# 32 amps vs 40amps



## Mudog101

Hey guys I just picked a model 3 and love it so far. Can anyone with real life experience tell me the difference in mileage gained from charging at 40 amps vs 32. So far I'm using the name 14 50 outlet running the spare cable tesla gavegetting 30 miles an hour . Thinking about getting a permanent solution but don't know if 8 amps are worth the price tag. Any info would be great. 

Thanks


----------



## Michael Russo

Mudog101 said:


> Hey guys I just picked a model 3 and love it so far. Can anyone with real life experience tell me the difference in mileage gained from charging at 40 amps vs 32. So far I'm using the name 14 50 outlet running the spare cable tesla gavegetting 30 miles an hour . Thinking about getting a permanent solution but don't know if 8 amps are worth the price tag. Any info would be great.
> 
> Thanks


Welcome to the forum and congrats!
Hope you're game to share at least a pic of your nice new set of wheels here:
https://teslaownersonline.com/threads/members-delivery-photos-thread-no-chatter.5335/

To your question, I think longtime T≡SLA owner & expert @AEDennis ought to be able to address your question as I remember he's done both on his new Model 3!


----------



## Phil Kulak

Well, it's all linear. So just solve:

32/30 = 40/x

and you should get about 38mph.


----------



## Scuffers

I have a question.

As people actually have their Model 3's now, are the on-board chargers 40 or 48A?

I realise the supplied UMC's are limited, but what about the actual cars? if you plug them into a Tesla wall connector capable of 48A (or more) what do they charge at? - I'm assuming they have the same 11Kw charger on-board as the S&X but would like some definitive answer.


----------



## SoFlaModel3

Mudog101 said:


> Hey guys I just picked a model 3 and love it so far. Can anyone with real life experience tell me the difference in mileage gained from charging at 40 amps vs 32. So far I'm using the name 14 50 outlet running the spare cable tesla gavegetting 30 miles an hour . Thinking about getting a permanent solution but don't know if 8 amps are worth the price tag. Any info would be great.
> 
> Thanks


It's really a question of your daily commute. For instance, I drive ~75 miles/day, so 32A charges my car in about 2.5 hours. My car generally sits at home for ~10 hours if not more and in Florida our electrical costs are not variable so I have no perk for quicker / off peak charging. Thus 32A is all I need!


----------



## garsh

Scuffers said:


> As people actually have their Model 3's now, are the on-board chargers 40 or 48A?


48 amps.
I believe @TrevP was the one who posted a picture of a Model 3 plugged into a wall connector, and the car's screen showed that it was pulling 48 amps.


----------



## sajakh

Confirmed it pulls max 48 A at roughly 34 miles/hr.


----------



## Love

The right question to be asking is: Which one of these cables will get me back out driving my Model 3 quicker? 

EDIT: Also, welcome to the forum!


----------



## 2170pwr

I picked up a Tesla CMC (not UMC) from eBay. Tesla sold them for a while and I found one new for $250. It has a fixed nema 14-50 plug that I can use to charge my Model 3 at 40 A at home and keep the UMC provided by Tesla in the frunk of my car just in case I need to do some AC charging while on the road.


----------



## Dan Detweiler

Either way, you should be able to fully recharge overnight...and to be honest, you won't be fully charging on a regular basis anyway. Probably more like 20-50% on a daily basis so it is pretty negligible the benefits of one over the other. I am installing a HPWC (Tesla High Power Wall Charger) more so I don't have to use the portable one that comes with the car on a regular basis. I can keep in the car so it is ready to go when I charge on the road.

Dan


----------



## 2170pwr

Scuffers said:


> I have a question.
> 
> As people actually have their Model 3's now, are the on-board chargers 40 or 48A?
> 
> I realise the supplied UMC's are limited, but what about the actual cars? if you plug them into a Tesla wall connector capable of 48A (or more) what do they charge at? - I'm assuming they have the same 11Kw charger on-board as the S&X but would like some definitive answer.


48 amps. But if you are using a NEMA 14-50 your circuit is likely a 50 amp circuit so you are limited to 40 amps continues current ( if you use the old umc, or in you put the Tesla wall charger on this circuit). If you use the provided umc you are limited to 32 amps. You can get 48 amps if you have both a 60 amp circuit and you use a wall charger capable of charging at this current. 
Clear as mud?

Truthfully if you are charging over night it doesn't really matter unless you have a very long daily commute.


----------



## NJturtlePower




----------



## Dogwhistle

If you already have a working 240V system set up to charge your car, it probably won’t be worth paying to upgrade it, you won’t notice much difference the way most people use their cars. But if your were doing a new install, sure do a 48A HPWC!


----------



## MelindaV

Dogwhistle said:


> But if your were doing a new install, sure do a 48A HPWC


which would be a 60A circuit. (with 48A available)


----------



## AEDennis

To answer the questions visually... YMMV (state of charge, etc.)

As @Michael Russo remembered... I've posted these pictures on tweets since December...

48 Amps on LR at home HPWC (It's wired to go to 56 for our S or Roadster. Too costly to get the 100A wire to run dual chargers on the S, so went to 70A wire)

Untitled by Dennis Pascual, on Flickr

32 Amps on UMC (at the office, so commercial 208V feed, not 240V)

Untitled by Dennis Pascual, on Flickr

40 Amps on UMC (at the office, so commercial 208V feed, not 240V)

Untitled by Dennis Pascual, on Flickr

Aside from running the UMC at home at 240V, what's also missing in my common charging is 30A/240V from my (about two weeks away) six year old Couloumb Technologies (ChargePoint now) CT-500. That gets similar recovery as 32A/208V.

One thing to note is how bad the Vampire Drain is on the Model 3 vs a Model S since the car doesn't sleep. It does not have the setting that I like to use on our S to have the systems sleep until woken up. It's always connected at the moment.


----------



## Scuffers

Thanks for the pictures etc.

So, effectively, they have the same chargers as the S&X then (and as we have yet to see a NON-LR Model 3, we still don't actually know 100% what it will have?)

Personally, I would love to have the equivalent to the old S dual charger option, I have 100A 3 phase avaliable, so running 32A 3 phase would get me ~22Kw charging.

Also, a lot of public level 2 chargers here are 32A 3 phase.

Mind you, according to Tesla, I still have another year to wait for my M3 (UK), so who knows what will have changed?


----------



## AEDennis

Scuffers said:


> Thanks for the pictures etc.
> 
> So, effectively, they have the same chargers as the S&X then (and as we have yet to see a NON-LR Model 3, we still don't actually know 100% what it will have?)
> 
> Personally, I would love to have the equivalent to the old S dual charger option, I have 100A 3 phase avaliable, so running 32A 3 phase would get me ~22Kw charging.
> 
> Also, a lot of public level 2 chargers here are 32A 3 phase.
> 
> Mind you, according to Tesla, I still have another year to wait for my M3 (UK), so who knows what will have changed?


I think that Tesla is trying to "motivate" M3 owners that charge publicly to use DCFC (and prefer that it be the Tesla Supercharger network.)


----------



## Scuffers

that's great unless you live somewhere that SC network simply does not cover.

In the UK, they are few and far between, and as 99% of the places I go daily have 3 phase, it would suit my needs better, being able to charge at ~90mi/Hr would be terrific.


----------



## Love

2170pwr said:


> I picked up a Tesla CMC (not UMC) from eBay. Tesla sold them for a while and I found one new for $250. It has a fixed nema 14-50 plug that I can use to charge my Model 3 at 40 A at home and keep the UMC provided by Tesla in the frunk of my car just in case I need to do some AC charging while on the road.


That's a great find. My wife and I want to do the same thing for the same exact reason, but I'd been searching ebay for gen 1 UMC's... sounds like I need to look for the CMC. Thank you for the information!


----------



## Mudog101

Thanks for the replies. I think I will stick with the mobile charger until I find a used one of ebay. Was just trying to justify the cost for 8 more miles an hour. Lol


----------



## SoFlaModel3

Here is my current charge rate with the 32A UMC on my Nema 14-50 outlet.

It's a less than 1% use case where 30 miles of charge range per hour isn't going to be enough. My daily commute is 75 miles roundtrip. The only situation I can think of is a concert on a weeknight which would add another 75 miles roundtrip. Still that's 150 miles of range used in the day. We get home at 12 am and I leave the house for work at 7 am. I have 7 hours to charge and would only need 5. Also, the next day I'd only need my 75 miles anyway, so technically I'm good without even charging at all to make it another day. On any normal day (99.9% of the time), I just need 2.5-3 hours to charge. I love range!


----------



## AEDennis

AEDennis said:


> To answer the questions visually... YMMV (state of charge, etc.)
> 
> As @Michael Russo remembered... I've posted these pictures on tweets since December...
> 
> 48 Amps on LR at home HPWC (It's wired to go to 56 for our S or Roadster. Too costly to get the 100A wire to run dual chargers on the S, so went to 70A wire)
> 
> Untitled by Dennis Pascual, on Flickr
> 
> 32 Amps on UMC (at the office, so commercial 208V feed, not 240V)
> 
> Untitled by Dennis Pascual, on Flickr
> 
> 40 Amps on UMC (at the office, so commercial 208V feed, not 240V)
> 
> Untitled by Dennis Pascual, on Flickr
> 
> Aside from running the UMC at home at 240V, what's also missing in my common charging is 30A/240V from my (about two weeks away) six year old Couloumb Technologies (ChargePoint now) CT-500. That gets similar recovery as 32A/208V.
> 
> One thing to note is how bad the Vampire Drain is on the Model 3 vs a Model S since the car doesn't sleep. It does not have the setting that I like to use on our S to have the systems sleep until woken up. It's always connected at the moment.


Ok... Because I can't leave well enough alone...

Here is the car charging on the six year old Couloumb Technologies (ChargePoint now) CT-500...

IMG_5793.PNG by Dennis Pascual, on Flickr

Slightly better rate than my 32A/208V charge...


----------



## Grrrreg

SoFlaModel3 said:


> Here is my current charge rate with the 32A UMC on my Nema 14-50 outlet.
> 
> It's a less than 1% use case where 30 miles of charge range per hour isn't going to be enough. My daily commute is 75 miles roundtrip. The only situation I can think of is a concert on a weeknight which would add another 75 miles roundtrip. Still that's 150 miles of range used in the day. We get home at 12 am and I leave the house for work at 7 am. I have 7 hours to charge and would only need 5. Also, the next day I'd only need my 75 miles anyway, so technically I'm good without even charging at all to make it another day. On any normal day (99.9% of the time), I just need 2.5-3 hours to charge. I love range!
> 
> View attachment 5712


I hope this isn't a dumb question but on your NEMA 14-50 receptacle, you must have a 40 amp breaker, therefore 32 amp charging. Some NEMA 14-50 receptacles have a 50 amp breaker, so 40 amp charging is available. How does the mobile charger know the circuit capacity? I know the HPWC has dip switch settings but you wouldn't want to change settings on a mobile charger. Or is it the same as HPWC?


----------



## SoFlaModel3

Grrrreg said:


> I hope this isn't a dumb question but on your NEMA 14-50 receptacle, you must have a 40 amp breaker, therefore 32 amp charging. Some NEMA 14-50 receptacles have a 50 amp breaker, so 40 amp charging is available. How does the mobile charger know the circuit capacity? I know the HPWC has dip switch settings but you wouldn't want to change settings on a mobile charger. Or is it the same as HPWC?


I have a 50A breaker on my Nema 14-50, but the new UMC is limited to 32A.


----------



## garsh

SoFlaModel3 said:


> I have a 50A breaker on my Nema 14-50, but the new UMC is limited to 32A.


That did not answer his question. Read again. 

I *think* the answer is you configure the car to limit it, but hopefully an owner can answer for sure.


----------



## SoFlaModel3

garsh said:


> That did not answer his question. Read again.
> 
> I *think* the answer is you configure the car to limit it, but hopefully an owner can answer for sure.


Whoops - yes on the charging screen you can set max Amps for charging!


----------



## Grrrreg

So now I understand that UMC is limited to 32A. But here’s my situation. At home I will start out on a 30A circuit and at work I have a 60A circuit available. So I will charge at 32A at work but what limits the current to 24A at home? If it’s a setting on the touch screen then it would have to be changed for each location?


----------



## garsh

Grrrreg said:


> So now I understand that UMC is limited to 32A. But here's my situation. At home I will start out on a 30A circuit and at work I have a 60A circuit available. So I will charge at 32A at work but what limits the current to 24A at home? If it's a setting on the touch screen then it would have to be changed for each location?


If you use a Wall Connector at home, you can program it to provide whatever current the circuit will support. But if your just using the Mobile Connector at both places, then yes, I think you need to change the setting in the car as you switch from one place to the next.

It would be nice if the car can "remember" the setting for a particular place, but I haven't heard anybody describe that kind of functionality.


----------



## Grrrreg

garsh said:


> If you use a Wall Connector at home, you can program it to provide whatever current the circuit will support. But if your just using the Mobile Connector at both places, then yes, I think you need to change the setting in the car as you switch from one place to the next.
> 
> It would be nice if the car can "remember" the setting for a particular place, but I haven't heard anybody describe that kind of functionality.


Yeah I was hoping not to have to grunt up $700.00 for that. I forsee a lot of tripped breakers when my wife forgets to change the setting.


----------



## AEDennis

SoFlaModel3 said:


> Whoops - yes on the charging screen you can set max Amps for charging!





Grrrreg said:


> So now I understand that UMC is limited to 32A. But here's my situation. At home I will start out on a 30A circuit and at work I have a 60A circuit available. So I will charge at 32A at work but what limits the current to 24A at home? If it's a setting on the touch screen then it would have to be changed for each location?





garsh said:


> If you use a Wall Connector at home, you can program it to provide whatever current the circuit will support. But if your just using the Mobile Connector at both places, then yes, I think you need to change the setting in the car as you switch from one place to the next.
> 
> It would be nice if the car can "remember" the setting for a particular place, but I haven't heard anybody describe that kind of functionality.


I'll dial down the charge rate at home tonight... I have a 30A J1772... I'll manually set it to 24A and see if it sees it at 24A the next time I charge here...


----------



## garsh

Grrrreg said:


> Yeah I was hoping not to have to grunt up $700.00 for that.


Not ideal, but you could purchase a J1772 EVSE limited (or configurable) to 24 amps or less for your house. That would require you to use the J1772 adapter that came with your car, which is the big downside, but then you wouldn't have to worry about remembering to change the charge setting in the car. You could leave the adapter connected to the EVSE if you don't plan on charging elsewhere. Like I said, it's not an ideal solution.

I managed to snag a 16 amp Duosida charger for $155, but I had been hunting for a good deal for a while. You can find plenty of 16 amp EVSEs for under $300, and I think Amazon even shows a couple for $199.

Amazon: EVSE


----------



## NJturtlePower

SoFlaModel3 said:


> I have a 50A breaker on my Nema 14-50, but the new UMC is limited to 32A.


This is my planned setup as well.

Do we know why Tesla changed the Gen2 UMC to limit at 32A and not the 40A previously available by the car and the chargers?

Trying to upsell people to the HPWC's?


----------



## garsh

NJturtlePower said:


> Do we know why Tesla changed the Gen2 UMC to limit at 32A and not the 40A previously available by the car and the chargers?


Not with certainty, but my guess is "cost reduction". They're including one of these with every Model 3 sold, so they wanted a version that was less expensive to make.


----------



## MelindaV

AEDennis said:


> I'll dial down the charge rate at home tonight... I have a 30A J1772... I'll manually set it to 24A and see if it sees it at 24A the next time I charge here...


Does the car not automatically sense the Amps and set a recommended rate?


----------



## MelindaV

garsh said:


> Not with certainty, but my guess is "cost reduction". They're including one of these with every Model 3 sold, so they wanted a version that was less expensive to make.


I'd also add, I think the cord/adaptor set-up is a little more refined on the 32A vs the original UMC. There could be limitations with the new style connection point that limited it.


----------



## AEDennis

MelindaV said:


> Does the car not automatically sense the Amps and set a recommended rate?


It does... And goes at Max 30A .The challenge is to simulate the set up requesting a manual dial down and whether the setting sticks (GPS) The Model S and Roadster does this... Haven't tested with 3... Until now


----------



## AEDennis

MelindaV said:


> I'd also add, I think the cord/adaptor set-up is a little more refined on the 32A vs the original UMC. There could be limitations with the new style connection point that limited it.


Many have mentioned that Tesla was pushing limits running 40A considering the gauge of the wire in the UMC. Canada forced Tesla to software derate the ones in Canada to 32A (Gen 1)


----------



## LucyferSam

Grrrreg said:


> Yeah I was hoping not to have to grunt up $700.00 for that. I forsee a lot of tripped breakers when my wife forgets to change the setting.


I'll be interested to hear when you test it out, but I think it will depend on the wire run. At least in the S, it will detect if there is too much voltage drop in the line as it ramps up the current and limit the charge current based on that voltage drop. What that means practically is that if your 30A breaker is sized correctly, there is a decent chance the car will limit it's draw before it trips the breaker.


----------



## AEDennis

Grrrreg said:


> So now I understand that UMC is limited to 32A. But here's my situation. At home I will start out on a 30A circuit and at work I have a 60A circuit available. So I will charge at 32A at work but what limits the current to 24A at home? If it's a setting on the touch screen then it would have to be changed for each location?





AEDennis said:


> It does... And goes at Max 30A .The challenge is to simulate the set up requesting a manual dial down and whether the setting sticks (GPS) The Model S and Roadster does this... Haven't tested with 3... Until now





AEDennis said:


> I'll dial down the charge rate at home tonight... I have a 30A J1772... I'll manually set it to 24A and see if it sees it at 24A the next time I charge here...


I didn't get to it at the house last night... So, simulating at the office... Which actually works better 'cause I can plug back in the afternoon after lunch and see if it holds the changed Amperage...

Some pictures...

Plugging in... Using my adapted to J1772 Gen 1 UMC (runs at 40A (outlet is 208V/40A))

IMG_20180313_073813 by Dennis Pascual, on Flickr

J1772 with Tesla adapter...

IMG_20180313_073844 by Dennis Pascual, on Flickr

Connected

IMG_20180313_073847 by Dennis Pascual, on Flickr

Auto-senses 40A

IMG_20180313_073910 by Dennis Pascual, on Flickr

Dialed down to 30A

IMG_20180313_073923 by Dennis Pascual, on Flickr

(this will let us test the same location with the 32A UMC v 2 that the Model 3 came with later)

Performance at 30A isn't bad...

Screenshot_20180313-075249.png by Dennis Pascual, on Flickr

This also simulates what you would likely see as a charge rate from a public Level 2 as many run at 30A and not 40A (or even 32A)... Though some old Blinks were derated to 24A...

More pictures after lunch...


----------



## AEDennis

AEDennis said:


> I didn't get to it at the house last night... So, simulating at the office... Which actually works better 'cause I can plug back in the afternoon after lunch and see if it holds the changed Amperage...
> 
> Some pictures...
> 
> Plugging in... Using my adapted to J1772 Gen 1 UMC (runs at 40A (outlet is 208V/40A))
> 
> IMG_20180313_073813 by Dennis Pascual, on Flickr
> 
> J1772 with Tesla adapter...
> 
> IMG_20180313_073844 by Dennis Pascual, on Flickr
> 
> Connected
> 
> IMG_20180313_073847 by Dennis Pascual, on Flickr
> 
> Auto-senses 40A
> 
> IMG_20180313_073910 by Dennis Pascual, on Flickr
> 
> Dialed down to 30A
> 
> IMG_20180313_073923 by Dennis Pascual, on Flickr
> 
> (this will let us test the same location with the 32A UMC v 2 that the Model 3 came with later)
> 
> Performance at 30A isn't bad...
> 
> Screenshot_20180313-075249.png by Dennis Pascual, on Flickr
> 
> This also simulates what you would likely see as a charge rate from a public Level 2 as many run at 30A and not 40A (or even 32A)... Though some old Blinks were derated to 24A...
> 
> More pictures after lunch...


Back from lunch...

OK... Using the same 40A UMC this morning...

Pulled up to the plug, charged it...

Screenshot_20180313-131348.png by Dennis Pascual, on Flickr

IMG_20180313_131357 by Dennis Pascual, on Flickr

Looks like it kept the setting...

Next time I take the car and charge, I'll try with the new UMC and see if it still stays at 30A...

(Probably won't be until Thursday, I'm carpooling with my wife tomorrow.)


----------



## Grrrreg

LucyferSam said:


> I'll be interested to hear when you test it out, but I think it will depend on the wire run. At least in the S, it will detect if there is too much voltage drop in the line as it ramps up the current and limit the charge current based on that voltage drop. What that means practically is that if your 30A breaker is sized correctly, there is a decent chance the car will limit it's draw before it trips the breaker.


First I'd like to thank everyone. This forum is an amazing resource.
I think the water is becoming less murky. So the on-board system is basically measuring the conductor gauge in the circuit based on Ohms law. It's genius. But does risk nuisance tripping. That's what the max charge setting is for. I see @AEDennis pulling 40A off a 40A circuit. If this is in fact what is happening he would be able to set max charge to 48A and the system would keep it about 40A based on Ohms law. So to play by the rules I would still need to set max charge for each location at 80% circuit capacity.
Am I looking at this right, or is the water getting murkier?


----------



## AEDennis

Grrrreg said:


> First I'd like to thank everyone. This forum is an amazing resource.
> I think the water is becoming less murky. So the on-board system is basically measuring the conductor gauge in the circuit based on Ohms law. It's genius. But does risk nuisance tripping. That's what the max charge setting is for. I see @AEDennis pulling 40A off a 40A circuit. If this is in fact what is happening he would be able to set max charge to 48A and the system would keep it about 40A based on Ohms law. So to play by the rules I would still need to set max charge for each location at 80% circuit capacity.
> Am I looking at this right, or is the water getting murkier?


That is incorrect...

The UMC pulls 40A off a 50A circuit... That's NEMA 14-50...

I would pull 32A off a 40A circuit.


----------



## garsh

AEDennis, I need some clarification on your test to make sure I understand.



AEDennis said:


> I'll dial down the charge rate at home tonight... I have a 30A J1772... I'll manually set it to 24A and see if it sees it at 24A the next time I charge here...





AEDennis said:


> The challenge is to simulate the set up requesting a manual dial down and whether the setting sticks (GPS) The Model S and Roadster does this... Haven't tested with 3... Until now


In particular, I want to know if the manual setting only applies to that one charger. If I go to some other location, will it once again default to max possible? It's not clear to me that your test checked that. Did you charge somewhere else at 40 amps or more in between the two other tests?


AEDennis said:


> Auto-senses 40A
> Dialed down to 30A





AEDennis said:


> Back from lunch...
> OK... Using the same 40A UMC this morning...
> Pulled up to the plug, charged it...
> Looks like it kept the setting...


Can you confirm that the car charges at 40 amps when:

you use the same UMC at a different location, and
when you use a different UMC at a different location, or
when you use a wall connector somewhere
That's a lot of variables. I'm hoping to figure out if the car just stays at 30 amps now, or if the setting is tied to a particular MC (via charger serial number maybe?), or tied to a particular location (GPS based?).


----------



## AEDennis

garsh said:


> AEDennis, I need some clarification on your test to make sure I understand.
> 
> In particular, I want to know if the manual setting only applies to that one charger. If I go to some other location, will it once again default to max possible? It's not clear to me that your test checked that. Did you charge somewhere else at 40 amps or more in between the two other tests?


The Roadster and Model S, behave in this manner. It will auto-sense and try to charge the car at the highest available amperage. If the Model S senses a wiring issue, it will dial it down. I am trying to simulate tests with Model 3 to make sure that it does the same thing. It uses GPS locations to set amperage and the like for each site. In my test, I did not go anywhere else to charge, just lunch and back to the same spot. It kept the setting (which is what an S or Roadster would do.)



garsh said:


> Can you confirm that the car charges at 40 amps when:
> 
> you use the same UMC at a different location, and
> when you use a different UMC at a different location, or
> when you use a wall connector somewhere
> That's a lot of variables. I'm hoping to figure out if the car just stays at 30 amps now, or if the setting is tied to a particular MC (via charger serial number maybe?), or tied to a particular location (GPS based?).


I can confirm that the same UMC has and continues to charge at 40A. It uses GPS, and as such will adapt to whatever highest setting I will have, EXCEPT for areas that I override it. I want to test to see if it goes to 30A on the UMC 2nd Gen next time I charge at work...


----------



## Grrrreg

AEDennis said:


> That is incorrect...
> 
> The UMC pulls 40A off a 50A circuit... That's NEMA 14-50...
> 
> I would pull 32A off a 40A circuit.


 Sorry I misunderstood. In the first shot of your touch screen it shows charging 40/40 A. 
You are saying it was not really charging only sensing?

In the second shot of your touch screen it shows charging 30/40 A. 
When you say it was dialled back, was it dialled back by the system or by you?


----------



## AEDennis

Grrrreg said:


> Sorry I misunderstood. In the first shot of your touch screen it shows charging 40/40 A.
> You are saying it was not really charging only sensing?
> 
> In the second shot of your touch screen it shows charging 30/40 A.
> When you say it was dialled back, was it dialled back by the system or by you?


I dialled it back manually to do what was requested (to see if we can have the car charge at a lower Amperage than what is auto-sensed...)


----------



## Grrrreg

AEDennis said:


> I dialled it back manually to do what was requested (to see if we can have the car charge at a lower Amperage than what is auto-sensed...)


I don't want this to turn into a pain for you and I appreciate your time and effort. But I am clearly missing something. You said the outlet is 208V/40A. The first pic of your touch screen shows the car charging at 40A on that 40A circuit. Is it really a 50A circuit? And does the touch screen say X/40 because of the gen 1 UMC limit at 40A?


----------



## AEDennis

Grrrreg said:


> I don't want this to turn into a pain for you and I appreciate your time and effort. But I am clearly missing something. You said the outlet is 208V/40A. The first pic of your touch screen shows the car charging at 40A on that 40A circuit. Is it really a 50A circuit? And does the touch screen say X/40 because of the gen 1 UMC limit at 40A?


The circuit is 50A. The UMC sees it as 40A usable and good. It's a 240V/50A NEMA 14-50 outlet... If I typed incorrectly that's because I usually look at what is usable for my car, and since it's a clean run I can use 80% of the 50A circuit; i.e. 40A.

That being said...

Last update on this test at 30A...

Using Gen 2 UMC (the one that came with the car and limited BY DESIGN to 32A on a 50A Outlet)

IMG_20180314_085514 by Dennis Pascual, on Flickr

IMG_20180314_085506 by Dennis Pascual, on Flickr

You can see that the car is still charging at 30A (which is what it will assume because of GPS) even though the UMC can support up to 32A on the 50A NEMA 14-50 OUTLET.

IMG_20180314_085545 by Dennis Pascual, on Flickr

Lastly, a screenshot from the App after I've stepped away for a while and right before I responded to this post...

Screenshot_20180314-093144.png by Dennis Pascual, on Flickr

...now back to work... (the one that pays the bills ;-) )


----------



## Grrrreg

AEDennis said:


> The circuit is 50A. The UMC sees it as 40A usable and good. It's a 240V/50A NEMA 14-50 outlet... If I typed incorrectly that's because I usually look at what is usable for my car, and since it's a clean run I can use 80% of the 50A circuit; i.e. 40A.
> 
> That being said...
> 
> Last update on this test at 30A...
> 
> Using Gen 2 UMC (the one that came with the car and limited BY DESIGN to 32A on a 50A Outlet)
> 
> IMG_20180314_085514 by Dennis Pascual, on Flickr
> 
> IMG_20180314_085506 by Dennis Pascual, on Flickr
> 
> You can see that the car is still charging at 30A (which is what it will assume because of GPS) even though the UMC can support up to 32A on the 50A NEMA 14-50 OUTLET.
> 
> IMG_20180314_085545 by Dennis Pascual, on Flickr
> 
> Lastly, a screenshot from the App after I've stepped away for a while and right before I responded to this post...
> 
> Screenshot_20180314-093144.png by Dennis Pascual, on Flickr
> 
> ...now back to work... (the one that pays the bills ;-) )


Thanks, that clears things up. One more question and I will stop harassing you. I have a 30A circuit. If I plug the gen 2 UMC in it what will the charge rate be? Will it try to charge close to 30A or will it sense the 30A circuit and reduce to 24A?


----------



## AEDennis

Grrrreg said:


> Thanks, that clears things up. One more question and I will stop harassing you. I have a 30A circuit. If I plug the gen 2 UMC in it what will the charge rate be? Will it try to charge close to 30A or will it sense the 30A circuit and reduce to 24A?


Is the outlet a NEMA 14-50 with a 30A circuit or is it a NEMA 14-30 (in which case buy the adapter on the Tesla site)....

If it's the latter, it should sense... If the former it will try at 40A first... So, safer to dial it down at the beginning .

Bottom line, match the outlet to size/gauge of wire so that it works best.

Dennis


----------



## Grrrreg

AEDennis said:


> Is the outlet a NEMA 14-50 with a 30A circuit or is it a NEMA 14-30 (in which case buy the adapter on the Tesla site)....
> 
> If it's the latter, it should sense... If the former it will try at 40A first... So, safer to dial it down at the beginning .
> 
> Bottom line, match the outlet to size/gauge of wire so that it works best.
> 
> Dennis


It's NEMA 14-30. so will it try near 30A or automatically go to 80% (24A)? after I get the right adapter


----------



## AEDennis

Grrrreg said:


> It's NEMA 14-30. so will it try near 30A or automatically go to 80% (24A)? after I get the right adapter


Exactly...

https://shop.tesla.com/us/en/product/vehicle-accessories/model-3-nema-adapters.html?sku=1099345-00-C

That's a link to the adapters available for Model 3 (2nd Gen UMC)

From that page -

Tesla 2nd GEN UMC Charging Rate - Model 3 by Dennis Pascual, on Flickr


----------



## garsh

Grrrreg said:


> It's NEMA 14-30. so will it try near 30A or automatically go to 80% (24A)? after I get the right adapter





AEDennis said:


> Exactly...


Grrrreg asked a question - I think you read it a little too quickly. 

When using the Tesla 14-30 adapter, does the car *automatically* charge at 24 amps when using that adapter, without requiring setting anything up on the touchscreen?


----------



## AEDennis

garsh said:


> Grrrreg asked a question - I think you read it a little too quickly.
> 
> When using the Tesla 14-30 adapter, does the car *automatically* charge at 24 amps when using that adapter, without requiring setting anything up on the touchscreen?


YES, that's what it does with NEMA 14-50 adapter... (if clean runs it at 40A), etc... So, a NEMA 14-30 runs clean at 24A, etc..


----------



## c2c

NJturtlePower said:


> This is my planned setup as well.
> 
> Do we know why Tesla changed the Gen2 UMC to limit at 32A and not the 40A previously available by the car and the chargers?
> 
> Trying to upsell people to the HPWC's?


OK, I am not that kind of engineer. But maybe someone who knows something can fill in some gaps.
At "https://teslamotorsclub(dot)com/tmc/threads/ground-fault-protection-a-new-complication-for-ev-charging.88338/" is a discussion that involves a new "National Electric Code" (NEC) with regards to 2 phase lines in homes.
*"You know the National Electric Code is changing so that ground fault protection is required for 208/240 outlets" *
Is from that link. NEC 2017 requires a Ground Fault Protection at the panel and at the outlet. So if you use a UMC, there is a chance your charging will get the GFPs fighting, and you stop charging.
It is rumored that Tesla will be suggesting that the Wall Charger is the way to do serious home charging. The Wall Charger does not use an outlet, being hard wired in, so it does not need the GFP.
Many states, like my Washington State, have adopted NEC 2017 within the last 12 months, so by the time I get around to wiring my garage, that Gen 1 UMC I got in January for a steal of $300 will not provide the 40 amps I was hoping for.
And more fuzzy memory makes me say that at 32 Amps or less the GFP might not be so rigidly enforced.
But, PLEASE DO NOT BET ANYTHING ON MY MUSINGS.


----------



## AEDennis

Hoping that @c2c is mistaken... Since I have a bunch of NEMA 14-50 in my house...

Here's the charger after all testing today...

IMG_20180314_135557 by Dennis Pascual, on Flickr

I had to manually intervene to bump up the Amperage as the 30A setting still overrode it.

I drove so close to the office that I couldn't get a screenshot from the App in time, so I had to go past 90% to get it going again and show the App screen...

Screenshot_20180314-143802.png by Dennis Pascual, on Flickr


----------



## c2c

AEDennis said:


> Hoping that @c2c is mistaken... Since I have a bunch of NEMA 14-50 in my house.


I also REALLY hope I am mistaken.


----------



## garsh

AEDennis said:


> Hoping that @c2c is mistaken... Since I have a bunch of NEMA 14-50 in my house...


Even if the electrical codes change, existing wiring is always grandfathered in. You won't have to change anything.

There are still several old houses in Pittsburgh that still have knob-and-tube wiring from the early 1900's. Pretty damn dangerous nowadays, but allowed until you renovate.


----------



## Bill Treloar

NJturtlePower said:


> View attachment 5695


Thanks for this! With the long-range battery, will my car charge at the higher rate even if I use the cable that came with the car? Or is that cable limited to 32A?


----------



## Bill Treloar

Lovesword said:


> That's a great find. My wife and I want to do the same thing for the same exact reason, but I'd been searching ebay for gen 1 UMC's... sounds like I need to look for the CMC. Thank you for the information!


For a newbie, what's UMC and CMC?


----------



## AEDennis

Bill Treloar said:


> Thanks for this! With the long-range battery, will my car charge at the higher rate even if I use the cable that came with the car? Or is that cable limited to 32A?


The car will charge at the lower of the combination of supply or charger speed. So if your car is plugged into an 80a station, it will go as fast as 48a. If you're plugged into the UMC that comes with the car it will only go as fast as 32a at it's maximum, assuming the outlet supports that .



Bill Treloar said:


> For a newbie, what's UMC and CMC?


I don't know CMC in this context .HPWC or WC were the Tesla specific models of EVSE (electric vehicle supply equipment) .


----------



## MelindaV

AEDennis said:


> Hoping that @c2c is mistaken... Since I have a bunch of NEMA 14-50 in my house...


FYI... here's a map that IDs which version of NEC each state has adopted


----------



## Love

Bill Treloar said:


> For a newbie, what's UMC and CMC?


The CMC is the "corded mobile connector" (https://shop.tesla.com/us/en/produc...corded-mobile-connector.html?sku=1106293-00-A)... it has a dedicated (not changeable) 240 plug (NEMA 14-50) that sits flush to the wall as it hangs from the outlet and can charge the Model 3 up to 40A like the UMC (universal mobile connector) that comes with the Model S and X (generation 1). The generation 2 UMC that comes with the Model 3 can "only" charge up to 32A. (https://shop.tesla.com/us/en/produc...mobile-connector-bundle.html?sku=1139373-00-A)

EDIT: to add a link to a picture of my CMC
https://teslaownersonline.com/threads/my-model-3-heav3n.5943/page-5#post-81018


----------



## tipton

one question along the line of this thread

the Gen 1 mobile connector from my understanding has a limit of 40 amps. if you use this with the model 3 will you get a higher charge rate than the Gen 2 connector that comes with the model 3 on a Nema 14 50 outlet?


----------



## SoFlaModel3

tipton said:


> one question along the line of this thread
> 
> the Gen 1 mobile connector from my understanding has a limit of 40 amps. if you use this with the model 3 will you get a higher charge rate than the Gen 2 connector that comes with the model 3 on a Nema 14 50 outlet?


That is correct, you will get a higher rate of charge. I don't think it's worth your spend unless you were planning to buy an extra UMC anyway.


----------



## tipton

SoFlaModel3 said:


> That is correct, you will get a higher rate of charge. I don't think it's worth your spend unless you were planning to buy an extra UMC anyway.


agreed, but I got a Gen 1 connector for a ridiculous low price of $100 with a Nema 14-50 attachment. So was just trying to figure out if i should keep that to charge with and sell the Gen 2 connector or not. maybe i keep them both. not sure.


----------



## AEDennis

tipton said:


> one question along the line of this thread
> 
> the Gen 1 mobile connector from my understanding has a limit of 40 amps. if you use this with the model 3 will you get a higher charge rate than the Gen 2 connector that comes with the model 3 on a Nema 14 50 outlet?


Yes, see my posts from earlier in this thread - I have both UMCs .

https://teslaownersonline.com/threads/32-amps-vs-40amps.5961/#post-73988



SoFlaModel3 said:


> That is correct, you will get a higher rate of charge. I don't think it's worth your spend unless you were planning to buy an extra UMC anyway.


Bought higher one as the J1772 converted version is more compatible with other OEM EVs.


----------



## AEDennis

tipton said:


> agreed, but I got a Gen 1 connector for a ridiculous low price of $100 with a Nema 14-50 attachment. So was just trying to figure out if i should keep that to charge with and sell the Gen 2 connector or not. maybe i keep them both. not sure.


I think that itsi a better UMC than Gen 2


----------



## c2c

I have a gen 1, a car, and a gen 2. I am one lucky duck.
I keep the 2 in the CAR with the j1772 adapter, so I'm always ready. 
I hang the gen 1 for daily charging, for about 20% faster charging. I got the gen 1 on eBay for $300. Almost unused. Must have been from a totaled S or X.
I got the gen 1 for a now cancelled trip through the wilderness, for RV park to RV park. No regrets.


----------

