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Nema 14-50 charge speed much lower than expected

I recently picked up a Dual motor M3, with the intention to charge in my building's garage on a Nema 14-50 plug they installed for me. I am getting a charge rate of a about 15miles/hour at 32 amps. Is this normal? I thought A nema 14-50 connection was supposed to provide yoou with about 30 miles per hour in range?

Am I doing something incorrectly? Thank you.
 

ucmndd

Well-Known Member
Mar 10, 2016
9,074
17,597
California
I recently picked up a Dual motor M3, with the intention to charge in my building's garage on a Nema 14-50 plug they installed for me. I am getting a charge rate of a about 15miles/hour at 32 amps. Is this normal? I thought A nema 14-50 connection was supposed to provide yoou with about 30 miles per hour in range?

Am I doing something incorrectly? Thank you.

What is the reported voltage and power (in kilowatts) when the car is charging? Almost sounds like you’re missing a leg and charging at 120 volts.
 
Building on that second question about voltage, since you mention you're charging in your "building" it seems you might live in a larger apartment building that is served with 3 phase power, so your outlet would be providing 208V instead of 240, and your charge rate would be accordingly lower. There's really not much you can do about it short of getting the building to install a special transformer just for you - highly unlikely and probably prohibitively expensive.
 

ucmndd

Well-Known Member
Mar 10, 2016
9,074
17,597
California
Building on that second question about voltage, since you mention you're charging in your "building" it seems you might live in a larger apartment building that is served with 3 phase power, so your outlet would be providing 208V instead of 240, and your charge rate would be accordingly lower. There's really not much you can do about it short of getting the building to install a special transformer just for you - highly unlikely and probably prohibitively expensive.

I thought about 208 vs 240, but that’s only a ~1kw difference at 32 amps, so I’d expect to see the car report ~25 miles per hour vs. 30. 15 is too low for that to be it.
 
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ucmndd: Were would i see that information? the Charge screen shows that it is getting up to 32a and is at 207v
20190602_142918.jpg
 

ucmndd

Well-Known Member
Mar 10, 2016
9,074
17,597
California
ucmndd: Were would i see that information? the Charge screen shows that it is getting up to 32a and is at 207vView attachment 414782

That’s weird.

I notice it says “0 miles added”, as if you just started a charge. Does it stay at 15 miles/hr for the duration of the charge?

32 amps at 208v is ~6.6 kw, which is about 24-25 miles per hour of added range on your model 3.

Note the time remaining is accurate - about 3.75 hours to add another 90 miles to get you to 90% at 25 miles/hour. So the “15 miles/hr” the car is displaying is just... wrong.
 
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Uncle Paul

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Nov 1, 2013
6,299
7,645
Canyon Lake,CA
To get the full rated NEMA 14/50 charge you should be drawing from a 50 amp circuit and being fed 240 Volts. Less than that will give you a slower charge. A 50 amp circuit can only legally give you 40 amps maximum for continous use like charging an EV.

Maybe you could find another place (Service Center) to plug it in and see what you could get with a proper feed.
 
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ucmndd

Well-Known Member
Mar 10, 2016
9,074
17,597
California
To get the full rated NEMA 14/50 charge you should be drawing from a 50 amp circuit and being fed 240 Volts. Less than that will give you a slower charge. A 50 amp circuit can only legally give you 40 amps maximum for continous use like charging an EV.

Maybe you could find another place (Service Center) to plug it in and see what you could get with a proper feed.

Good info, unfortunately it’s irrelevant to anything posted in this thread thus far.
 
I was at a L2 public charger last weekend and was charging at 208v @ 32amps. I got about 110 miles of charge in 4 hours. I noticed, however, when I got into the car to cool it down (It was 98F outside, 110F in the car), my charge rate with the AC on and set to 4 fan speed went to about 10mph. Full fan (speed 10) put the car at 1mph charge.

Do you have any accessories on? Fan, AC, heat (not likely I know).
 

nwdiver

Well-Known Member
Feb 17, 2013
8,989
13,318
United States
I was at a L2 public charger last weekend and was charging at 208v @ 32amps. I got about 110 miles of charge in 4 hours. I noticed, however, when I got into the car to cool it down (It was 98F outside, 110F in the car), my charge rate with the AC on and set to 4 fan speed went to about 10mph. Full fan (speed 10) put the car at 1mph charge.

Do you have any accessories on? Fan, AC, heat (not likely I know).

Good catch; Looks like his AC is on.
 

mswlogo

Well-Known Member
Aug 27, 2018
8,248
7,751
MA, NH
I think I know what’s wrong. It’s come up a few times.

The Tesla Wall Connectors are designed for residential 240V split phase. Even though neither the UMC nor Wall Connector require Neutral they both test to see 120V is present between hot and ground (or neutral).

This sounds like a commercial building with 3 phase which won’t get 120V to ground and has no neutral.

There are adapters you can get I think. But not cheap to my understanding.

Technically you don’t have a 14-50 outlet. Because you have no Neutral.
 

ucmndd

Well-Known Member
Mar 10, 2016
9,074
17,597
California
I was at a L2 public charger last weekend and was charging at 208v @ 32amps. I got about 110 miles of charge in 4 hours. I noticed, however, when I got into the car to cool it down (It was 98F outside, 110F in the car), my charge rate with the AC on and set to 4 fan speed went to about 10mph. Full fan (speed 10) put the car at 1mph charge.

Do you have any accessories on? Fan, AC, heat (not likely I know).

Great point. I imagine the AC, cabin fan, and other accessories could easily consume ~2kw when running, which obviously reduces the amount of energy going into the battery.
 
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