Failed Mobile Connector and Teardown

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JWardell

TOO Master Member
Joined
May 9, 2016
Messages
4,213
Location
Boston
Country
Country
Tesla Owner
Model 3
#1
Toward the end of winter the button on my UMC stopped working for a while. Not a big deal then because the port was unlatched due to cold temps and you could press the door to open. A little more annoying above freezing as the port stayed latched so I had to start using the app to disengage.
Not long after temps above freezing though I had a few interrupted charges at random times, then a week later the UMC stopped working altogether.
The car started to report charge equipment problem when it was plugged in at this point, even if the UMC was unplugged from the wall.
Meanwhile, the LEDs on the UMC were always happy and green, never showing any of its many error codes.

Thankfully I have a second UMC (the failed unit is the one I bought ahead of delivery to keep plugged in at home) that came with the car, and that worked perfectly, so I knew the issue was only with the mobile connector and not the car. I contacted Tesla support, got a response after several days which deferred to mobile service, which then took several more days and insisted on scheduling a visit. Actually two for some reason. I eventually went through the details and convinced them to just send me a replacement instead, which took another 10 days to arrive.

The replacement worked perfectly, and after a few weeks of hearing nothing more from Tesla I figured it was safe to dispose of the old charger. Except my definition of electronics disposal is tear it open.

Here's a video I made of the teardown, noting how things work inside the UMC, and eventually finding the problem:


So as you can see I had water intrusion into the handle, frying the PCB for the button. Folks have debated before if these are weather resistant, but they HAVE to be. You can't sell a car that you can't fuel up just because it's raining for a week. And Tesla HAS gone through great lengths to seal everything here. Potting electronics is a mess and expensive and complex to manufacture, and they did so with this handle. I doubt the handle is any different in a wall connector or even a supercharger. But potting is prone to error so perhaps it didn't fill quite to the top (I would design the board lower or something). I really don't believe they would just rely on the weak adhesive under the label/button to seal out the elements.

The replacement being nearly a year newer did have a slightly part number and rev. 1101789-81-F (old) and 1101789-00-H (new) so perhaps they have corrected this or other issues.
 
Joined
Feb 1, 2019
Messages
11
Location
Southern CA
Country
Country
Tesla Owner
Model 3
#2
Thanks for the tear down and analysis.

Would be interesting to see if the weather sealing has improved in the later revision of the UMC. Also wondering if such improvement has been propagated to later version of the Wall Connector.
 

mswlogo

Top-Contributor
Joined
Oct 8, 2018
Messages
723
Location
MA
Country
Country
Tesla Owner
Model 3
#3
Thanks for the tear down and sharing.

I have two installations. One is indoors with a "Permanent" UMC. The Second is outdoors and uses a Wall Connector.
I don't know exactly how Tesla Rates these but I felt on day one the UMC is not really designed for permanent outdoor use and is the reason I went with the Wall Connector for the outdoor setup.
The Wall Connector is very rugged and I'd recommend the Wall Connector for any permanent charging setup, and mandatory for outdoor setups. That's just my own personal criteria.

In hindsight I plan to replace the "Permanent" UMC setup. I have the 2nd Wall Connector, I just have not had time to install yet.