Tesla Universal EVSE Connected, but 12V battery drained

There are 2 pilots, "pilot_low_v" and "pilot_high_v". "Pilot_high_v" is always changing from 0 to 12V, but "pilot_low_v" is not changing and stays around -12V all the time. Here is the graph with "pilot_low_v"

Screenshot 2024-04-28 132453 by alexsahka posted Apr 28, 2024 at 2:13 PM

 

What type of tool are you using to get these plots?

 

Tesla API > NodeRed > InfluxDB > Grafana

Tesla API: http://TUWC_ip/api/1/vitals

NodeRed: https://nodered.org

InfluxDB: https://www.influxdata.com

Grafana: https://grafana.com

Running in Docker Containers: https://www.docker.com

 

I would also like to check the resistance of the Tesla J1772 adapter, but unfortunately, there's no way to remove it from the handle or the charger itself.

 

How do you charge a Tesla with this then?
I thought the cable terminated in a NACS handle, and a provided J1772 adapter was used to connect to a non-Tesla.
When I watched the video, there was a clever way that the adapter stayed clipped into the box (when charging a Tesla), but it is a separate adapter that does come off of the NACS handle...

You could always check the resistance in-place (but be sure to disconnect the line power, by turning off the circuit breaker).

 

I thought about this as well, but the resistance measurement won't be accurate because the adapter is connected inside the TUWC.

 

It is pretty unlikely that the connection within the TUWC would affect the powered-off resistance reading.
Yes, it is possible for there to be an effect, but not likely at all since these resistances that you are measuring are pretty low.

 

Watch from 4:23 Tesla preventing removal of the magic dock connector due to theft?

 

OK, I see. The adapter does come off.. They just have a clever way to capture it when it is docked,
I'm sure it can be removed when not docked if you can find the right clip to press (or similar).

 

@MeNerdHair, I have finally completed the test you requested. To my surprise the Tesla adapter did beep in the continuity test. Here are the results. Sorry for my hand being in the way of the multi-meter
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Ha! I figured I would try to use paper (see video above) and it worked before I saw these posts

 

Can you share the process for removing a Tesla J1772 adapter from a NACS charging handle?

 

I wrapped a piece of paper around the NCS adapter before pushing the button on the J 1772 adapter to remove it. Once I got the 1772 adapter out, I was able to slide it off of the NACS connection.

 

Thanks!

 

let me know if you get it or not.

 

Yes, thanks! Here are the internal Tesla J1772 adapter schematics. There are no resistors or buttons present. I don't know if this is good or bad, but there's nothing to modify in the official Tesla to J1772 adapter.

 

Out of curiosity, I enabled "pilot_low_v" signal logging while the Clarity was connected with the official Tesla to J1772 adapter. The "pilot_low_v" signal shows spikes every minute or so. It seems like the TUWC is "fighting" the Honda Clarity after charging is complete.

Screenshot 2024-04-28 225354 by alexsahka posted Apr 28, 2024 at 10:54 PM

 

OK, now what you need to know is how the resistors / switch present themselves at the output of the NACS handle. Since the 1772 adapter just has straight-thru connections, it is apparently depending on those functions coming from the handle. I think you can measure the resistance looking back into the handle with the TUWC safely disconnected from the line. You can see if pressing the button on the handle affects the resistance.

If you don't see the resistors, then it is indeed possible that the NACS handle does not have the passive resistors, but simulates them actively when it is powered on. You don't want to be poking around there with power however so that may be the end of things that you can try.