Is it normal for the wall connector cable to get hot @80 amps?

[BrettS]

I just picked up my new (to me) 2015 Model S with dual chargers. I also finished installing my wall connector on a 100 amp circuit and set it to charge at 80 amps. After 2 hours of charging the cable between the wall connector and the car was getting pretty hot. Almost too hot to comfortably hold, especially in the first 2 or 3 feet closest to the charger.

I know 80 amps is the top end for that charger, but I'm wondering if it's normal for the cable to get that hot.

Thanks

 

[365gtb4]

Not normal. I have two HPWC charging at 80A and they will get warm but never hot. I would get an infrared thermometer and measure the temperature along the cable and at each end and see what's going on. Until the issues is resolved I would reduce the amperage to maybe 40 amps.

 

[BrettS]

Ok, thanks. I guess that's a bit of a concern then. I'm in florida and it was pretty warm today. Probably close to 90. The charger is in the garage, but I'm not sure it was really much cooler in the garage anyway. I'm sure the high ambient temp didn't help

 

[Rodolfo Paiz]

It does get somewhat hot. As for how hot is OK, you may want to check with your Tesla local service people. It's never bothered me.

Also, remember that your battery can handle 80A and supercharging, but it'll live longer and age more gracefully if you charge more slowly. Also, lithium-ion batteries are happiest (and age best) when they spend as little time as possible either full or empty. If you use 50% of the battery on a day with lots of driving, for example, you may want to charge only to 80% so your use of the battery ranges from 30% when you come home to 80% the next morning.

Since I rarely needed more than 100 miles in a day, for example, I charged my Model S to 75%, giving me rated range of 195 miles. I'd come back home with 75-100 miles of rated range left in the very worst days (about 30% to 40%), and I've charge overnight at 20A/240V so it would take 5-6 hours to recharge back to 195. Lastly, every month or two, I'd do a full charge to 100% so the pack would "balance" itself.

I was never ever stressed for lack of range, and after four years my battery still held 98% of its original range. Anecdotal yes, but based on good science. Make sure you aren't living with range anxiety, there's no need for that. But while keeping enough range so you always have a great reserve, charging to a lower maximum will keep your battery healthier over time. You don't have to do any of this, but you have the choice if you want to baby your car and keep it in the best possible shape.

 

[AmpedRealtor]

It will get "very warm" at the vehicle connector side and the cable will be quite warm to the touch as well. This is normal. However, if it feels like you are going to scald yourself and get that instinctive reaction to let go or get burned, then I would recommend contacting service to get your charge cord replaced. I've had mine replaced 3 times in the last 4 years. It wasn't until the last replacement about 2 years ago when it actually felt like I wasn't going to burn myself.

 

[tga]

Also, remember that your battery can handle 80A and supercharging, but it'll live longer and age more gracefully if you charge more slowly.

There's lots of discussion here about recent studies that show that faster charging is no where near as bad as originally thought, and may actually be beneficial.

20kW charging (80A @ 240V), while large in absolute terms, is not all that fast relatively speaking (0.25C for an 85kW battery). Not really worth worrying about from a battery health standpoint. Although charging slower will be easier on your utility, electric system, HPWC/UMC, chargers, etc (mainly due to less heat).

 

[BrettS]

It will get "very warm" at the vehicle connector side and the cable will be quite warm to the touch as well. This is normal. However, if it feels like you are going to scald yourself and get that instinctive reaction to let go or get burned, then I would recommend contacting service to get your charge cord replaced. I've had mine replaced 3 times in the last 4 years. It wasn't until the last replacement about 2 years ago when it actually felt like I wasn't going to burn myself.

Thanks. I don't think it got quite to that point. I could hold it, but it wasn't really comfortable to do so. I think for now I'll keep an eye on it and see how it does on a cooler day. Then again, we're heading into summer and there are going to be a lot more warmer days ahead.

 

[LoL Rick]

I usually follow the advice from Cottonwood below and set my charge rate to 56 amps at home. I bump it up if needed, but for everyday use this is fast enough and reduces the stress on the components.

Question on power distribution using dual chargers at >40 amps charging current.

 

[animorph]

If the cable temperature is only high at the HWPC end I would check the connection to the HWPC. Hotter at the car could be a poor connection there.

 

[clarksw]

I have a problem during charging. I'm using the NEMA 14-50 Gen2 mobile connector and last week I received an alert that charging had been disrupted while charging in my garage. I went to check and the mobile connector was very hot and the circuit breaker was very very hot. I called the electrician that put in the NEMA 14-50 outlet and he tested it and said everything was in order and thought it was a problem with the mobile charger. I took the mobile charger back to Tesla today and they charged a Tesla for 4-5 hours and did not duplicate the problem. I'm not sure what to do at this point!!!!

 

[Helmuth]

There's lots of discussion here about recent studies that show that faster charging is no where near as bad as originally thought, and may actually be beneficial.

Totally agree. After 53,000 miles driven (MX 100D) in 8 months, use the Supercharger every day once and charging at 48 Amp every night at home (always to 90%) I lost only 0.28 miles so far!

 

[BestHand]

I have a problem during charging. I'm using the NEMA 14-50 Gen2 mobile connector and last week I received an alert that charging had been disrupted while charging in my garage. I went to check and the mobile connector was very hot and the circuit breaker was very very hot. I called the electrician that put in the NEMA 14-50 outlet and he tested it and said everything was in order and thought it was a problem with the mobile charger. I took the mobile charger back to Tesla today and they charged a Tesla for 4-5 hours and did not duplicate the problem. I'm not sure what to do at this point!!!!

Circuit breaker should not be hot. If it is hot it can be a few couple reasons: bad contact between a wire and a breaker (wire is not tighten enough), bad contact between breaker and rail, or bad contacts in a breaker switch. At first check if terminals tighten enough. If wire ends looks fine, not burned, and terminals tight, I would try to replace breaker and see.

 

[Snowstorm]

I charge at 72A at work and the cable does get warm, but never burn your hand hot.Ambient around 26c

 

[tga]

I have a problem during charging. I'm using the NEMA 14-50 Gen2 mobile connector and last week I received an alert that charging had been disrupted while charging in my garage. I went to check and the mobile connector was very hot and the circuit breaker was very very hot. I called the electrician that put in the NEMA 14-50 outlet and he tested it and said everything was in order and thought it was a problem with the mobile charger. I took the mobile charger back to Tesla today and they charged a Tesla for 4-5 hours and did not duplicate the problem. I'm not sure what to do at this point!!!!

How long have you been using this setup? Is this a new problem? What amperage are you charging at? The breaker should get warm (~100F, maybe a little more), but not hot.

 

[clarksw]

I received my model X in late June of this year and have been charging since July every night. This is the first time it has happened. I'm charging at 32 amps. The breaker seemed to be hotter than 100 but again what happened was that I received a message from my Tesla app that the charging had been disrupted and that is when I noticed the breaker was very hot. Any advise or ideas would be most appreciated. Thanks!!

 

[tga]

What part of the UMC was hot? The handle at the car, the plug, the box in the middle?
What is the breaker rating? 40A or 50A?
I would start charging and monitor the voltage displayed by the car as the current ramps up from 0 to 32. You shouldn't see a drop of more than a few volts (less than 10). If more than that, there's a high resistance connection somewhere causing the drop, which will result in heating. When the car sees this, it will drop the charge current to a safer level (although I've never seen it stop completely).

If there is a significant drop in voltage, that's something the electrician can trace down. How did he rest the outlet? Under load (while the car is charging)? Just checking the voltage at the outlet without putting it under load doesn't really show anything.

 

[BestHand]

What part of the UMC was hot? The handle at the car, the plug, the box in the middle?
What is the breaker rating? 40A or 50A?
I would start charging and monitor the voltage displayed by the car as the current ramps up from 0 to 32. You shouldn't see a drop of more than a few volts (less than 10). If more than that, there's a high resistance connection somewhere causing the drop, which will result in heating. When the car sees this, it will drop the charge current to a safer level (although I've never seen it stop completely).

If there is a significant drop in voltage, that's something the electrician can trace down. How did he rest the outlet? Under load (while the car is charging)? Just checking the voltage at the outlet without putting it under load doesn't really show anything.

To check how voltage drops is a great idea, forgot about it.

 

[davewill]

I have a problem during charging. I'm using the NEMA 14-50 Gen2 mobile connector and last week I received an alert that charging had been disrupted while charging in my garage. I went to check and the mobile connector was very hot and the circuit breaker was very very hot. I called the electrician that put in the NEMA 14-50 outlet and he tested it and said everything was in order and thought it was a problem with the mobile charger. I took the mobile charger back to Tesla today and they charged a Tesla for 4-5 hours and did not duplicate the problem. I'm not sure what to do at this point!!!!

You need a new electrician. How can the charger make the circuit breaker hot? If the car is pulling too much current the breaker should trip before it gets hot. There's obviously a big problem with the connections, not the car and EVSE.

 

[BestHand]

The circuit breaker has a switch inside. If switch contact is bad it can get very hot even when current is below the shut off level. Gotta check all connections and if they are tight change the breaker.

 

[clarksw]

What part of the UMC was hot? The handle at the car, the plug, the box in the middle?
What is the breaker rating? 40A or 50A?
I would start charging and monitor the voltage displayed by the car as the current ramps up from 0 to 32. You shouldn't see a drop of more than a few volts (less than 10). If more than that, there's a high resistance connection somewhere causing the drop, which will result in heating. When the car sees this, it will drop the charge current to a safer level (although I've never seen it stop completely).

If there is a significant drop in voltage, that's something the electrician can trace down. How did he rest the outlet? Under load (while the car is charging)? Just checking the voltage at the outlet without putting it under load doesn't really show anything.

Mostly the box in the middle and the plug got hot on the UMC. I monitored the voltage displayed as the current ramped from 0 to 32 and it went from 240 to around 234. I don't think he reset the outlet under load.