Wall connector - Charge speed reduced

[masam]

I have a Tesla Wall connector (set to 72 amps) that I was using to charge a Model X P90D. The charge current was set to 72A. However after a short while (maybe a few minutes of charging), I got the "Charge speed reduced" message that you can see in the attached picture. The car is saying that it has detected an extension cord or faulty wiring. Has anyone else run into this issue ? The wall connector was installed by a licensed electrician.
Thanks!

 

[randy1077]

I have a Tesla Wall connector (set to 72 amps) that I was using to charge a Model X P90D. The charge current was set to 72A. However after a short while (maybe a few minutes of charging), I got the "Charge speed reduced" message that you can see in the attached picture. The car is saying that it has detected an extension cord or faulty wiring. Has anyone else run into this issue ? The wall connector was installed by a licensed electrician.
Thanks!

View attachment 193842

Sounds like you have undersized wire causing a voltage drop. I would use 3AWG copper for 80 amp breaker.

 

[masam]

Thanks ! Looks like I'll have to get the electrician to come back and redo this.

 

[FlatSix911]

Thanks ! Looks like I'll have to get the electrician to come back and redo this.

In the interim, I would suggest lowering the charge rate to 64 amps to avoid any issues

 

[TexasEV]

Sounds like you have undersized wire causing a voltage drop. I would use 3AWG copper for 80 amp breaker.

Charging at 72A would require minimum 90A breaker, not 80A.

 

[nuevodesi]

Charging at 72A would require minimum 90A breaker, not 80A.

That is correct. I just installed my wall charger for 72amp circuit with a 90amp breaker running #4/3 Copper. Check out the installation here.

 

[masam]

In the interim, I would suggest lowering the charge rate to 64 amps to avoid any issues

Absolutely ! While I have a 100amp breaker, I must admit I don't know what gauge wire they put in. I also had a NEMA 14-50 put in, so that will be the workhorse for now

 

[ig_epower]

I don't mean to thread jack but I have a wall charger set on a 40A circuit. I don't have reduced charging message issues but I don't need the fast charging - is setting to 30A not reduce the load on my circuits and also perhaps reduce the stress on my battery help matters? I figure the electrical costs would be similar to going at 40A?

 

[TexasEV]

I don't mean to thread jack but I have a wall charger set on a 40A circuit. I don't have reduced charging message issues but I don't need the fast charging - is setting to 30A not reduce the load on my circuits and also perhaps reduce the stress on my battery help matters? I figure the electrical costs would be similar to going at 40A?

If you have a 40A circuit the most you can charge at is 32A. Setting it for 30A isn't really reducing anything. Regardless, reducing the charging rate from 40 to 30A doesn't reduce the stress on the car. It's designed for the higher rates. You don't have to baby it.

 

[jbabb]

The picture shows a voltage of 220V when pulling 72A. What voltage does it show when only drawing a few amps? If the voltage starts out higher and drops very much as the current ramps up, the car detects that condition resulting in the message you see.
Have your electrician verify the gauge of the wire, and that all connections are tight. If the wiring is run a long distance, you may need a larger wire size to avoid the excess voltage drop.

 

[rypalmer]

The picture shows a voltage of 220V when pulling 72A. What voltage does it show when only drawing a few amps? If the voltage starts out higher and drops very much as the current ramps up, the car detects that condition resulting in the message you see.

This. It's the voltage drop that matters.

 

[masam]

The picture shows a voltage of 220V when pulling 72A. What voltage does it show when only drawing a few amps? If the voltage starts out higher and drops very much as the current ramps up, the car detects that condition resulting in the message you see.
Have your electrician verify the gauge of the wire, and that all connections are tight. If the wiring is run a long distance, you may need a larger wire size to avoid the excess voltage drop.

I didn't pay attention to the voltage when the car was first plugged in. I just had the car for an overnight test drive, so I'll have to wait for my car to be delivered before I can re-test. But, as you mentioned, there's a good chance that the wire length is the culprit. The run from the panel to the wall connector is over 100 ft. (not by choice).

 

[TexasEV]

I didn't pay attention to the voltage when the car was first plugged in. I just had the car for an overnight test drive, so I'll have to wait for my car to be delivered before I can re-test. But, as you mentioned, there's a good chance that the wire length is the culprit. The run from the panel to the wall connector is over 100 ft. (not by choice).

You've probably identified the problem, which may be remedied by heavier gauge wire.

 

[masam]

Thought I'd post an update here - the circuit was required with #3 wire but the problem persists. I'm now wondering if the service line coming in to the house is the culprit. While I can charge at 62 amps without issues I'd rather use the full 72 amp for a faster charge.

 

[OlavA]

For an 80' run I used #2 wire and get 238V at the car. In addition, I had the service increased to 200A into my house.

If you charge off peak household hours do you get the same result?

 

[CaliX]

Thought I'd post an update here - the circuit was required with #3 wire but the problem persists. I'm now wondering if the service line coming in to the house is the culprit. While I can charge at 62 amps without issues I'd rather use the full 72 amp for a faster charge.

I am in the same boat as you as mine drops down to 60 amp and I get the same message. My run is over 100' I have had it rechecked by another licensed electrician and Tesla checked all the logs on my X what they determined is it's the service coming into my house most likely the transformer. So I am now pressing my electric company to check the line and transformer.

 

[masam]

I am in the same boat as you as mine drops down to 60 amp and I get the same message. My run is over 100' I have had it rechecked by another licensed electrician and Tesla checked all the logs on my X what they determined is it's the service coming into my house most likely the transformer. So I am now pressing my electric company to check the line and transformer.

Definitely in the same boat. My run is also over 100'. I've requested the electric company to check the lines coming into the house.

 

[masam]

For an 80' run I used #2 wire and get 238V at the car. In addition, I had the service increased to 200A into my house.

If you charge off peak household hours do you get the same result?

I tried charging during off peak hours and it didn't help. I already have 200 amp service, so at this point I'm hoping the electric company can help with this

 

[OlavA]

View attachment 198642

I tried charging during off peak hours and it didn't help. I already have 200 amp service, so at this point I'm hoping the electric company can help with this

Probably a good idea.

They can check the voltage across the meter and go back from there.

I am getting a solid 241V from my meter.

 

[CaliX]

I tried charging during off peak hours and it didn't help. I already have 200 amp service, so at this point I'm hoping the electric company can help with this

I have 400 amp coming into my house with a 200 sub going out to my garage. My electric company is coming out to install a monitoring system to check and see if there is a 8% fluctuation that tesla says they see.

Call Charging installation inquiries or issues M-F 9-5:30 PM PST 650-681-6133 they have been very helpful and they continue to monitor my X and are giving me feedback. They say its the line and or the transformer.