Tesla Wall Connector load sharing protocol

[Utahken]

I reached out to Tesla concerning the RS-485 port and here is both my question and their response:





I also reached out asking about the wiring protocol since up to four Gen 2 units could be junctioned to a single breaker but the Gen 3 manual wants a separate breaker for each unit. They confirmed that each unit will need to be on it's own breaker.

With that I'll be doing a bit of re-wiring. I had setup a junction box already that has three 6-gauge wires (two load, one ground) in a 3/4" conduit running from the breaker then branching off to two wall connector locations. Could somebody help me determine if it would be safe to upgrade that conduit to a 1" conduit with five 6-gauge wires (four load, one ground) for a two connector setup? A grounding block inside the junction box would then split the 6-gauge ground and dedicated load wires will continue on to the connectors. I'd be pulling 40 amps off 50 amp breakers, with possibly going up to 48 amps on 60 amp breakers later.

Alternatively I could just let the junction box serve one of the locations and just run a separate conduit for the other, just figured it would look cleaner running them both through the junction box as long as it is safe and up to code to do so.

This is all inside the garage in a dry location.

Thanks for asking Tesla those questions.

As for the separate breakers... if you are going to load share then you only need one breaker and 1 run that is branched, that is the purpose of the rs485 communications and load sharing. If you are not load sharing then a separate breakers is needed for each WC with it's own dedicated wire run.

 

[Mokuzai]

if you are going to load share then you only need one breaker and 1 run that is branched, that is the purpose of the rs485 communications and load sharing. If you are not load sharing then a separate breakers is needed for each WC with it's own dedicated wire run.

That is the case for Gen 2 chargers, and how I was wiring everything prior to the Gen 3's coming out. The Gen 3 uses wireless load balancing for up to 16 chargers (well not yet but that's their plan with an update) and the manual wants you to have each charger on it's own breaker even though they are load balancing. Tesla confirmed this to me over the phone.

 

[israndy]

That seems odd, if you can pull the power from a single breaker to feed a subpanel, why not just make that branch feed all the 3rd gen WCs and set them to load-share that 60 amps from the single breaker? Sure you cannot feed 16 WCs that way, but if you just have two in a garage...

 

[Utahken]

That seems odd, if you can pull the power from a single breaker to feed a subpanel, why not just make that branch feed all the 3rd gen WCs and set them to load-share that 60 amps from the single breaker? Sure you cannot feed 16 WCs that way, but if you just have two in a garage...

It looks like a clean way to distribute the power. I kind of like it.

 

[davewill]

That is the case for Gen 2 chargers, and how I was wiring everything prior to the Gen 3's coming out. The Gen 3 uses wireless load balancing for up to 16 chargers (well not yet but that's their plan with an update) and the manual wants you to have each charger on it's own breaker even though they are load balancing. Tesla confirmed this to me over the phone.

View attachment 510291

Honestly, I think a small load center with breakers is a better solution than a junction box with Polaris connectors or some such anyway. I do wonder if they are implying a more sophisticated load sharing config with their one example, like max 60a per WC, but a 100a budget overall, as an example. That would make a lot of sense.

 

[jakkeb007]

Hello,

This is my first post on this forum. I'm waiting for the delivery of my Model X and I'm doing some research for charging possibilities.

I have a 1 phase 40A connection at home (Belgium 230VAC). I want to install a TWC and allow it to charge at the highest rate possible without limiting the use of other appliances in the house. This is my idea for the setup:

- TWC fused at 32A (1phase 230VAC)
- TWC set to slave mode to accept charge current limitation from Raspberry Pi
- Use a CT sensor to measure the total consumption of the house (probably with ESP arduino board)
- When the total consumption of the house exceeds 40A, the rasberry Pi should tell the TWC to lower it's charging current to prevent the main circuitbreaker to jump.

I see a lot of projects using the TWCManager to manage the charging current based on the production of energy from solar panels but I was wondering if someone has tried this before?

This would be very usefull in my opinion. It would allow your car to charge at the highest speed available without compromising the useability of your other appliances at home.

I know there are wall connectors available with load balancers that do the same. But I also want to be able to open the charging port of the car with the charger plug but I cannot find a charger that allows both.

 

[WinterDragoness]

I will confirm the rs485 ports on gen3 do not output anything during normal operation or respond to anything I've tried sending. I don't know why the ports are even there though I theorize they want the option to do something with them in the future, if they ever get around to it.

The manual does not say anything about the rs485 ports but it does say there will be wifi power sharing available "in a future firmware update". No idea when.

Since you can change circuit breaker size over wifi, I tried doing that while it was charging in order to get some control over charge rate, but it seems to turn the wifi off after it's been on for 5+ mins. So wifi config can only be used for provisioning, not during operation.

Internal components of gen2 TWCs were made by Delta, but gen3 internals are all stamped Tesla. CPU is different, there is no obvious JTAG connector, and so the firmware must be a complete rewrite for the new hardware. My best guess is that Tesla is trying to build a walled garden where their products talk to each other over Wifi but they don't want anyone else intruding on the conversation. I'm not sure how difficult that might be to break into but I can tell you that I won't be able to help with the process due to agreements I have with the company I now work for. I'm also concerned that even if someone breaks into the conversation, Tesla may release firmware updates that lock people out again.

Bottom line, TWCManager will likely not get updated to support gen 3 TWCs unless someone else can figure out how to do it. Until Tesla releases a firmware update, even power sharing between two stock gen3 TWCs is not currently possible.

 

[Myfirstone]

Is there somebody how make it working with the SolarEdge HD inverters over rs485 protocol?

 

[PJMikols]

@nick_tassi Any chance to share that code or Fork it in Github? i was about ready to start the process.

In addition I also got some code working to talk to my enphase system, and now I get actual house consumption (minus current charge) to work out total available amps. Worked great yesterday and today.

 

[rickhuizinga]

@nick_tassi Any chance to share that code or Fork it in Github? i was about ready to start the process.

+1

I'm about to start working on interfacing to an Enphase system too

 

[israndy]

Which Enphase system. What are the minimum reqs?

 

[PJMikols]

I have iq6+ and 7+ going to an IQ Envoy.

im not too concerned about matching the production, but curious on method to get the consumption CT to effectively be 0 or slightly positive. (No need to make assumption of average loads when we have real loads)

if anyone has suggestions or has done this we are all ears.

 

[rickhuizinga]

Enphase Envoy with production & consumption CTs. I've found the information on pulling the live production & consumption stats directly from the Envoy over the local network, but it sounds like someone here has already got this working.

For the record, here is the information on pulling the stats directly from the Envoy: https://thecomputerperson.wordpress.com/2016/08/03/enphase-envoy-s-data-scraping/

 

[Myfirstone]

Dear wiz kids,


Is it possible too let it work on a ESP8266?
I have two off them and wondering if this can work?

 

[nick_tassi]

@nick_tassi Any chance to share that code or Fork it in Github? i was about ready to start the process.

See attached code. To work on your system, you should just need to change the IP address, but this is always at your own risk.

Issues noted:

1) Scheduling sometimes fails
2) Car charges when not required at 6A.
3) Stop issues sometimes (restarts not long after).

I would be grateful for anyone to look at this for me.

 

[Myfirstone]

Hello,

Is there someone that can help me? I have a rapsberry pi Zero W with a Adam rs485 to usb converter. I can’t get it work work TWCManager.

when I try too get connect too the charger it go in too error.

 

[Myfirstone]

Is there a cleaner and smaller TWCManager
File soo I can debug my setup?

raspberry pi Zero W
Tesla Wall Charger 32A 3fase europe
Adam rs485 too usb
SolarEdge inverters including a working API key that gave the energy production in a Json file.

problem when I start the raspberry pi the charger go too into error and a reset won’t help. When I disconnect the rs485 connection and reset the charger it will work.

what could be the problem?

 

[PJMikols]

See attached code. To work on your system, you should just need to change the IP address, but this is always at your own risk.

Just loaded into mine, Will monitor over next week or few and see how it does. I did add actual measured Voltage off the Enovy, instead of assuming 240 in some areas. Don't think it'll matter very much.

Issues noted:

1) Scheduling sometimes fails
2) Car charges when not required at 6A.
3) Stop issues sometimes (restarts not long after).

I'm guessing this is the bug, where is says no power available, but has 6 available for one of the TWCs. If anyone wants to look, i'm not thinking it's explicit in the TWCmanager.py , I think it might be in the index.html where it is requesting info and waits 5 seconds, ( then has a few retries). Anyone else have thoughts on this? might just bee a poor handshake between the states.

 

[brkaus]

Honestly, I think a small load center with breakers is a better solution than a junction box with Polaris connectors or some such anyway. I do wonder if they are implying a more sophisticated load sharing config with their one example, like max 60a per WC, but a 100a budget overall, as an example. That would make a lot of sense.

I was going to use a small load center to share power instead of a junction box. Then I noticed/realized I only had two hots and a ground. Makes it questionable as the load center would only support 240v. Legal I think, but questionable.

 

[Myfirstone]

Is there a possibility too get only the I’d from the Tesla wall connector high voltage?

Is there same one that can make setup installer that ask for your green energy meter address and api key?

I’m not that stupid but unlikely it will not work for me too scroll true the whole script.