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Installing the Tesla Wall Connector - Output Current?

Installing the Tesla Wall Connector - Output Current?

In the installation manual for the wall connector there is a rotary switch that sets the maximum current that the wall connector is allowed to draw (based on your wire gauge used and circuit breaker size). If I go for max, using a 100A breaker and appropriate wire gauge, I can set it for 80A. Does this mean that the Model 3 will actually charge at an 80A rate? I think I read somewhere that a wall charger is limited to 32A with a Model 3. And if that's the case, why do I have an option to go as high as 80A? Does that only apply to a model X or S?

wingsy | May 18, 2019

I may or may not have answered my own question. According to this chart, 48A is all I can get from the wall connector for a Model 3. I have a Model3+, so I hope I can get 48A out of this thing.

https://www.tesla.com/support/home-charging-installation/wall-connector

roger.klurfeld | May 18, 2019

The charger is actually in the vehicle. The maximum charge rate using a wall connector is 48 amps, provided the wall charger is hard wired. If it is the plug-in variety, the maximum charge rate is 40 amps. If you use the mobile connector, version 2, the maximum charge rate is 32 amps.

kevin_rf | May 18, 2019

If you have a long range (310 miles, LR , LR AWD, Performance) the model 3 can charge at rates up to 48a. If you have one of the shorter range vehicles, SR, SR+, or MR you are limited to 32a.

That said, if you plan in the future going with a second Tesla (spouse, kids driving), you can daisy chain up to four wall connector off the same breaker. So a 50a or 60a breaker would make sense. Larger breakers require larger wires driving up cost.

Either way, enjoy!

EVRider | May 18, 2019

Model S and X with the high amperage charger (no longer available) can charge at 72A. Older Model S’s with the dual charger can charge at 80A. That’s why the wall connector supports 80A charging.

Linebet | May 18, 2019

@kevin_rf, I have a Model 3 LR, and it only charges at 32A. I plug into a 14-50 outlet.

kevin_rf | May 18, 2019

Linebet, 32a is the limit of the mobile charging cable, not the LR. The LR limit is 48a. The OP is looking at a wall connector which when setup with the correct wiring and breaker can charge at the limit of the car. 48a for LR, 32a for the rest.

Linebet | May 18, 2019

Thanks.

Tronguy | May 18, 2019

Just so we're clear on this: The charger in the car won't draw more than the maximum of (a) the amount the charger can handle or (b) the amount that the electronics on the other end of the cable plugged into the Tesla says it can handle. Finally, if the electronics on the other end of the cable Sees Something Odd (unbalanced 240 AC, 120 VAC with a sudden drop in voltage as the current goes up (signs of a small-wire extension cord) or something like that, the current draw will be dropped. That last is called a "Safety feature that is nice, but one shouldn't depend upon it if one is thinking life and limb".
So, this approach has its advantages. Suppose one puts in the wires and breakerage to handle a full-bore Model S, which can do 80A steady state and requires a 100A breaker. A Model 3 LR plugged into that isn't going to draw more than 48A because of the limit in its internal charger; the right kind of Model S will draw 80A; and a Model 3 SR will draw its max, 32A I think.
On the other hand, the bigger gauge wire costs more; there can be issues with how big a breaker one can put into a given amperage service; and so on. So, suppose one has a 100A breaker box, the electrician says it's ok for a 40A breaker, but no more; so one sets the switches for 32A max, and that's the max _any_ car is going to do plugged in there.
It's just possible to get into trouble with this scheme. Suppose that one puts in wire that's only good for 20A, sets the switches for 32A, the car tries (and maybe!) succeeds at 32A, then we all have fun watching the house burn down. So, don't do that :).

wingsy | May 18, 2019

If the charger inside my M3+ can only charge at a max current of 32A, then how is it that a SuperCharger can charge it at a bazillion amps?

I want to be able to see my neighbor's house lights dim when I plug in my M3.

RichardKJ | May 18, 2019

The Supercharger bypasses the charger in the car and feeds DC directly to the battery (tempered by some electronics). In fact a Supercharger is basically a stack of the in-car charger modules.

kevin_rf | May 18, 2019

In a nutshell, when you charge at 120v/240v the 32a/48a supplies in the car convert the input ac to 350-400v DC at 16-24ish amps.

The super charger is already at 350-400v DC so it bypasses the chargers and directly chargers the batteries. Either my brain is fried, or a 250kw DC charger is delivering 400v DC at 625a!!! That's meth scary.

wingsy | May 27, 2019

Confirmed. Wall connector max current set to 48A, M3+ charges at 32A.

Tesla2018 | May 27, 2019

If you have a model S with 80 Amp charging capacity, how many miles per hour of range do you get while charging as compared to a regular model without the dual chargers? At a supercharger it wouldnt make a difference. Since supercharging is free for life for most of the earlier cars, why did people spend thousands more for the dual charger if it only speeds up at home charging?

EVRider | May 27, 2019

@Tesla2018: The high amperage charger in my 2018 Model S charges at 72A and gives me about 52-53 miles of range per hour. Unlike the old dual chargers, the high amperage charger became standard equipment on the 100D so I didn’t pay extra for it (and wouldn’t have). Tesla discontinued the high amperage charger shortly after I ordered my car.

tedmbrady | May 27, 2019

I have a Model 3 long range AWD. I have the wall charger with 6 gauge wire, 60A breaker and set to "9" which is 60amp, max 48A output. So my car will get 48A if I need it to. But then I also dial it down in the car (or phone) cuz I do not need that kind of demand on a daily basis. I usually have it set to 36A.

ADinM3 | May 27, 2019

@tedmbrady, just curious what made you dial back the amperage and in particular pick 36A? Was it trying to be easier on battery, concern over wires heating, something else, etc? Just curious as most usually max things out.

If your 6awg wiring is not individual wires pulled through conduit (i.e. THHN, not 3 or 4 NM-B wire), then you made a good choice as 6 gauge NM-B is technically not enough to pull 48A continuous load.

tedmbrady | May 28, 2019

ADinM3, I have the correct wiring, I just don't need the speed at which 48A charges (although occasionally it is nice to have) vs the load on my service. 48A is not a small load, and when also running the dryer, rest of the home, etc I just don't see the need. That's all.

tkarma97 | December 8, 2019

I’m installing a twc to a 60 amp breaker with 6 gauge wiring. SR+ limits charging to 32amp. Should I set the wall connector dial to max 48amp or dial it down 40 or 32 amp? Is there any benefit with lowering the setting below max 48 since the car internal charger will limit to 32 amp max regardless?

jmccpa | December 8, 2019

My garage Tesla Wall Charger was installed with a 100 amp breaker and charges my LR-RWD at 48 amps with no issues.

Lonestar10_1999 | December 8, 2019

@tkarma97 - not all 6 guage wire is compatible with a 60A breaker. I am using 6 guage Romex with a 50A breaker. Check with a qualified electrician to ensure you are code compliant.

https://www.cerrowire.com/products/resources/tables-calculators/ampacity...

mrburke | December 8, 2019

@tkarma97 - Set your TWC to 60amps. It won't hurt.
Who knows, a future update may increase the charging current of your SR+

mrburke | December 8, 2019

Sorry - I should have said "Set your TWC to 48amps" 60amps x 80%

tkarma97 | December 8, 2019

Thanks @ mrburke. I will ask the certified electrician to set at 48 amps.

Tronguy | December 8, 2019

@tkarma97: Let's get this straight. Let's say you have a 60A breaker in the breaker box. Code says max continuous load on a 60A breaker/60A wire/60A socket is 80% of that 60A, which is 48A
The "socket" in your case is the TWC,
I got the manual in front of me (handy, those web searches). With a 60A breaker and 60A wire, the TWC should be set to position "9", 48A output.
This sort of makes everything match up. And if somebody comes over with a LR or better, they get the full 45 mph charge rate :).
Aaannd.. Just to clear up a bit of misinformation in this thread.
The power company charges you on _energy_, not power. 1000 watts for 1 second is the same amount of energy as 100 watts for 10 seconds, or 10 watts for 100 seconds. (This is why the charges on your electric bill are in cents per kW-hr.. note the units of power x time).
So.. If you're charging to, say, 80%, the amount of energy stored in the battery is the same, and the cost of that stored energy is the same, whether you're charging at 24A or 32A.
Now, there is a _slight_ increase in power consumption with I*I*R losses, maybe 10-20 W or so (it's what makes the cable warm); but, on the other hand, AC-DC inverters often have a "sweet spot" where their efficiencies max out. So, frankly.. just leave it at 32A.

tkarma97 | December 8, 2019

@Tronguy, are you saying set to 80% of max load at 48 amps or lower to 32 amps.

Magic 8 Ball | December 8, 2019

I rarely disagree with Tronguy but I see no reason to throttle current at the HPWC, current can be throttled in the car. If you have a friend with a LR or you get a LR in the future you will be ready.

Tronguy | December 8, 2019

@tkarma97: the manual is at
https://www.tesla.com/support/installation-manuals-wall-connector, click on the link for North America installation manual.
Look at pp. 22 of the pdf, there's a table. If you've got a 60A breaker, you set the switch to number "9", which is max output current of 48A, which is, by electrical code, the maximum steady current a 60A breaker/wire gauge for 60A should handle.
Note that the breaker and the wire gauge _must_ be matched to pass code.
If you use a wire gauge good for only, say, 50A, then you must use a 50A breaker and set the TWC to position 8, which will give you the safe max current of 80% of 50A, 40A.
That clear?

tkarma97 | December 8, 2019

Yes, that makes sense now.

Tronguy | December 8, 2019

@M8B: Absolutely correct. If he has 60A wire and a 60A breaker, set the switches to position 9 (what the manual says to use with 60A breaker), which'll max current the whole business at 48A.
I think we're in violent agreement, as my son would say :).

andy.connor.e | December 8, 2019

Some would call it frog insurance.

Magic 8 Ball | December 8, 2019

Violent agreement, roger that.

Lol

Tronguy | December 8, 2019

@andy.conner.e: That's the "pot getting warmer until the frog gets boiled" bit.
Thing is, I figure the electrical code works on several levels.
First off: I've professionally sized fuses for circuit boards I've designed.Slow-blow, fast-blow, etc. We who design circuit boards don't believe in arcs and sparks Star Trek style: We'd like our failing circuit boards to make a faint "pfft" and just stop working.
In any case, say one has a 5A load.One doesn't use a 5A fuse. A 5A fuse is 5A+-5 or 10%; so, at 5A steady state, that fuse might blow, or not blow. Further, there's always turn-on surge currents. Sometimes they're big, sometimes they're small, and some fancy I*I*t math kicks in to size the fuse (and whether it's fast or slow blow).
While I'm definitely not an electrician, I can read manuals and get the idea pretty quickly. Further.. Say one has a NEMA14-30. _Somebody_ did a study: contact wear, screw tightness, corrosion, current, what metals, plastic aging, plating metals, how many plug ins/plug outs, and so on.
And this ends up in the National Electric Code: This socket/plug combination, installed to code, with the right gauge wire and the right size circuit breaker, Will Not Catch A House On Fire.
So, they put in all sorts of safety margins. And it's so well engineered that people can push the boundaries.. and get away with it. And they announce to the world, "I got away with it! You can, too!"
Dangerous as heck, that line of thinking. Yep, a 100 houses may not actually burn down.. But that won't be much consolation to the people in the 101st. And this is why Building Permits are a Good Idea - because not only are there tyros out there screwing up, big time, there's the occasional electrician who buggers it up. And paying for another set of eyes to make Sure It Was Done Right is a good idea.
Down off my soap box..

keith | December 8, 2019

I'm surprised that so far nobody has mentioned that the Wall Connector can handle one, two or three phase supply. The WC that came with my M3 is limited to 32A, but the installation manual point out that at 230V 3-phase the unit is rated at 22kW. Single phase, it charges at up to about 7kW. In my country most homes have a single phase supply, but with the popularity of induction cooking (and air-con etc) multi-phase installations are becoming more common.

kevin_rf | December 9, 2019

Keith, I'm pretty sure you need the European Tesla plug to support 3 phases. The US plug with two pins cannot/does not support the third phase.

I do find it interesting you can charge at 22kw... Would be nice ;-)

DirkFirkin | December 9, 2019

European Wall Connector on 3 phase 16 amp 230 volts here.

This give a consistent maximum AC charge of 11KWh....

andy.connor.e | December 9, 2019

@Tronguy

I design electrical systems for commercial data centers, so i've got a pretty good understanding of high power applications. Knowing the electrical code for me is part of my job.