What does the Wall Connector do exactly ?

[kimwin]

It's common knowledge that Wall Connector is the device standing between the circuit breaker (240V , N amps) and the battery charger inside the car.
The Wall Connector does not charge the car battery.
Does anyone know what else the Wall Connector exactly do during charging ?
From this forum, it seems like it monitor how many kWh are consumed for a charging session, (this value is slightly more than what the car reports)
Does it also monitor the current fluctuation, the wires temperature and automatically stops charging (or lower the charging current) to avoid an electrical catastrophe ?

 

[Kimmi]

I know it senses temperature. My three year-old generation three just started charging it 32 A instead of 40 that it was set for. Per Tesla I pulled the wall face off or the and looked at the wiring. There was no burning. Everything was tight, so they just sent a new one under warranty. I had read somewhere that about three years ago. A lot of the GEN threes were having problem. YMMV.

 

[GHammer]

The primary function is to communicate with the car and to only apply power to the plug once it has recieved a pilot signal from the car indicating it is ready for power. The wall unit also tells the car the maximum current it is able to deliver but the car is responsible regulating the current up to the maximum. The wall unit also protects itself by testing for a valid supply ground and monitoring temperature within the unit itself. The wall unit will also shut down power if the car pulls more than the maximun configured current. The car monitors for supply votage and current stability and drops the current as appropriate.

 

[kimwin]

GHammer,
thanks for your detailed explanations. My guesses are pretty closed, now confirmed.

 

[cwerdna]

Wall connector is basically a smart safety switch like other J1772 EVSEs except w/Tesla's proprietary connector (which Tesla only recently decided to refer to as NACS). See Basics of SAE J1772 and https://www.sae.org/binaries/content/assets/cm/content/standards/chargingprimer.pdf.

The pilot signal duty cycle tells the attached car how much it can draw at max and the attached car is supposed to comply. Otherwise, the vehicle would have no idea what's on the other end.

 

[Cosmacelf]

1. Safety, no power to car plug side unless it is plugged into and communicating with the car.
2. The Wall Connector tells the car how much current it can draw (was set during initial provisioning).
3. Load sharing, WCs can communicate to share power amongst themselves.

 

[Wattsisname]

I know it senses temperature. My three year-old generation three just started charging it 32 A instead of 40 that it was set for. Per Tesla I pulled the wall face off or the and looked at the wiring. There was no burning. Everything was tight, so they just sent a new one under warranty. I had read somewhere that about three years ago. A lot of the GEN threes were having problem. YMMV.

Mine was changed under warranty after 9 months.

 

[David29]

One other thing it does is to provide a sturdy and reliable cable and plug, presumably more suitable for daily long-term use than the Mobile Connector (no longer supplied with new cars but used by many early owners of Tesla cars). I say this in part because of my own experience with my WC, which is about 5 years old and is mounted outdoors, exposed to the elements and never has given a bit of trouble. (I also had an earlier one for 2 years that stopped working reliably, which Tesla replaced under warranty. )
Mine is not WiFi connected and cannot be chained together, so I think that makes it a Gen 1 or maybe Gen 2.
Finally, one reason I installed a WC rather than to use a cheaper device like an outlet, is that I live in a condo and had to convince my condo board that it would be safe to install this in the parking lot where it would be accessible to all and sundry. The fact that the cable would have no power in it unless it was actively charging, and that it had safety circuits that would disable it in case of ground faults, allowed me to make the argument that vandals or children or anyone else tampering with it would be very unlikely to be injured.
Plus, frankly it looks cool, with that green light that sequentially flashes as the car charges charges...!