New Model 3 owner - What should I know?

[Colgate2004]

Hi all,

I just got my delivery date for my Model 3... Nov. 29!
This will be my first electric vehicle, so there is a lot for me to learn!

Based on my reading about charging I went ahead and installed a 240V 60A circuit in my garage (picture below)... at least for the immediate future I think I'll charge with the onboard charger (possibly upgrading to the Wall Connector later).

I just learned about how in the user interface you can set the charge cutoff to less than 100% capacity (say, 70, 80, 90%) for battery longevity purposes... that seems like a huge tip that I would never have thought of.

What other tips, tricks, or idiosyncrasies are there about this car that I should know about??

Looking forward to learning from folks who have more experience with these cars!

 

[TexasEV]

First thing you need to know is you can’t use a 60A circuit with the UMC. It looks like a 6-50 outlet in your picture. You can buy a 6-50 adapter for the UMC, but it needs to be on a 50A circuit, not 60A. If you had wired a 14-50 outlet, you could use the adapter that comes with the car, but again on a 50A circuit, not 60A.

Second thing you need to know is you’re ALWAYS using the onboard charger when charging with AC power. You’re either using the UMC (Universal Mobile Connector) or Wall Connector. Both are EVSEs, just one is fixed and can operate at higher amps, and one is plugged into an outlet.

Use the links on this page
Home Charging Installation
to find the installation instructions for 240V outlets and Wall Connector.

 

[Msjulie]

First thing you need to know is you can’t use a 60A circuit with the UMC

why?

 

[StellarRat]

First thing you need to know is you can’t use a 60A circuit with the UMC. Second thing you need to know is you’re ALWAYS using the onboard charger when charging with AC power. You’re either using the UMC (Universal Mobile Connector) or Wall Connector. Both are EVSEs, just one is fixed and can operate at higher amps, and one is plugged into an outlet.

Use the links on this page
Home Charging Installation
to find the installation instructions for both.

You need a Nema 14-50R plug, so you should have a 50 amp breaker not 60. Of course, if they put a 14-50 plug in with the 60 amp breaker the charger will work, but it won't be as safe. Either way you absolutely need the 14-50 plug to use the charger that come with car if you plan to use the full 32 amp charging capability.

 

[StellarRat]

why?

Because the breaker is not supposed to exceed power rating of the plug-in. That would allow the plug to overload without tripping the breaker.

 

[Msjulie]

Because the breaker is not supposed to exceed power rating of the plug-in. That would allow the plug to overload without tripping the breaker.

Ok so you were specifically talking about the outlet, in that it should not be under rated.

 

[StellarRat]

Ok so you were specifically talking about the outlet, in that it should not be under rated.

The breaker and the outlet should match in rating. If you have a 50 amp outlet you should have a 50 amp breaker. The 14-50R outlet is rated as being able to handle a 50 amp draw at 240v. If your breaker lets you exceed 50 amps then the outlet could overheat if something goes wrong and that could catch/cause a fire in the wall. With a matching breaker the breaker will trip if the outlet ever has more than a 50 amp draw put on it. That's pretty much all there is to it. If you're thinking you can just get a 60 amp outlet that won't work because the charger that comes with the car doesn't have the same prong layout. You'd have to get some kind of weird adapter. By the way, swapping a 60 amp breaker for a 50 amp breaker is a very simple job for any electrician. It's like 10 minutes of work. I did my own work at home and that part is super easy.

 

[TexasEV]

I think these questions demonstrate it’s not a DIY project. You don’t know what it is that you don’t know, and you installed something first and asked questions later. I think calling an electrician is in order. 240V circuits are not for amateurs.

 

[Colgate2004]

First thing you need to know is you can’t use a 60A circuit with the UMC. It looks like a 6-50 outlet in your picture. You can buy a 6-50 adapter for the UMC, but it needs to be on a 50A circuit, not 60A. If you had wired a 14-50 outlet, you could use the adapter that comes with the car, but again on a 50A circuit, not 60A.

Second thing you need to know is you’re ALWAYS using the onboard charger when charging with AC power. You’re either using the UMC (Universal Mobile Connector) or Wall Connector. Both are EVSEs, just one is fixed and can operate at higher amps, and one is plugged into an outlet.

Use the links on this page
Home Charging Installation
to find the installation instructions for 240V outlets and Wall Connector.

Hi TexasEV,

Thank you for the reply.
These are the two documents I was working off of:
https://www.tesla.com/sites/default...s/NEMA_6-50_installation_guide_NA_US_2017.pdf
Onboard Charger

As I understand it (please correct me if I'm wrong), the Model 3 LR's onboard charger runs at (up to) 48A. Yet the second page lists a 60A circuit for a Wall Connector installation (I can easily see the 48-60A difference as being due to inefficiency in the inverter).

I ran the circuit with 60A capacity (in both the wire gauge used as well as breaker installed in the panel) for purposes of future-proofing for a likely Wall Connector installation later. I understand the plug itself is rated at 50A not 60, so I suppose the NEC-compliant solution would be to swap the 60A breaker for a 50A breaker as long as I'm using the NEMA 6-50 plug, then when I get around to installing a Wall Connector, swap the 60A breaker back in its place. That way I'll be compliant with code and still getting the maximum charge speed out of both the UMC and WC.

Does that sound correct to you?
Thank you!

 

[TexasEV]

Either way you absolutely need the 14-50 plug to use the charger that come with car if you plan to use the full 32 amp charging capability.

Actually he could buy the UMC 6-50 adapter to use with that outlet and charge at 32A. After getting rid of the 60A circuit breaker, of course.

 

[Colgate2004]

Everyone, please do note that according to the second page I linked to above, while the Model 3 standard battery's onboard charger is rated for 32 amps, the long range battery's charger is rated higher, at 48 amps.

I'm merely going off of Tesla's documentation though... do folks perhaps have other information that contradicts this?

 

[TexasEV]

Hi TexasEV,

Thank you for the reply.
These are the two documents I was working off of:
https://www.tesla.com/sites/default...s/NEMA_6-50_installation_guide_NA_US_2017.pdf
Onboard Charger

As I understand it (please correct me if I'm wrong), the Model 3 LR's onboard charger runs at (up to) 48A. Yet the second page lists a 60A circuit for a Wall Connector installation (I can easily see the 48-60A difference as being due to inefficiency in the inverter).

I ran the circuit with 60A capacity (in both the wire gauge used as well as breaker installed in the panel) for purposes of future-proofing for a likely Wall Connector installation later. I understand the plug itself is rated at 50A not 60, so I suppose the NEC-compliant solution would be to swap the 60A breaker for a 50A breaker as long as I'm using the NEMA 6-50 plug, then when I get around to installing a Wall Connector, swap the 60A breaker back in its place. That way I'll be compliant with code and still getting the maximum charge speed out of both the UMC and WC.

Does that sound correct to you?
Thank you!

The first document you linked to says to use a 50A circuit breaker. As others have noted above, that’s for safety. So yes, switch out the breaker. Oversized circuit breakers aren’t safe (and aren’t code compliant for that reason). You will draw 32A on this using the 6-50 adapter which you will have to order from Tesla.

The reason you use a 60A breaker and wiring with the Wall Connector to draw 48A is you can only draw 80% of the load for continuous use such as car charging. Another way of saying that is the circuit has to be 125% of what you plan to draw continuously, so 60A for a 48A continuous draw.

 

[TexasEV]

Everyone, please do note that according to the second page I linked to above, while the Model 3 standard battery's onboard charger is rated for 32 amps, the long range battery's charger is rated higher, at 48 amps.

I'm merely going off of Tesla's documentation though... do folks perhaps have other information that contradicts this?

Irrelevant to this discussion. The UMC is limited to 32A. You can only draw 48A and use that full capability of the charger when using the Wall Connector (or a similarly rated J1772).

 

[Colgate2004]

The reason you use a 60A breaker and wiring with the Wall Connector to draw 48A is you can only draw 80% of the load for continuous use such as car charging. Another way of saying that is the circuit has to be 125% of what you plan to draw continuously, so 60A for a 48A continuous draw.

Ahh... the 80% rule. If I ever knew that one, I must have forgotten it!

At least I can take some solace in not being the only one confused by the 80% vs 100% ratings!
80% Breaker Rating Rule?
Overcurrent Protection and the NEC

Anyway, I'll swap out the 60A breaker for a 50A for as long as I'm using the plug, then if/when I upgrade to a Wall Connector I'll put the 60 back in.

 

[9erDog]

I would suggest making sure you have a good Wifi signal in the garage so that you can get software updates regularly.

 

[LyftupX]

Folks I was just going to
Update my dryer outlet until I found it was an actual 50 amp receptacle on a 30 amp breaker.

Ok so I know this is because it’s an older home folks used to have it wired for 50 but would change the breaker to 30 since the dryer is using it.

Anyone see a huge issue with this for temporary use. Making a adapter for the outlet and plugging in the Tesla but only drawing 24 amps , since that’s the breaker limit.

Will the Tesla stay at 24 Amps once I set it , despite the fact I will use the Tesla included adapter? I don’t want it seeing the adapter then ramping up the amps.

I will update my power in the Spring, 200 amp service when my Pop comes to town.

 

[TexasEV]

Folks I was just going to
Update my dryer outlet until I found it was an actual 50 amp receptacle on a 30 amp breaker.

Ok so I know this is because it’s an older home folks used to have it wired for 50 but would change the breaker to 30 since the dryer is using it.

Anyone see a huge issue with this for temporary use. Making a adapter for the outlet and plugging in the Tesla but only drawing 24 amps , since that’s the breaker limit.

Will the Tesla stay at 24 Amps once I set it , despite the fact I will use the Tesla included adapter? I don’t want it seeing the adapter then ramping up the amps.

I will update my power in the Spring, 200 amp service when my Pop comes to town.

You don’t need to make an adapter. Just buy the UMC 14-30 or 10-30 adapter, whichever you need. That will automatically set the amps at 24. You can buy an adapter for almost any outlet for $35:
Model S/X/3 Gen 2 NEMA Adapters

 

[brkaus]

Folks I was just going to
Update my dryer outlet until I found it was an actual 50 amp receptacle on a 30 amp breaker.

Ok so I know this is because it’s an older home folks used to have it wired for 50 but would change the breaker to 30 since the dryer is using it.

Anyone see a huge issue with this for temporary use. Making a adapter for the outlet and plugging in the Tesla but only drawing 24 amps , since that’s the breaker limit.

Will the Tesla stay at 24 Amps once I set it , despite the fact I will use the Tesla included adapter? I don’t want it seeing the adapter then ramping up the amps.

I will update my power in the Spring, 200 amp service when my Pop comes to town.

It should stay at 24a, but the car uses location to remember, so if some day the gps is confused it will go back to 40a.

People have also reported the setting getting cleared in occasion by firmware updates.

I’d just buy the proper adapter.

 

[LyftupX]

Got it , I’m leaving receptacle at 50... but make an adapter with additional 50 M plug and then 30 female then need Tesla 30 adapter.


If I used the setting I described previously , the 30 amp breaker would trip if working despite wiring being 50 amp and the car attempting 40a draw. But yes don’t want to chance that.

I see many online adapters still use the 50a male from Tesla but then shrink to 30a plugin. Don’t those pose the same risk as my first example? Forgetting the setting and attempting a 40a draw due to the Tesla adapter being used?

Thanks.

 

[brkaus]

Yes, those adapters do pose a risk. At one time, adapters from Tesla were limited and the supercharger deployment was not as good as it is today. A long distance trip required a bag of tricks. If you have no options and know the risk, go for it. But a proper adapter is cheap and much safer.

Why does it have a 30a breaker? What size are the wires?