Model Charger now working correct (software fix?)

[MSullivan]

Sorry title is wrong, Mobile Charger now working.

My refreshed 75D has been unable to charge at it's full amperage capability since I received it (at home anyway).
I have it on a 40 amp breaker and set it up at 32 amps. Every time I used it the Model S would say something is wrong with my wiring and throttle it back to 30 amps.
I am heading in for snow tire changeover next week and thought I would bring the charger in to be looked at.
Well since the latest 8.0 update I am able to charge at 32 amps no problem, in fact I tested it at 34 amps for a few minutes with no problems.
Maybe it is a coincidence, especially since I haven't seen a lot of similar complaints.
I thought it might be my power but I have solar panels and during mid day when I am off the grid it would still throttle down.

 

[MSullivan]

Disregard, spoke too soon.
After working great it is back to going down to 30 amps.
False alarm.

 

[Rocky_H]

Sorry title is wrong, Mobile Charger now working.

My refreshed 75D has been unable to charge at it's full amperage capability since I received it (at home anyway).
I have it on a 40 amp breaker and set it up at 32 amps. Every time I used it the Model S would say something is wrong with my wiring and throttle it back to 30 amps.

Wait a second. I think I see the obvious problem here. You say it is your MOBILE charger, but you have it set up on a 40A breaker? What I notice completely missing here is what kind of actual OUTLET you have installed that the mobile charge cable (UMC) is plugged into. Since there is no 40A outlet type, what in the world kind of outlet do you have there? Since the UMC is intended to plug into a 14-50 outlet, that is probably it, right? If so, that is a blatantly wrong and illegal installation that violates electric code. By the way, that is why the car keeps lowering down the current to 30. It thinks it is a 50A circuit and detecting resistance problems because the wiring is not as thick as it needs to be.

A 14-50 outlet is a 50 amp outlet and NEEDS to be on a 50 amp breaker with 6 guage copper wiring. That 40 amp breaker is wrong, and I don't know what wire size you have, but since an electrician mistakenly wired it as a 40A circuit, it probably has undersized 8 gauge wiring, too.
The installation guide from Tesla for the 14-50 outlet is here, which you and an electrician can consult.
https://www.tesla.com/sites/default/files/downloads/US/universalmobileconnector_nema_14-50.pdf

To fix this, you have a couple of options. You can't keep using the 14-50 outlet on the 50A circuit. You can either fix the circuit to be a legitimate 50A circuit that passes code, or you can treat it as a 40A circuit, and replace the outlet with some kind of wall charging unit, so that it is actually set for a 40A circuit and provides 32 or less amps to the car.