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Home charging 40 amps to 48 amps

Home charging 40 amps to 48 amps

I just bought my MX after selling my MS. My MS charged at a maximum rate of 40 amps. When I got my MX I noticed I could charge at 48 amps but did not have time to change the 50 amp breaker to a 60 amp breaker till today, 2 weeks later. Everytime I try to change the amp draw to 48 amps MX changes it to 40 amps. I can only assume it is doing this bc of the GPS recognition feature. How do I change it so the vehicle will charge at 48 amps at my home? Do I need to do a factory reset? Has anyone else had this issue? I've tried resetting by pressing the 2 wheels on the steering wheel with zero success.
Thank you for your input.

JAnnen | 03. Juni 2017

Your HPWC is set to 40A. If you change the HPWC DIP switches to 48A, the car will charge at 48A, HOWEVER: you should verify that the whole circuit is safe at 60A before changing the DIP switches.

You could have the original installer update the circuit. House fires are nasty. Be safe.

lou.secco | 03. Juni 2017

I have 6 AGW and 60 amp breakers. I'm good to go. What is HPWC DIP switches?

Uncle Paul | 03. Juni 2017

Is there a significant benefit to you with charging at the faster rate.

Slower charging is better for the car.

lou.secco | 03. Juni 2017

Just trying to maximize efficiency and learn about the car.

speyerj | 03. Juni 2017

The DIP switches are little binary switches within the HPWC that tell it how high to go in amperage.

At higher amperage yes you'll gain some extra miles per hour, but the real question is whether that matters at all based on your driving patterns. There seem to be a lot of different answers, even from Tesla staff as to whether faster/slower charging matters in the long term for battery health. Certainly nothing you can do at home approaches a SC, so maybe it doesn't even matter (on the battery level all the batteries ever see is DC, even if it enters the inverter as AC from your HPWC the batteries just perceive low flow DC coming in...much less DC than the SC feeds them)

lou.secco | 03. Juni 2017

The cable that comes with the MX is limited to 40 amps and MX knows that. Thank you for your help. I needed a magnifying glass to read it.

poloX | 04. Juni 2017

UNLESS you upgraded your X to have the on board 72A charger, how is that possible??? Your X can only charge 40A max unless there is external higher Ampare DC charger such as at the SC stations.

PedanticOne | 04. Juni 2017

Why are you saying that, polo? The base charger does 48A. That's what mine is, and that's what my HPWC is set to, and that's what it tells me it's charging at after it's plugged in.

Redmiata98 | 04. Juni 2017

Shorts, which "cable" is limited to 40 amps?

PedanticOne | 04. Juni 2017

The UMC that comes with the car.

lou.secco | 04. Juni 2017

The cable that came with the car.

Redmiata98 | 04. Juni 2017

Got it, the UMC IS 40 but the HPWC can put out 48.

poloX | 04. Juni 2017

sorry, I meant the combo and is limited by the cable.

Rocky_H | 06. Juni 2017

@shortscaptain, Wow, I notice a few things going on that it is taking a while for people to catch on to.

First off, you never even gave any hint at first at what type of charging setup you have. Are you using a wall connector? Mobile charge cable with an outlet?, etc. etc.

People were misled into thinking your setup was a wall connector because you mentioned changing out the breaker from a 50A to 60A. No one even considered that could be using the mobile cable and an outlet, because that would be an electric code violation. The mobile charge cable goes to a 14-50 outlet type. A 14-50 outlet type generally uses a 50A breaker (or a 40 in some exception circumstances). It is NEVER, under any circumstances, allowed to have a 60A breaker on it. That is illegal.

So yes, the mobile charge cable can only plug into outlets that are rated up to 50A, and it will only draw up to 80% of that level, so 40A maximum. You can't get 48A through that cable. You would need to replace the outlet with a wall connector and have the proper wire gauge to support a 60A rated circuit, drawing 48A.

dortor | 06. Juni 2017

I'm surprised people are still spouting garbage regarding what the cars can charge at:

All Tesla Model X's are capable of charging at 48 amps (if what your plugged into will provide that much power)
You can upgrade the chargers to charge at 72 amps

The Universal Mobile Charger than comes with the car can only charge at a maximum rate of 40 amps as that is all the UMC will ever provide.

Tesla's HPWC or the new Wall Mounted Chargers can charge at any rate from 20 - 80 amps, but must be installed with appropriate circuit breakers and wire to match the charge rate you desire.

If you plug in a 72 AMP Model X into a 32 amp Wall charger it will charge at 32 amps - since that is all the power the charger provides

If you plug a 48 AMP Model X into an 80 amp Wall charger it will charge at 48 amps since that is all the car can handle.

if you plug a 72 AMP Model X into a UMC with a NEMA 14-50 connect it will charge at 40 amps - since that is all the UMC can provide

If you plug a 72 AMP Model X into a UMC with a NEMA 5-15 plug - it will charge at about 12 AMP's @ 110 volts since that is all the UMC will provide.

When asking why does my car only charge at "X" rate we need to know a few things

What charger configuration do you have installed in your car?
Are you Using an UMC or a hard wired wall connector?
If you're using a Wall connector what breaker/wire was it setup with? And what setting has been set inside the Wall connector?
If you're using a UMC what plug do you have on the end of the UMC and what type of plug is it plugged into?

Older Tesla Model's S used to come with 40 amp (not 48, 40) chargers as standard, and you could upgrade to dual chargers which would charge at up to 80 amps (if the charging you're plugged into will provide that much power).

So the possible Configurations are as follows for Maximum charge rates on all Tesla Cars

Model S - 40 amps (no longer manufactured)
Model S - 80 amps (no longer manufactured)

newer Model S - 48 amps
newer Model S - 72 amps

Model X - 48 amps
Model X - 72 amps

chargers can provide anywhere from 1 amp to 80 amps - and the car adjust based on what it sees and what charger configuration you have on the car.

lilbean | 06. Juni 2017

That's a good summary.

shaia8 | 19. August 2017

Why can't I use a Wall Connector pushing 72 AMPS to charge my 90D Model X? Tesla sales guy said the Model X 90D can ONLY handle a maximum of 48 AMPS. What happens if I purchase the Wall Connector and push 72 AMPS out?

shaia8 | 19. August 2017

Never mind I just read your answer

Redmiata98 | 20. August 2017

Was the change from 80 to 78 actually mandated by a new restriction in Canada? If not, why did it drop 2? Must be some logical answer that the assembled brain power can answer.

packpike | 29. August 2017

I don't see where the 72amp option exists any more in configuring an X, but maybe I'm missing it. Is it rolled into the P upgrade or somewhere else, or was the upgrade recently made standard across the board?

ratchet | 29. August 2017

I took delivery of my MX 100D near the end of April this year. It was during the week when they included the Hi Amp charger at no extra cost (it was still available at extra cost for the 75D). The following week, they bumped the price up a bit and changed options to show the Hi Amp charger being standard on the 100D. They have since deleted all reference to the charging rate of the vehicle but have notes on their Charging Calculator near the bottom of the Model X page to cover a Tesla Wall Connector on a 60 amp circuit (providing 48 amp charge rate) and 90 amp circuit (providing 72 amp charge rate). There are not exceptions that would indicate some vehicles cannot charge at either rate so I am assuming that they install the 72 amp charger in all Model X's now.

rsteele888 | 31. August 2017

In May of 2017 I considered a 2016 X 75D which had a 48A internal charger. I was told that I could upgrade the hardware to 72A (I forget the price and don't know if this option is currently available). Instead I bought a 2017 X 100D that came standard with 72A. I installed a 200A service and dedicated 100A to a Wall Connector capable of daisy chaining to simultaneously charge an X & T3. No T3 yet but I love the ease and flexibility of the Wall Connect. The car is pretty nice too.

rsteele888 | 31. August 2017

In May of 2017 I considered a 2016 X 75D which had a 48A internal charger. I was told that I could upgrade the hardware to 72A (I forget the price and don't know if this option is currently available). Instead I bought a 2017 X 100D that came standard with 72A. I installed a 200A service and dedicated 100A to a Wall Connector capable of daisy chaining to simultaneously charge an X & T3. No T3 yet but I love the ease and flexibility of the Wall Connect. The car is pretty nice too.

Starlifter | 31. August 2017

I want a SC in my garage. Elon should get moving on that.......:-)

Triggerplz | 31. August 2017

@Starlifter a SC in your garage? Santa got one!! https://youtu.be/6nRO9RkWasQ :-)

Triggerplz | 31. August 2017

By The Way if you have 6 Tesla's Tesla will install a supercharger at your house

eric | 04. Mai 2018

Back to the original posters comment about swapping the breaker from 50 to 60 amps:

That is a dangerous and bad idea to do on a NEMA 14-50 plug (the 50 meaning it is capable of 50 amps).

But if they did have a HPWC (which it sounds like they did NOT) then YES, in some circumstances you could swap from a 50 amp breaker to a 60 amp breaker and change the rotary dial (it is a dial at least on the new units) to allow for charging at up to 48 amps. I just yesterday finished installing my HPWC for my soon-to-ship Model 3 and I did it on 6 AWG on a 60 amp breaker.

HOWEVER - AND THIS IS A BIG HOWEVER - #6 AWG is only rated for 60 amps IF it is 75 degree C rated wire and connected to devices on both ends that are rated for 75 degrees C. If your installer used NM-B for instance I think that is only ever rated for 60 C and hence it tops out at 55 amps (which is 50 amps for all practical purposes).

In my case, I ran the entire run in EMT (solid metal conduit) back to my breaker over a ten foot run. I then installed a 75 degree C rated 60 amp breaker.

https://www.cerrowire.com/ampacity-charts

trdrum | 07. Oktober 2019

So I'm a new S60 (2014) owner that is about to take delivery and has an electrician installing a 60 Amp circuit, which allows me to charge at 48A safely. My understanding is that the UMC limit is 32 amps with the NEMA 14-50 plug.

Let's say that I WANT to charge at 48 amps - what are my options? I'm thinking I could purchase a non-Tesla charging unit that is adjustable (such as ChargePoint) and use the proper plug adapter, but would I be wasting my time because my older Model S not charge any faster than 40 amps? Or am I reading this all wrong?

Sorry to be daft, but I'm still learning and this is a good bit of information to parse.

trdrum | 07. Oktober 2019

Sorry to post my question here - just realized this is MX thread!!!

Hugh-SG | 07. Oktober 2019

No worries. May I suggest you scroll up to a post by "dortor" in 2017.

That person provided an excellent explanation that I think will answer your question.

... and congrats on acquiring your Tesla. I got mine Used as well and it has been voyage of discovery and wonder for the past 6 months.

Kindest regards,
Hugh-SG

Vawlkus | 07. Oktober 2019

Since it’s here, I’ll answer anyway. Your car will top out at 48a for charging (unless you’ve got dual chargers - doubtful).
The HPWC is your only Tesla option, but other chargers can handle that load as well. Only drawback will be that any other charger will not be able to lock to your car, and you’ll have to use an adapter (likely the J1772). If you’re parking indoors, it won’t be an issue, but parking outside means any mischief marker can unplug your car.

Vawlkus | 07. Oktober 2019

Since it’s here, I’ll answer anyway. Your car will top out at 48a for charging (unless you’ve got dual chargers - doubtful).
The HPWC is your only Tesla option, but other chargers can handle that load as well. Only drawback will be that any other charger will not be able to lock to your car, and you’ll have to use an adapter (likely the J1772). If you’re parking indoors, it won’t be an issue, but parking outside means any mischief marker can unplug your car.

Passion2Fly | 07. Oktober 2019

Gen1 portable chargers can handle up to 40A. You might want to get one of those on eBay...