Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register
  • We just completed a significant update, but we still have some fixes and adjustments to make, so please bear with us for the time being. Cheers!

50 amp service down to 32 amps

Stimyg

Member
Feb 17, 2013
80
0
New York
I just got my car and had a 14-50 put in with 50 amp service, which works out to 40 amps continuous. However today I noticed that while it runs at 40 amps for a while, pretty soon the car turns itself down to about 34 to 30 amps. What are some of the reasons this might be happening? And more to the point, what can I suggest to my electrician as to how to solve this?
 

wycolo

Active Member
May 16, 2012
3,068
422
WA & WY
Feel all adapter plugs, the charger & cord, and the plug going into the S. Nothing should be getting particularly warm to the touch. If you find a hot spot clean any nearby connection. If there is no connection near the hot spot then there could be a problem- call service. Some of the chargers have required replacement. Ditto with the 50A breaker; these should not be getting hot. Keep charger out of direct sun & ventilated as much as possible.

What is voltage shown on Charging Screen as the Amps decline?
--
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,024
1,013
I just got my car and had a 14-50 put in with 50 amp service, which works out to 40 amps continuous. However today I noticed that while it runs at 40 amps for a while, pretty soon the car turns itself down to about 34 to 30 amps. What are some of the reasons this might be happening? And more to the point, what can I suggest to my electrician as to how to solve this?

Temperature of the car and/or UMC can cause it to reduce power, as will the end of the charging cycle.
 

Stimyg

Member
Feb 17, 2013
80
0
New York
Ah that's interesting, in that it was a very hot and sunny day, and I do charge outdoors.

Any idea what part of the UMC should ideally be kept cooler? Or is it more the car? If I got the HPWC would that help any?

- - - Updated - - -

And about the voltage - I don't recall exactly and it moved around a bit, but I think in the 220s?
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,024
1,013
Any idea what part of the UMC should ideally be kept cooler? Or is it more the car? If I got the HPWC would that help any?

I believe it is more of the UMC "box" itself (the contactor/ground fault/interlock circuitry).
 

brianman

Burrito Founder
Nov 10, 2011
17,515
2,980
I just got my car and had a 14-50 put in with 50 amp service, which works out to 40 amps continuous. However today I noticed that while it runs at 40 amps for a while, pretty soon the car turns itself down to about 34 to 30 amps. What are some of the reasons this might be happening? And more to the point, what can I suggest to my electrician as to how to solve this?
Just to cover our bases...

1. Do you have the dual chargers option?
2. When it drops to 34 or 30 A, what is your SOC (state of charge)?
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,024
1,013
But would the car lower its maximum attempted charging rate? Ie it was showing 32/32, not 32/40.

It lowers the "/xx" when you crank down the charging current, or when the plug isn't fully inserted, or when the car needs to reduce its maximum charge current due to temperature. You may need to attempt to press the up-arrow to attempt raising the charge current again.
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top