Faulty HPWC or Breaker too Big?

[RamshakleZ]

My 2016 MS needed its onboard charger replaced (which they did under warranty). But, they also told me my HPWC might be faulty.

My HPWC is connected to a 100 amp breaker. But my car can only charge at a rate of 48 amp (60 amp breaker). Would it be better for me to change the breaker to 60 amps since too much power might be getting through? Or, it is impossible for that to be the problem and it truly could be a faulty HPWC?

 

[user212_nr]

You are contradicting yourself saying that you can "only" charge at 48A and on the other hand you think that too much power could be getting through.

48A sounds like a reasonable number to charge at for the Model S unless you paid extra for the ability to charge at 80A.

The 100A breaker is fine if it was done by a qualified electrician. Your car won't necessarily use all that.

 

[Chisale]

What do you have the internal maximum HPWC amperage dial set to? I'm assuming 48amp? I would doubt it's anything related to your breaker. Did Tesla offer any hints why they thought your HPWC might be bad? Maybe it's fluctuating the amperage rapidly which isn't good for any electronics and that could have possibly damaged your onboard transformer.

 

[TMeister]

My 2016 MS needed its onboard charger replaced (which they did under warranty). But, they also told me my HPWC might be faulty.

My HPWC is connected to a 100 amp breaker. But my car can only charge at a rate of 48 amp (60 amp breaker). Would it be better for me to change the breaker to 60 amps since too much power might be getting through? Or, it is impossible for that to be the problem and it truly could be a faulty HPWC?

So analogy... You plug your phone charger (uses less than 1/4 amp) into an outlet in your house than can supply 15 amps. Nothing interesting happens. The charger draws 1/4 amp.

It's the same thing for your car. Your car is drawing 48 A. Doesn't matter if the HPWC could supply 80 (which is implied having your HPWC on a 100A breaker), the car is only going to take 48. Circuit breakers are not a limiting device. They are an on-off switch that turns off after a sufficient amount of time at a load higher than their rating.

Now a different issue is that your car could have been built with 40A, 48A or 80A on-board charging. Depends on build date. If it is supposed to draw 80A then it should. What does your display say is the max when it is grayed out? That's the max your car can take.

 

[Lasttoy]

You cannot get 100amps out of breaker.your car is set for 48 amps by the factory. Newer car can take more. My antique takes 30 amps on home charger with 50amp breaker. If I plug onto 100 amps, my dual chargers will try for 60amps.

 

[Rocky_H]

You cannot get 100amps out of breaker.your car is set for 48 amps by the factory.

Yes, @RamshakleZ does have a car with the 48A onboard charger.

Other than that, most of your stuff isn't correct.

Newer car can take more.

No. Tesla stopped offering anything higher than 48A onboard chargers quite a while ago, at least a couple of years ago I think?

My antique takes 30 amps on home charger with 50amp breaker

Nope. You have an older car with the 1st gen UMC. It will draw 40A from that, which is the same level as the onboard charger in your car. The newer 2nd gen UMC can draw 32A.

If I plug onto 100 amps, my dual chargers will try for 60amps.

Nope. That would be 80A on that one.