Twice during my last charging session today charging was stopped. I felt the UMC cable and the UMC adapter attached to the Tesla block and they were both hot to the touch. It’s hot here today, temps in the upper 80s. The charging cable appears to be properly seated. Any thoughts appreciated. NEMA 24-50 with a 50 amp breaker.
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davewill
Active Member
How hot? If you can't keep your hand on them, then it's too hot. If you can, then it's normal enough.
I can keep my hand on them. The issue was that charging was interrupted twice this evening. UMC is at the moment not plugged in, but the Tesla block into which the NEMA 14-50 is plugged is quite warm. There is no current going to the car. I’m beginning to suspect the wiring in the 14-50 outlet may be a bit loose. I have a spare UMC and 14-50 connector that I will swap tomorrow to see if I can isolate the problem. Thanks Dave.
I would turn off breaker, triple check that the receptacle is indeed de-energized, re-torque all conductor -> receptacle connections, visually inspect for overheating/discoloration on receptacle and wire insulation. If all checks out ok and the MC is still too hot, I would then manually reduce the charge amperage enough so that the the MC is functioning at just a warm temp and not a hot condition until I could exchange my MC for a new one.
I have found that ambiant temps can make a difference in hot climates and hot garages when charging at or near max rated rates such as 32a with a Gen II MC, 40a with a Gen I UMC, and 72 or 80a on a HPWC (I have no experience with the newer Gen WCs).
A professional licensed electrician may be your best approach.
Stay safe and good luck!
jebinc
Well-Known Member
It shouldn’t by that much. Mine was warm to the touch, on a NEMA 10-30 (24 amps), but never hot. Even when the ambient temperature was in the 80’s. I have since installed a HPWC and can charge up to 48amps. Used 4 AWG wire. Not even warm!
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If charging stops, there is a problem. I would turn off the breaker, take off the 14-50 receptacle face plate and inspect and retighten the wire screws. It could also be the 14-50 adapter or the Tesla EVSE box (what you call a block, I think), but less likely. Let us know what you find.
Thanks Cititad. Our problem is too similar to rule out high ambient temperature as a possible cause. Late yesterday when I plugged in for the night the ambient temperature in my garage was nearly 100. I’m gonna do scheduled charging until it cools off here. I will leave the garage door open too.
Thanks to all. I have a call in to my electrician. On this thread there are 2 of us with high ambient temperature as a common denominator. In the meantime I’m gonna schedule charging for early morning and leave the garage door open. I finished yesterday’s interrupted charging session just now. It’s much cooler this morning outside and in the garage. Everything was cool to the touch. The block was normal warm.
Waiting on a return call from my electrician.
Waiting on a return call from my electrician.
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jebinc
Well-Known Member
Good call, if you can, use 4 (or 3 even) gauge THHN wire. Keeps things nice and cooooool…
And safe too!Just for an extreme datapoint: it’s 111 degrees in my garage right now and charging at 32 amps while plugged in to 14-50 receptacle without any interruptions. Charger and cord are warmer than ambient but not so hot they can’t be held in hand.
Kleenerth3
Member
It's 3:17am and your electrician is due in an hour?! Holy crap.
I'd hate to see that bill.
jebinc makes a good point and an easy upgrade for the electrician to make when you get your second Tesla!
Good luck and keep us posted.
Thanks Kleen. 2 nights of charging with no issues. Electrician came at 7:30 yesterday morning and took apart the 14-50 outlet and couldn’t tighten the screws any more than they already were. No charge since he installed it. So I’m hoping that event was a one off. Yesterday and the day before it was still quite hot in the garage and when I left there was a low frequency hum coming from under the car. It went away after driving a mile or so. Is this battery cooling? Thanks again for your help.It's 3:17am and your electrician is due in an hour?! Holy crap.
I'd hate to see that bill.
jebinc makes a good point and an easy upgrade for the electrician to make when you get your second Tesla!
Good luck and keep us posted.
Kleenerth3
Member
Hey early bird! Good morning.
The car does cool the battery or warm up depending on the cycles. During those times, you might notice a slowing of charge rate and hear a fan, whir or even an occasional clunk. All's good!
Thanks for the update
Thanks Kleener. I thought it was battery cooling and as I said the hum goes away after I’ve driven a mile and park it. The other clunk I hear when I open the door and get in the car. Every time. Maybe something is engaging, contactors someone on another forum said? So far the car has been great. After the fact I learned that my July 2018 build is a production Hell car, probably built in the tent. Aside from a really small mis- aligned driver side door I can’t see or find any other defects. I haven’t ripped the car apart to find the electrical tape that holds everything together.Hey early bird! Good morning.
The car does cool the battery or warm up depending on the cycles. During those times, you might notice a slowing of charge rate and hear a fan, whir or even an occasional clunk. All's good!
Thanks for the update
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