S100D won't charge faster than 48A

S100D won't charge faster than 48A

I have a mid-December 2018 S100D.
I have 100A service to a home charger that works fine on the originally-installed Tesla Home Charger on a 60A breaker.
It charges at 48A.
I recently upgraded the 60A breaker to an 80A breaker (and moved the Charger setting from "9" to "D" - per the manual).
I was expecting that my S100D would then allow me to increase the charge rate (from the S100D control panel in the car) from 48A to 72A.

But, the S100D shows no ability to increase past 48A?

How do I get that up to 72A?

-Pat Quinn
Portland, OR USA

p.c.mcavoy | 24 giugno 2019

Have you confirmed that your onboard charger is actually capable of 72 amps? Tesla has changed around a couple times whether 72 amp onboard charger is included.

If you do have 72 amp charger, then you may need to set the amps up on your charging screen when you’re plugged in at home. If that’s just the case, you would see it show 48/72 amps on the charging screen when actually charging. If it shows 48/48 amps, then this suggest you actually only have the 48 amp on-board charger.

quinn47 | 24 giugno 2019

@p.c.mcavoy -- I think the install details were all done correctly. I did not realize that a car that can accept a "Supercharge" might be otherwise limited to 48A. But, that is exactly how it is behaving. Any idea how to find out the rating of my on-board charger? Thank you.

p.c.mcavoy | 24 giugno 2019

One method would be to check your purchase documents and see what it might show in the specs.

The other is plug it in at home, start charging, then look at what it shows in the car on the charging screen. You should see the amps listed as either 48/48 or 48/72. The first number is the amps your charging at. The second is the max allowed.

If it shows 48/72, then you need to just up the amps on the screen in the car.

If it shows 48/48, then something it telling the car that 48 is all that’s available, either by the HPWC or the charger inside the car or the car only has a 48 amp charger. Given you’re confident the HPWC is set to 80 amps (your D setting comment), then this would tell me you only have a 48 amp on-board charger..

Bighorn | 24 giugno 2019

Cars are variably able to accept 40/48/72/80 Amps depending on vintage and installed equipment. Google might help narrow down your vehicle’s configuration.

murphyS90D | 24 giugno 2019

You can't charge at 72 amps on an 80 amp breaker 64 amps is the maximum.
To charge at 72 amps you need a 90 amp breaker. 80% of 90 = 72.
Hopefully that 100 amp circuit was run with #3 or #2 copper wire.

Dramsey | 24 giugno 2019

Your car is limited to 48 amps, as I understand it. Original Teslas, prior to HW2, could charge at up to 80 amps on a home charger, although you had to specify "dual chargers" as an option when you configured the car. My 2013 Model S could charge at 80 amps.

Subsequent models like my current 2016 Model S were limited to 72 amps. As far as I know, Tesla never explained why they did this.

Current cars are limited to 48 amps. Again, Tesla has not explained why they reduced the maximum charge rate.

Keep in mind that charging with DC at a Supercharger and charging with AC at home are two entirely different things.

whodat | 24 giugno 2019

Hi Pat,
You may need a dual charger. If you don't have a dual charger, you may have to buy the dual charger and then you may need to setup a service appointment for Tesla to install the 2nd charger. The dual charger option enables double the charging current. For my 2016 model S 90D, I can charge at 80A with the dual charger. With the single charger I was limited to 40A. Hope this helps.

Bighorn | 24 giugno 2019

Dual chargers are not a thing anymore.

EVRider | 25 giugno 2019

Tesla discontinued the high amperage (72 amp) charger just after I ordered my S100D at the beginning of November. My S100D (delivered mid-December) still has it, but any cars ordered later would not. The order invoice will list the high amperage charger if you have it. | 25 giugno 2019

Since Tesla likely has data on AC charging usage, they likely found so few used more than 48 amps, that it was a waste to offer 80/72 amps. Not saying it isn't useful to some, but when a hardware related feature gets into the 1% usage category (a guess on my part), it's not worth the production and inventory complications. True of most companies although there are exceptions,. A few car companies like Porsche, specialize in hundreds of outrageously expensive options that can be custom ordered. Perhaps that's why in a few short years, Tesla now outsells Porsche. I do like having more options than less, but you don't always get everything you want - and the price is often far lower with bundled/standard features that everyone gets.

mizunosan | 25 giugno 2019

Yes... your car just missed the cutoff it appears for the 72 amp on board charger. My 2018 Model S100 was delivered in September and I can charge at 72 amps at home. It really helps with the added speed compared to my wife's Model 3. I drive quite a bit and getting that extra boost when I stop by at home before heading out again is fantastic.

Dramsey | 25 giugno 2019


"Since Tesla likely has data on AC charging usage, they likely found so few used more than 48 amps."

Possibly, but it does follow Tesla's years-long pattern of reducing the number of options available. Now you have, for a new Model S, these equipment choices:

* Standard / long range / performance
* Paint color
* Interior color (scheme)
* Wheels

...and that's it (autopilot/FSD is a software upgrade).

In some cases, formerly optional items like the premium interior, air suspension, high end audio, and HEPA filtration have been made standard.

In other cases, options like roof type, interior trim choices (remember when you could choose among 4 different types of wood trim as well as piano black and carbon fiber?), and high amperage chargers have simply been eliminated.

In the first case, making formerly optional items standard is obviously to improve the average profit per car. This substantially raised the base price. For example, the base price of my late 2016 Model S was $66,000...and the base price of a Model S today is $75,000. Granted this gets you a much nicer car and the new cost is less than the old car with the same options added.

In the second case, they're trying to simplify production. Making three standard interiors is a lot simpler than the dozens of possible variations previously available.

It seems to have worked. I configured a new Model S Long Range and the configurator says it would be available within two weeks; I waited months for my two previous cars. Also, at $94,000, it's significantly cheaper than my current car, which stickered at $115,700...and it's a better car to boot.

That said, I still miss the degree of personalization we used to have. And while normally charge at 50 amps, the ability to go to 72 amps comes in REALLY HANDY every month or so.

bp | 26 giugno 2019

Our 2012 S P85 had the dual chargers with an HPWC on a 100A circuit, able to charge at 80A. And, we only needed to charge at the full 80A a few times when getting ready to leave for a road trip in the evening - and once the supercharger network was available, we never needed to charge at 80A.

We didn't purchase the 72A option for our 2017 S 100D (though it appears we have a 72A onboard charger that is software limited to 48A). After 30K miles, 48A charger has been enough to handle our charging needs at home and on trips.

Our 2018 X 100D has a 72A charger. It's connected to an HPWC on a 60A circuit, able to charge at 48A - and that has also been enough to handle our home charging needs.

Tesla likely has data on vehicle charging patterns, including what charging rate was used, how long the vehicle charged, and how long it was parked afterward connected to the charger (indicating whether faster charging was actually needed).

It's highly likely most owners either have 48A (or less) charging at home or based on their charging history didn't actually need charging faster than 48A.

While we could pay to upgrade our S 100D from 48A to 72A, we probably wouldn't need the faster charging, certainly not enough to justify spending $1900 to remove the software limit on the charger...

eazy70d | 26 giugno 2019

It does not matter what circuit you install at home. You will max @ 34miles per hr which will prob cap at 48 watts even if you have a 100amp breaker. you can only see the higher amp charging at the stations.

check here - | 26 giugno 2019

@eazy70d - 48 Watts would be really slow! Sure you meant 48 amps. 240v x 48 amps = 11.5 kW.

inconel | 26 giugno 2019

Given that we use around 300W/mile, at 48W we will get 1 mile added every 6 hours, 4 miles per day, 2 months for 240 miles.

mvotb | 26 giugno 2019

Like Murphy said, I hope you understand that you can't just change breakers, unless you have the proper wire size for the higher amp breaker.

eazy70d | 27 giugno 2019

@teslatap, mybad you're right! I meant 48 amps and 11.5kW. You can see the chart in my link. the home system will plateau at 34 miles/hr so it doesn't matter what size breaker you use. Because of that, i just went with 60amp breaker. Free super charging for me anyway. I just have the wall charging incase I need it or go out of town.

circuit breaker (amps) 60 max output (amps) 48 power 11.5 kW max miles - 34

scott | 27 giugno 2019

The home system doesn’t max at 34 mi/hr. If you have the 72A duel chargers installed and a 90A+ feed you can get at least 52 mi/hr.

p.c.mcavoy | 28 giugno 2019

@scott - Newer vehicles no longer come with nor appear to have the option for 72A on-board charger. That's the situation of the OP and context of this thread where home charging is limited to 48A even with HPWC installed properly on a higher amperage circuit.

batemanrandall | 19 ottobre 2019

Have a 2016 Model X @ 72A charging. Was going to get a 2019 Model S, but 48A limit won't work for us due to trips to rural areas (where we have 72A chargers installed) and travel between them. Is there a way to replace a 48A charging unit with a 72A (or higher) unit aftermarket? Our dealership stated 72A is no longer an option due to majority not needing this. I'm not fond of the one size fits all approach...

tes-s | 19 ottobre 2019

I asked also, and was told they would not put in a 72a charger.

My MS has 80amp charging - if you buy a new one with 48amp I'll trade you. I'll even throw in a new signature wall connector.

Anthony J. Parisio | 20 ottobre 2019

Why won’t it work for you? Do you really need the speed. You do realize that you can have a higher voltage going into a lower voltage charger. It won’t take more than it needs. It will not hurt the car. You really don’t have to change anything about your charging setup. The only differences it will take longer to charge. If you’re OK with that go ahead and get a new car.

murphyS90D | 20 ottobre 2019

My car has 80 amp charging. I usually charge at 50 amps because any higher than that causes the voltage to drop below 240 volts even though I installed #2 copper wire. Unfortunately it's 75 feet long.

tes-s | 20 ottobre 2019

What is the voltage at your panel when you are charging at 80amps? It may not be the run from the panel to the wall connector where the voltage drop occurs.

murphyS90D | 21 ottobre 2019

From the panel to the outside disconnect and meter box is a huge service entrance cable that it took two strong guys to install. I don't know what size it is but assume it is correct for 200 amp service. The inspector commented that it had the required 4 wires since the neutral ground tie is in the main disconnect box. The voltage is supported by a 10 kW PV solar array on the roof that is also connected to the main disconnect. I haven't measured the voltage at the panel when under the 80 amp load. I'll put that on the to-do list.

tes-s | 21 ottobre 2019

75ft #2 copper should only see 1% voltage drop at 80amps. If you see more than 2 or 3%, there could be something else wrong.

Anthony J. Parisio | 21 ottobre 2019

Remember if you want to charge at 80 Amps you must have at least 100 amp breaker and 100 amp wire to the wall unit. Also the unit must be set for 100 A. The car is smart enough to always be 20% less then whatever it is given.

murphyS90D | 21 ottobre 2019

#2 copper is more than adequate for 100 amps.

murphyS90D | 23 ottobre 2019

That was an interesting measurement. The drop from the panel in the basement to the sub-panel in the garage with 80 amps flowing is 2 volts.

As measured by the car the voltage during ramp up is:

245 volts at 0 amps.
238 volts at 40 amps.
232 volts at 80 amps.

The majority of the drop is in the feeder cable from the pole across the street to the service disconnect on the side of the house. The transformer for the block is on that pole.

That is within + or - 5% of 240 volts so it's probably within spec for a power company feeder.

starojam | 23 ottobre 2019

Tesla went from single/dual 40 amp modules- max of 80 amp to double/triple 24 amp modules in vehicles or 48/72. Tesla prefers to not upgrade or change vehicle charging configs after vehicles are out from factory. However if you get to a service manger and talk to them there are sometimes options to get an additional module installed. This is all done within the vehicle. Once the vehicle is capable of 80 or 72 amp you then need to have a HPWC or J1772 unit that is able to charge at either 80 amp (tesla) or 75 amp juicebox. The modules for an S are usually under the back seats.As for circuit breakers or electrical in US it is 80% of what is listed is max load. so a 100 amp breaker will carry a 80 amp load. This is to protect the wire used. The wire used depends on load and length.

Best of luck on trying to get an upgrade as it takes patients and navigating Tesla's ever changing internal policies.

KSS | 2 novembre 2019

SC can still add the charging module. It is off the vehicle config options while ordering. It used to be an option, then they made standard for all 100d, and then took it off not even left on the config option. But if you want you can still get it.

AERODYNE | 2 novembre 2019

I keep my Gen 1 mobile connector in the car, it has 3 years left on warranty. Bought a Gen 2 connector and hard mounted to garage wall. I charge at 27A which is 20+ miles per hour, plenty for me. The Gen 2 has already thrown errors and only has a 1 year warranty. It gets warm at RT and 10% like ess than max rated ps, never see less than 235v at the car.

I think 200 miles of added range per day would be plenty for most folks.

tes-s | 2 novembre 2019

@murphyS90D - that is what I suspected when I suggested taking those measurements. 2V drop is what would be expected from the panel to subpanel with #2 copper.

My guess is the drop is not your feed, but the transformer itself. Too many houses on the one transformer - pole transfomer probably 25kVA? At 80A you are pulling a good chunk of the rated capacity, though I understand power companies often load them higher.

Wouldn't hurt to notify the power company - even if within spec, they may take some of their own measurements and perhaps decide to install another transformer.

As the OP noted, Tesla no longer sells cars that can take 80amp (20kW) charging. But there will be more and more homes with two EVs, so 20kW charging loads will still be out there.

Tesla-David | 3 novembre 2019

I have 100 A breaker and 1st generation HPWC (2013) and added second onboard charger ($2k) to our 2015 MS85D in 2015, to enable charging at 80A in our garage. Too bad that adding second onboard charger is no longer an option, as it is nice to have that ability, when you need a quick charge. However, we rarely charge at that rate now after adding two Powerwall PW2's to our 13.2 kWh solar PV system last year. We have to limit our charging of MS and M3 to under 30A to stay within the parameters of PW2's so that we do not trigger grid draws unnecessarily. It is still nice to have that capability using destination HPWC's on trips where available.