How hot is UMC supposed to get?

[MattXowner]

sorry if this is a redundant post. Been charging nightly per manual and noticed 2 strange things and was hoping for help from the forum please.

1) UMC gets very hot to the touch. Not sure if this is normal or indicates a problem with the cable or my outlet.
2) car starts charging at 40 amps and then after about 1 hour drops to 36 amps

Is this normal? Still gets about 25 miles of ranger per hour but don't want my house to burn down.

 

[Gwgan]

Not normal. High resistance somewhere, at car port, at socket, on panel… Sounds like you’re charging from NEMA 14-50 on 50amp circuit. Is the wire size adequate to the socket from the panel? I don’t know what that size should be, only that for if it was a pre-existing socket for lesser needs it may be too small.

 

[CmdrThor]

If it is dropping the amps that is because it is sensing a problem. Being hot to the touch is also a problem. Check for loose connections on the circuit, bad outlet, bad mobile connector, etc.

 

[pchan]

sorry if this is a redundant post. Been charging nightly per manual and noticed 2 strange things and was hoping for help from the forum please.

1) UMC gets very hot to the touch. Not sure if this is normal or indicates a problem with the cable or my outlet.
2) car starts charging at 40 amps and then after about 1 hour drops to 36 amps

Is this normal? Still gets about 25 miles of ranger per hour but don't want my house to burn down.

You should have the service enter to check it out just for a peace of mind. Mine doesn't feel very hot to touch, but the cable and the unit itself are both warm. I do have some small amount of grease/oil leaking out from the unit the first couple times I used it. It is Tesla, I am sure the UMC must have some safety feature built-in to make sure it won't burn down the house. At the very least, there is a tiny red 'reset' button at the back. I would assume it is for user to reset the unit if it ever becomes a fireball.

 

[ecarfan]

The UMC can get warm in normal operation. I would not consider "hot" to be normal, but these are relative terms. One person's "warm" is another person's hot. And IR temp gun is useful in situations like that.

I suggest you go to your local Service Center, plug in to one of their HPWCs and see if your UMC feels the same to your touch as it does at home. Ask one of the service guys there to feel it.

 

[MattXowner]

Thanks everyone. I'm heading to the SC on Saturday. I'll be sure to bring the umc.

I had a new NEMA 14-50 installed. I hope it's an issue with the car or cable. Lol. Guessing it's easier to have Tesla fix it then the electrician. Lol.

 

[jsollender]

A similar line of questioning for this newbie...
Have a 3-car garage and kitchen remodel going on. The 2 door section is loaded with cabinetry, no car. My new 90D is sitting in 3rd stall. It was a hottish day in Denver, upper 80's. Don't remember the garage feeling too hot, but probably at end of day was low 80's in garage. I brought in my car, and charged it for very first time, starting at 3 pm. As 8 o'clock approached, went to garage and noticed it was far warmer than I would anticipate, and the charge cable (NEMA 14-50), pulling constant 40 Amp, 235 Volts was warm to the touch. Not too hot to hold, just a nice bathwater warm. So my question...
Does the whole car generate heat while charging? In other words will the battery pack get hot and radiate heat? How warm should the 8 foot charge cable be during charge cycle? Am I to be concerned?
I have my permit being pulled this week by the Tesla recommended installer, and was told last week before delivery that I can definitely use the charger. Thoughts?

 

[ecarfan]

Does the whole car generate heat while charging? In other words will the battery pack get hot and radiate heat? How warm should the 8 foot charge cable be during charge cycle? Am I to be concerned?

During charging the pack heats up, and the Tesla BMS (Battery Management System) regulates the pack temperature by circulating cooling fluid. That fluid of course has to be cooled down after passing through the pack, and the radiators and fans work together and warm air is blown out of the forward part of the car. You can feel it. That will warm up an enclosed garage. That is what you are feeling.

The charging cable will get warm. Nothing to be concerned about.

When you visit a Supercharger and charge the cable will also get warm.