New Model X charging limit to 32A

[MorrisonHiker]

Personally, I see the corded HPWC as a bit of a waste, unless you already have the NEMA 14-50 installed. Then it's essentially just a nicer looking, more permanently attached gen 1 UMC. If you need to involve an electrician, then just hard wiring it at 60A is the better path.

The HWPC's best benefit is when you have more than one Tesla. We have 4 Teslas currently and at any given time, we have 3 of them plugged in. The HPWCs allow us to have one main breaker which is load balanced/shared between 3 wall connectors (up to 4 are supported) and it automatically splits the load between cars that are actively charging. We currently only have 64 amps (on an 80 amp breaker) split between the 3 HPWCs. That allows one car to charge at 48 amps, 2 cars to charge at 32 amps each or 3 cars to charge at 21 amps each. We have the wiring to up it to 80 amps (on a 100 amp breaker) which would allow us to have 1 car at 48 amps, 2 cars at 40 amps each or 3 cars at 26 amps each but were told we need a firmware update on our Powerwalls before we can bump things up. If our cars had more than a 48 amp chargers, then we'd be able to charge an individual car at 64 to 72 amps.

Of course we don't usually schedule all cars to charge at the same time...but if they need to, we don't have to consider the load since the HPWCs handle it automatically. Previously, we had 2 14-50 outlets and were able to have two cars plugged in at once but we didn't have the ability to have 3 cars charging at 240 volts simultaneously.

 

[jboy210]

The HWPC's best benefit is when you have more than one Tesla.

I like just knowing the Mobile charger is always in the frunk and not connected at home. A few times I have decided I need to take a trip to No Supercharger country like the remote mountains.

 

[Krazaak]

The HWPC's best benefit is when you have more than one car. We have 4 Teslas currently and at any given time, we have 3 of them plugged in. The HPWC allow us to have one main breaker which is load balanced/shared between 3 wall connectors (up to 4 are supported) and it automatically splits the load between cars that are actively charging. We currently only have 64 amps split between the 3 HPWCs. That allows one car to charge at 48 amps, 2 cars to charge at 32 amps each or 3 cars to charge at 21 amps each. We have the wiring to up it to 80 amps which would allow us to have 1 car at 48 amps, 2 cars at 36 amps each or 3 cars at 24 amps each but were told we need a firmware update on our Powerwalls before we can bump things up.

Of course we don't schedule all cars to charge at the same time...but if they need to, we don't have to consider the load since the HPWCs handle it automatically. Previously, we had 2 14-50 outlets and were able to have two cars plugged in at once but we didn't have the ability to have 3 cars charging at 240 volts simultaneously.

I agree, I was referring to using the corded HPWC plugged into a NEMA 14-50. Curious on your setup, because I may add a 2nd HPWC if I ever get my referral reward delivered. My understanding was that any HPWC plugged into a vehicle reserved 8A. Is that why you have a 64A breaker, so you can get a full 48A charge on 1 vehicle while the other 2 are plugged in and not charging? I assume if that's the case then you would only get 28A on 2 vehicles charging simultaneously with the 3rd plugged in.

Mainly, I'm wondering if I'm going to need to upgrade the 60A breaker when I add the 2nd HPWC.

 

[MorrisonHiker]

I agree, I was referring to using the corded HPWC plugged into a NEMA 14-50. Curious on your setup, because I may add a 2nd HPWC if I ever get my referral reward delivered. My understanding was that any HPWC plugged into a vehicle reserved 8A. Is that why you have a 64A breaker, so you can get a full 48A charge on 1 vehicle while the other 2 are plugged in and not charging? I assume if that's the case then you would only get 28A on 2 vehicles charging simultaneously with the 3rd plugged in.

Mainly, I'm wondering if I'm going to need to upgrade the 60A breaker when I add the 2nd HPWC.

I don't know about an 8 amp reservation for each WC. Do you know where you saw that? We just asked for the highest possible when we had things installed and at the time, they said our Powerwalls could only support up to 64 amps so that's what we got. We get the full 64 amps as I mentioned earlier. If only two cars are charging and the third is plugged in, they each get 32 amps, so no 8 amp reservation.

I assume you could still use a 60 amp breaker to provide 48 amps to one car, 24 amps each to 2 cars or 16 amps each to 3 cars.

 

[Krazaak]

I don't know about an 8 amp reservation for each WC. Do you know where you saw that? We just asked for the highest possible when we had things installed and at the time, they said our Powerwalls could only support up to 64 amps so that's what we got. We get the full 64 amps as I mentioned earlier. If only two cars are charging and the third is plugged in, they each get 32 amps, so no 8 amp reservation.

I assume you could still use a 60 amp breaker to provide 48 amps to one car, 24 amps each to 2 cars or 16 amps each to 3 cars.

It was another thread on this board, but I can't find a link to it. The claim was that a car plugged in and not charging always had 8A available to it. If you're getting 32A on two cars while the 3rd is plugged in, then that's obviously not the case.

 

[ajdelange]

Is that a state/local thing?

Darned if I know. I was summarizing what others had posted here.

 

[Fiver]

It was another thread on this board, but I can't find a link to it. The claim was that a car plugged in and not charging always had 8A available to it. If you're getting 32A on two cars while the 3rd is plugged in, then that's obviously not the case.

As someone who has installed and extensively used a 100amp line shared between 3 HPWC I can give you a little color on this.

The HPWC is dynamic, but it's SLOW to be dynamic. If three cars are plugged in, and one tops off and stops charging but remains plugged in, the other 2 don't just instantly jump up to use the freed up additional power (If they can even take it). It can take upwards of 10 minutes for the loads to slowly shift to the other two cars that are still charging. Some people confuse this as being a phantom load on plugged in cars that aren't charging, but if they just waited longer, they would see it will eventually even out. I do in general usually notice a 1-4amp load on cars plugged in but not charging, but it varies usually towards the low end of that.
The flip side of this is if a new car plugs in, the load quickly drops to a fair split between the charging cars or if a car unplugs, then the load also quickly is re-assigned to the remaining cars.
Also secondly stuff in the car (someone running the HVAC system after being topped off) might draw power even though the car isn't technically "charging" it's just keeping the battery at the proper SoC. Just running the heat on a cold morning can pull 6-8kW from a HPWC just to maintain a battery SoC when already at 90%. This can effect the other chargers.

 

[gnuarm]

Is that a state/local thing? I had a lot of wiring done for the Model X. We installed a signature HPWC, but wanted the option to remove it and use the same wiring for a NEMA 14-50 outlet if we got a different brand EV in the future. So they redid the breakers to be 50 Amps instead of the 40s that were already there. When I asked my electrician about that he said he could not legally connect a NEMA 14-50 outlet to a 40 Amp breaker. It had to be 240v at 50 Amps.

FWIW, we are in California in the SF Bay Area. (13 miles from Tesla )

I have read that the NEC says you can use a 40 amp circuit on the 14-50 outlet if that is what your load should be wired to. Seems there are 40 amp appliances, but no 40 amp connectors, so they use the 50 amp connector.

However, while the NEC is national, it has no authority to set standards anywhere. It is up to the states to adopt or not adopt the NEC requirements. So ask another electrician in your state.

There is some real irony that your electrical won't install the outlet on a 40 amp circuit and Tesla has decided they have to assume this outlet is on a 40 amp circuit and so only let the car draw 32 amps.

Tell your electrician you need a 40 amp circuit and ask what outlet he recommends? Does he recommend you use a 50 amp circuit with a 40 amp device?

 

[doghousePVD]

In the US, a NEMA 14-50 has to be installed on a 50 amp breaker. Code requires that continuous loads for over 3 hours must be derated to 80%, so the max allowed is 40 amps. Canada made an exception for electric stoves, so NEMA 14-50 are often installed on 40 A circuits. That's why early chargers used 40 A, which to comply with the Canadian code, were downrated to 32 A.

If one is using a wall charge, one can adjust the power to what you want. In my case, I have only an 80 A circuit feeding it, so code maximum is 64 A, which I set in the car. Occasionally, if I am in a rush, I will run at 72 A, but for less than 3 hours. If the charger could charge at 80 A, there is no danger in running it at 80 A for less than three hours.

There are a lot of stupid comments on the Internet about plugging lower amperage devices into high amperage outlets is "bad". Circuit breakers are to protect the house wiring, so it does not catch on fire; breakers are not to protect the device. Of course you can plug in a low powered device. How do you think you plug a night light into a regular 15 A outlet.

Anyone see the new Tesla wall charger that is only 40 A? https://www.engadget.com/2019/01/16/tesla/-ev-charger-nema-plug/ [The original wall chargers is/was 72 A]. How does this work (marketing-wise, not technically) with the new (crippled) 32 A on board chargers? (I wish the onboard could charge faster than my present 72 A)

 

[tga]

In the US, a NEMA 14-50 has to be installed on a 50 amp breaker. Code requires that continuous loads for over 3 hours must be derated to 80%, so the max allowed is 40 amps. Canada made an exception for electric stoves, so NEMA 14-50 are often installed on 40 A circuits. That's why early chargers used 40 A, which to comply with the Canadian code, were downrated to 32 A.

It's within code in the US to install a 14-50 on a 40A breaker, provided the nameplate rating of the appliance being plugged in is 40A or less. But, IMHO, it's a cheap and hacky way to save a few bucks on wire (8ga vs 6ga).

If one is using a wall charge, one can adjust the power to what you want. In my case, I have only an 80 A circuit feeding it, so code maximum is 64 A, which I set in the car. Occasionally, if I am in a rush, I will run at 72 A, but for less than 3 hours. If the charger could charge at 80 A, there is no danger in running it at 80 A for less than three hours.

Maybe I'm being somewhat pedantic, but NEC 625.14 clearly states EV charging is always classified as a continuous load, without the 3 hour qualification, so technically, that's a code violation:

625.14 Rating. Electric vehicle supply equipment shall have sufficient rating to supply the load served. For the purposes of this article, electric vehicle charging loads shall be considered to be continuous loads.

Anyone see the new Tesla wall charger that is only 40 A? https://www.engadget.com/2019/01/16/tesla/-ev-charger-nema-plug/ [The original wall chargers is/was 72 A]. How does this work (marketing-wise, not technically) with the new (crippled) 32 A on board chargers? (I wish the onboard could charge faster than my present 72 A)

It says in the description: "Provides 40 amps (9.6kW) of power for all Model S, Model X and Model 3 Long Range vehicles. Model 3 Mid Range and Standard Range vehicles will charge at 32 amps when using the 14-50 Wall Connector. "

 

[ajdelange]

The charger tells the OBC how much power it can have

Regular wall charger: Available power set by rotary switch in unit: 72A max
Charger that comes with car with 14-50P adapter: 32 A
Corded charger (14-50P): 32 A (?)
This new charger: 40A

Your car determines how much power to draw up to the limitation of what it has been told is available and the capabilities of its OBC.

After reading about this new charger I am having to deal with a sore arm from patting myself on the back for having the foresight to install a couple of 14-50R circuits in my summer place. Better yet if I toss it in the frunk with other charging stuff I might be able to convince customs that it stays with the car.

 

[Rocky_H]

(1)Regular wall charger: Available power set by rotary switch in unit: 72A max
(2)Charger that comes with car with 14-50P adapter: 32 A
(3)Corded charger (14-50P): 32 A (?)
(4)This new charger: 40A

Corrections:
(1) Can do 80A maximum, which can be used by the older cars with dual chargers onboard
(3) The corded mobile connector is based on the older 1st generation UMC and can supply 40A

 

[ajdelange]

Corrections to Corrections: The wall charger can be set for 80A which it can apportion between itself and multiple chargers slaved to it. The most an X, equipped with a 3-module OBC, can draw is 72A. That's why I listed 72A.

Does anyone know how long the cable (to the car) is?

 

[Rocky_H]

The most an X, equipped with a 3-module OBC, can draw is 72A. That's why I listed 72A.

That is a limitation of some models of the vehicles and how much of the wall connector's power they can use. Don't list it as a maximum limitation of the wall connector. Then you might as well have not listed anything above 32A for any of them because some models can only pull 32A with its onboard charger.

 

[ajdelange]

I guess you could read it that way. The point is that if you set the wall charger's switch to the maximum allowable capacity of the charger (80 A) a triple module X will only get 72 because that's the most its OBC can handle. OTOH a double module X can only take 48. But no X (that I know of can get more than 32 A out of the charger supplied with the car nor more than 40 from the corded charger or the new plugin wall unit.

 

[gnuarm]

Just to be clear for people reading this thread, Tesla has made model S cars that can charge at 80 amps from the HPWC. That's why the HPWC can provide up to 80 amps.

 

[ajdelange]

They made it 80A so it can serve a combined load of 80A be that from 1 S drawing 80 or two X's drawing 40 each or....

 

[Bob Denny]

Just placed an order for a new X. Without starting a new thread, this seems like the place to ask. I understand the Model X is limited to 30 Amps charging. Since the NEMA 15-40 can supply 30, then for the X what do I gain with a Tesla Wall Charger on a 60 A circuit? Also are there different adapters for the NEMA? Is the one that I'll get with my new X capable of supplying the 30 amps that the X is limited to? ALl of the acronyms and thingies I see talked about here mean nothing to me. Maybe someday I'll know about them but really I just want to drive my car and charge as reasonably fast as I can at home. A 10% difference between the wall charger and the NEMA 15-40 would not excite me.

 

[Webeevdrivers]

Just placed an order for a new X. Without starting a new thread, this seems like the place to ask. I understand the Model X is limited to 30 Amps charging. Since the NEMA 15-40 can supply 30, then for the X what do I gain with a Tesla Wall Charger on a 60 A circuit? Also are there different adapters for the NEMA? Is the one that I'll get with my new X capable of supplying the 30 amps that the X is limited to? ALl of the acronyms and thingies I see talked about here mean nothing to me. Maybe someday I'll know about them but really I just want to drive my car and charge as reasonably fast as I can at home. A 10% difference between the wall charger and the NEMA 15-40 would not excite me.

Good afternoon. The model X, like all new Tesla X S and AWD 3's, can charge at a rate of 48 amps with the wall charger. Hence the need for a 60 amp circuit. The mobile connector that comes with the car can only provide max 32 amps so all that is technically needed is a 40 amp circuit. If you have a 60 amp circuit you can buy a Tesla Wall charger and have it hardwire installed and it will provide you the full 48 amps.

Hope that helps.

 

[Bob Denny]

Good afternoon. The model X, like all new Tesla X S and AWD 3's, can charge at a rate of 48 amps with the wall charger. Hence the need for a 60 amp circuit. The mobile connector that comes with the car can only provide max 32 amps so all that is technically needed is a 40 amp circuit. If you have a 60 amp circuit you can buy a Tesla Wall charger and have it hardwire installed and it will provide you the full 48 amps. Hope that helps.

Oh! I wasn't aware that the X can charge at 48 amps. Then yeah, it would definitely be worth the wall charger. THANK YOU!!.