 for TWC 3. In the beginning, they always said, it will come, but they don’t exactly know, when. Meanwhile the non-personal mailbox of the support team is unmonitored, maybe they all have been layed off.
Well that’s unfortunate.
Someone has figured it out though: https://www.amazon.co.uk/Neurio-Technology-Dynamic-Power-Charging/dp/B0CYM4FJ4P/ref=sr_1_11?crid=3PGL4HHMNZ3E1
Maybe they got documentation somehow.
Thanks for the information. This is really very interesting.
I tried to reach the experts from Neurio. After writing a mail to them, a Customer Support Technical Specialist from Generac (the company, which aquired Nurio in 2019) answered me, that I have to contact Tesla directly, because a separate division of Neurio developed the device.
A hotline guy of Tesla in the U.S. told me, that maybe the firmware of the European version, which I have (3 phases with maximum 32A) may behave different from the U.S./Canadian version (1 phase with maximum 48A). I asked for any documentation. He confirmed, that the U.S./Canadian TWC3 version has RS485 support, but said, that there’s no documentation regarding baud rate, register, … only the Neurio installation guide.
Is it possible to limit the Ampere of the Wall Connector with Home Assistant? So max 32 and lowest 1? And can i start/stop the Wall Connector 3 in Home Assistant?
None of the above
After finding out that the Tesla API calls are now limited and will maybe soon be chargeable and finding out today that all my home assistant automations for charging are now broken, I have a renewed interest in getting this working.
Okay, so… hear me out.
Can we (royal “we” maybe) buy the device I found (https://www.amazon.co.uk/Neurio-Technology-Dynamic-Power-Charging/dp/B0CYM4FJ4P/ref=sr_1_11?crid=3PGL4HHMNZ3E1 - I also found related documentation here: https://digitalassets.tesla.com/tesla-contents/image/upload/NA_Wall_Connector_Smart_Current_Limits_App_Note_EN.pdf ) and hook that up.
But then send fake signals via the CT clamps to trick the device into thinking there is no spare capacity and then telling the wall charger to back off and stop charging. We could then vary the fake signals to adjust the wall connector for automated charging via home assistant and solar charging etc.
Presumably the “worst that can happen” is wasting money and time and the car not charging when we want it to, as presumably the worst signal we can send is “plenty of capacity on the circuit, go for it and give it all the amps you’re allowed to” which I assume is how the setup is currently.
Is this crazy? Or crazy enough to work?
Could work but for that kind of money you may as well just buy an OpenEVSE instead and have full control
Yeah good point.
I think I’ll do some hacking on the Android app instead.
Hello.
I gave up on hacking the Android app. I did make limited progress by setting up a VM and running it there and was going to fake button presses etc, but then decided against going further because I’m a coward and don’t want to upset Tesla.
So… to the RS485 port. I’m getting data through it. Are we thinking that no data comes through this port?
It’s just question marks though, one every 2 seconds. But I am seeing something and the receive light on the USB to RS485 dongle I bought is very briefly flashing. It’s like the wall connector is sending a “are you there?” signal, but I don’t know how to reply.
Is this progress or no?
When I go to “File” then “Save RAW file” I get the attached in both a text editor and using the xdd command. This is a fresh session for just a few seconds. Screenshot is below.
I very clearly have no idea what I’m doing, but I’m willing to learn and test as long as there isn’t a risk of damage to the Wall Connector or the car.
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Thanks for sharing your results.
When I was playing around with the scanner (to find out the correct baud rates & RS485 adresses), I also had received sporadically data/response from the TWC3, but it was no proper MODBUS RTU response, which could lead to any further progress.
I assume, that any device, which wants to communicate with the TWC3, has got to initiate a special “handshaking” and/or “certificate exchange” and/or has got to send “permanent keep alive data”. This is also my conclusion after I scrolled through the Neurio documentation.
By-the-way: Meanwhile, I was able to reach EMEA TWC support. When I asked for documentation (and told them, that it seems, that it works with the Neurio device), they simply adviced me to buy the Neurio device. So for me, it seems, that they are not willing to disclose the TWC3 RS485 mechanism at all.
I see. My understanding was that we got no data at all, so obviously you can understand my excitement at seeing data yesterday, even if I didn’t understand it.
Would reverse engineering the firmware be an option?
If the firmware is not encrypted, this could also be an option.