Nema 14-50 charge speed much lower than expected

[nwdiver]

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.

208v and 240v are wired identically. The only difference is that 240 has two hots 180 degrees out of phase and 208 has 2 hots 120 degrees out of phase. Both are ~120v L-N/G

 

[ucmndd]

Is your NEMA 14-50 adapter completely plugged in? Mine wasn’t and I got a lower charge rate.

The picture in the thread clearly shows the car is charging just fine at 207v/32a.

I think the AC/accessories being on is the best explanation. OP should see what the app reports while charging when the car is off and locked.

 

[Sagester]

Thanks guys, glad to have an explanation. I will try again later.

 

[lolder]

Turn your HVAC off to see the maximum rate. You can then turn it back on. When you exit the car the HVAC will turn off. Watching the voltage just before the charge starts to ramp up at 2 amps or so and comparing it to the voltage at 32 amps is a good test of the system. I get about a 3-4 v drop but about 1-2 v is at the master 150 a breaker. My 14-50 box was getting too warm so I opened it up and re-tightened the terminal screws ( with power off ). Now it's cool again.

 

[TexasEV]

This is normal for “0 miles added”. Your charging rate display of miles/hr will ramp up after a few minutes. Look at it again later.

 

[mswlogo]

This is normal for “0 miles added”. Your charging rate display of miles/hr will ramp up after a few minutes. Look at it again later.

Actually folks are right. Mine drops like 5 mph with HVAC and his 207 volts will lose another 4 mph. Waiting won’t help.

I know a few folks had issues with wall connectors and 3 phase. But I forget the details. But that does not sound like the case here.

 

[cwerdna]

208 volts is very common for commercial power in the US.

208 volts * 32 amps = 6,656 watts = 6.656 kW
240 volts * 32 amps = 7,680 watts = 7.68 kW

 

[mswlogo]

208v and 240v are wired identically. The only difference is that 240 has two hots 180 degrees out of phase and 208 has 2 hots 120 degrees out of phase. Both are ~120v L-N/G

This is the issue I thought might be occurring. It does not occur with the UMC though.

US Tesla Wall Connector + 3P3W 240V Delta power - FAIL

 

[hill]

I note that 208 in our area during heavy business usage, the public Chargers on 208 will occasionally get pulled down - as low as 202.
.

 

[IROAR]

ucmndd: Were would i see that information? the Charge screen shows that it is getting up to 32a and is at 207vView attachment 414782

I calculate 6.6k/hr using 32 amps and 206 volts. If your car gets 4 miles per kilowatt you are charging at 26.50 miles per hour, right?

 

[timk225]

Turn off the AC and do a 2 button screen reset and see what it says.

I've plugged into a local J1772 charger, and it'll show around 185 volts at 30 amps, still gets 21 mph.

 

[SigNC]

has to be the AC pulling down how much is going into the battery.