Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Power consumption when heating and charging at 20A simultaneously

Neppaaja

Member
Mar 14, 2019
68
33
Finland
When I set the charging amps down to 20A from the max 24A on the center screen settings, does that only limit the charging power consumption or combined charging + cabin heating power consumption, i.e. the total power drawn from the Wall Connector?

I'm asking because at least I used to have problems with 25A circuit breakers (C25) tripping occasionally. After the first tripping I set the amps down to the 20A and after the second tripping one of the breakers was replaced just in case (it was not checked if it was defective). The Wall Connector is set to max (24A I think).
 

Ostrichsak

Active Member
Sep 6, 2018
3,503
3,546
Colorado, USA
When you manually set the amperage your limiting the amount the car will draw from that circuit. In most cases the car will also remember the location for next time she don't have to manually alter that setting.

It's very important though that you never have this set to more of what the circuit is designed for. 80% continuous-draw (like charging a Tesla) is the maximum safe amount a circuit can provide. Anything above that and the likelihood of excessive heat and potential fire hazard increases dramatically. So if your circuit is truly a 25 amp you don't want to exceed 20 amps from the setting in the menu ever.

Event then, if you have additional items on that circuit there's a chance he'll trip the breaker so it's important to know also what is currently using that circuit.
 
  • Like
Reactions: BlueOvalFan

Neppaaja

Member
Mar 14, 2019
68
33
Finland
When you manually set the amperage your limiting the amount the car will draw from that circuit. In most cases the car will also remember the location for next time she don't have to manually alter that setting.
Yes, she does remember the manually set amp setting.

It's very important though that you never have this set to more of what the circuit is designed for. 80% continuous-draw (like charging a Tesla) is the maximum safe amount a circuit can provide. Anything above that and the likelihood of excessive heat and potential fire hazard increases dramatically. So if your circuit is truly a 25 amp you don't want to exceed 20 amps from the setting in the menu ever.

Event then, if you have additional items on that circuit there's a chance he'll trip the breaker so it's important to know also what is currently using that circuit.
I think this 80% rule applies to a case where the whole power feeding system has max 25A capacity. I live in an apartment block and we have a separate unheated garage building having 12 individual garages. The garage building is fed by 3 x 63A connection. 3 x 25A automatic circuit breakers were installed in the same common electric cabinet, cable run to my garage and Wall Connector installed on the wall. Nothing else is connected to those 3 x 25A breakers. They are C25 type, C meaning normal "slow type". I think that in my case I should be able to utilise the full 100% power, i.e. 24A. I suspect that one of the C25 breakers was defective and that's replaced now, but I've left the setting to 20A just to be on the safe side.
 

Rocky_H

Well-Known Member
Feb 19, 2015
6,427
7,619
Boise, ID
I think that in my case I should be able to utilise the full 100% power, i.e. 24A.
Oh, it just clicked with me that I noticed you are in Finland. We were probably thinking U.S. without noticing that. I have read that is a specific difference with how most European wiring code is done versus North America. North America rates their circuits for short term current, but needs a derating factor for long term loads. I read that European standards does the rating of their breakers and wiring for a circuit to be full 100% continuous usage. So I think you may be right for what is should be able to do.
 

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