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Home charging help

mrau

Authorized Driver
Supporting Member
Nov 12, 2018
441
839
Mid-Michigan
I am interested in the Nema 14-50 for charging at mu in laws. I’m curious what the max rate of charge is on one? I prefer day trips and not over night trips 😉 lol
If you use the UMC that comes with the car and plug it into a 14-50 outlet, then you will charge at 32 amps. The UMC maxes out at 32 amps. You would need a Clippercreek, Juicebox, or Grizzl-E plug-in type chargers to get the full 40 amps.

Here is chart to show different charging miles using the UMC.

Adapter Chart rate.png
 

Gauss Guzzler

Member
Dec 27, 2020
446
552
Thousand Oaks, California
The older Gen2 mobile connector is another that can do 40A but be cautious with any of these. Some 50A outlets are (legally) installed with 40A breakers and wiring so if you go around plugging into other people's outlets you may unknowingly run the circuit at 100% capacity instead of the legal 80% limit. That's surely one of the reasons Tesla reduced the limit to 32A on newer versions.
 
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Schulz1983

Model Y LR AWD: Matte PPF, Vossen HF-1
May 14, 2021
563
371
High Ridge MO
The older Gen2 mobile connector is another that can do 40A but be cautious with any of these. Some 50A outlets are (legally) installed with 40A breakers and wiring so if you go around plugging into other people's outlets you may unknowingly run the circuit at 100% capacity instead of the legal 80% limit. That's surely one of the reasons Tesla reduced the limit to 32A on newer versions.
Tesla’s Gen III charger is a 48 amp unit. 32 amp charges pretty slow in my opinion. Sometimes I limit the car to 32 amp at home as I heard it is more efficient to charge at the lower amperage.
 

F14Scott

Member
Apr 7, 2019
207
344
Houston
Tesla’s Gen III charger is a 48 amp unit. 32 amp charges pretty slow in my opinion. Sometimes I limit the car to 32 amp at home as I heard it is more efficient to charge at the lower amperage.
I don't know your source for the "lower Amperage is more efficient" statement, but the opposite is true, because of the car's 400 Watt hotel load. The higher the power going into the car, proportionally more power goes to charging the battery, so it charges proportionally faster and has less wasted energy powering the computers and the battery conditioner.
 

F14Scott

Member
Apr 7, 2019
207
344
Houston
Also, if you get the wall connector, you can use it with an adapter for J1772 cars. I have two Gen 2 wall connectors intelligently sharing a 60 Amp breaker, one for my wife's TM3 AWD and the other for my MINI SE, using this adapter:


Screenshot_20210515-214117_Amazon Shopping.jpg
 

Schulz1983

Model Y LR AWD: Matte PPF, Vossen HF-1
May 14, 2021
563
371
High Ridge MO
I don't know your source for the "lower Amperage is more efficient" statement, but the opposite is true, because of the car's 400 Watt hotel load. The higher the power going into the car, proportionally more power goes to charging the battery, so it charges proportionally faster and has less wasted energy powering the computers and the battery conditioner.
You are correct. I did some more research and high amp charging on level 2 chargers are approx 95% efficient. The 120 volt charging is showing 80% efficient according to car and driver. I will charge at 48 amp from now on. Thank you for pointing that out. I read the lower amp charging was more efficient when I was researching before buying a Tesla. There was a forum on this website talking about it. I guess I read incorrectly.
 

JoshFalken

Member
Mar 8, 2021
38
28
CLT
I did a 14-50 with a corded mobile connector in lieu of the High Performance Wall Connector so I can easily take the unit with me if I move. I do have experience around electrical wiring and did my setup myself but wanted the portability should I ever need it. I also wanted my daughter to be able to connect their RV while in town. (2 birds, 1 stone) You can’t go wrong with either, just get what works best for you long term.
 

skriefal

Member
Mar 29, 2021
30
26
Utah, USA
You are correct. I did some more research and high amp charging on level 2 chargers are approx 95% efficient. The 120 volt charging is showing 80% efficient according to car and driver. I will charge at 48 amp from now on. Thank you for pointing that out. I read the lower amp charging was more efficient when I was researching before buying a Tesla. There was a forum on this website talking about it. I guess I read incorrectly.

Perhaps you were reading a discussion about impact on battery longevity. There are many claims that a faster charging speed will cause the battery to degrade (range to decrease) quicker. Which is theoretically true - but there isn't likely to be much difference between a 32-amp charge rate and a 48-amp charge rate. Charging 100% on Superchargers, however, may show more battery degradation than if you use a home charger whenever possible. But even then it usually isn't a "night & day" difference.
 

Schulz1983

Model Y LR AWD: Matte PPF, Vossen HF-1
May 14, 2021
563
371
High Ridge MO
Perhaps you were reading a discussion about impact on battery longevity. There are many claims that a faster charging speed will cause the battery to degrade (range to decrease) quicker. Which is theoretically true - but there isn't likely to be much difference between a 32-amp charge rate and a 48-amp charge rate. Charging 100% on Superchargers, however, may show more battery degradation than if you use a home charger whenever possible. But even then it usually isn't a "night & day" difference.
That sounds right. I’m not to worried about battery degradation. When we traveled to Atlanta to get our Y wrapped I ended up charging hopping and never charged over 80% or less anyway. We usually keep vehicles 100k-150k miles and I imagine this one will be the same. When they advance battery tech and we can get longer range in a Y we will upgrade.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,330
11,672
Riverside Co. CA
Perhaps you were reading a discussion about impact on battery longevity. There are many claims that a faster charging speed will cause the battery to degrade (range to decrease) quicker. Which is theoretically true - but there isn't likely to be much difference between a 32-amp charge rate and a 48-amp charge rate. Charging 100% on Superchargers, however, may show more battery degradation than if you use a home charger whenever possible. But even then it usually isn't a "night & day" difference.

if I boil all the 100+ (no exaggeration) pages of battery posts down to one specific opinion to give a "super high level" opinion, its that "ALL home charging is = "Slow charging", especially for a Model 3 which maxes out home charging at 48amps. For the purposes of "slower charging is better" the delineation is "Supercharging = fast, ALL AC charging = slow" with "AC charging" being all Level 2 charging, no matter where it is done (home, L2 destination chargers, etc.
 

KenC

Active Member
Sep 4, 2018
3,704
3,362
Maine
A wall connector is better, except in some cases where people have mentioned that the electricians estimate is double or more when installing a Tesla wall connector over a NEMA 14-50.
 

Rocky_H

Well-Known Member
Feb 19, 2015
6,660
7,951
Boise, ID
Like the USB standards, Tesla changes their charge connector every 10 years or so and other brands change much more often than that. So yeah, your next car might use a different connector and would need an adapter to use with your old wall charger.
That's a really odd thing to say for a company that has only been selling cars for a little over 10 years.
With their original Roadster, yes, it did have its own unique kind of connector, but that was also just for AC charging. It did not do any form of DC fast charging. When they were designing the Model S, they wanted to make a charging port that could detect and dual-purpose on either AC or DC charging formats, so it did need a new connector type with different pins, and they have stuck with that ever since. So it's not like they change it frequently just to change it.
Granted, in Europe, they had the Type 2 and then on newer cars expanded it to CCS2, but that is still mostly the same.

Agree, with one more "Pro" for the Tesla wall connector. Button on Tesla charging cable handle will conveniently open the charging port, whereas the J-1772 non-Tesla brand EVSE does have such a button...
I don't get why people STILL bring this up. It hasn't been relevant since about 2015. On all of the cars since about 2015/2016, they put in the motorized charging port door that is touch to open. So just pretend that the corner of the charge port door is that "button" and push it.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
6,660
7,951
Boise, ID
Okay, well...It's still relevant for me since I have a 2013 S. If it's not relevant for other cars/drivers that are newer, they can disregard.
I get that for you, but you were telling this to new owners in the Model 3 section of the forum. Sorry if I'm coming across as crabby or something on this. It's just not something that is going to be part of the decision tree for Model 3 buyers.
 

freeAgent

Member
Oct 29, 2020
145
127
SoCal
True enough, but I was thinking of another aspect:

With J-1772 EVSE you have to futz with the Tesla adapter. If Tesla is the only car, you have the option of leaving the Tesla adapter on your home EVSE but then you should remember to take it with you on trips. To avoid forgetting, I put the adapter back in the car after each home charging. A less frugal person than me would own two J-1772 adapters but then the price difference really is narrowing.

I personally choose the 14-50 route with a J-1772 EVSE for these reasons:
  • I want visitors to have the option to charge with whatever EV they own
  • I also own a non-Tesla EV
  • I want my EVSE to play nicely in a 'smart' home. For now that means the Grizzl-E EVSE but I imagine other J-1772 manufacturers will adopt open standards in the near future.

I am one of those less frugal people who has a non-Tesla EVSE and a second J1772 adapter. It just lives permanently on the end of my EVSE charging cable so I can keep my other adapter in my car and not worry about forgetting it. I like the ability to charge any EV with my EVSE without having to purchase (or rely on guests purchasing) third-party Tesla-to-J1772 adapters such as the TeslaTap (which is also pricier).
 

Gasaraki

Active Member
Oct 21, 2019
2,010
1,255
Syracuse, NY
If you've already arranged to have a 14-50 installed, the 2nd gen universal mobile connector with the 14-50 plug is the way to go. It's less expensive than the wall connector as well. The only real advantages of the wall connector is that it is weatherproof and can be installed outdoors (not a concern for you) and that it can charge at 40A or 48A, if you electrical panel can support it, and if you're not buying a SR+ (The SR+ onboard charger is limited to 32A anyways).

The 14-50 has long term advantages as well. Your next car will probably be electric, but it might not be a Tesla. The 14-50 allows you to connect another type of charger easily at that point.
The mobile connector is more expensive that the wall connector. $500 for the wall connector vs. $520 for the mobile connector.

 

TheRFMan

Member
Dec 15, 2019
554
422
Ottawa, Canada
The mobile connector is more expensive that the wall connector. $500 for the wall connector vs. $520 for the mobile connector.

Note that I said "universal mobile connector" not "corded mobile connector". The UMC is quite a bit cheater than the Wall Connector.
 
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Silicon Desert

Active Member
Oct 1, 2018
3,598
3,493
Sparks NV / GF 1
First change, change display from mileage to percentage. Mileage is definitely not accurate! Loving the electric lifestyle.
Uh no, both display calculations are based on the same source, just a different way of displaying the information. One is not more accurate than the other. It is a personal choice. Some people like percent and some don't.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
6,660
7,951
Boise, ID
Uh no, both display calculations are based on the same source, just a different way of displaying the information. One is not more accurate than the other. It is a personal choice. Some people like percent and some don't.
While I appreciate your heart on this, they actually are different and are measuring different things. The percent is simply a fullness measurement. It is a ratio of the amount currently in it over how much it currently could hold. The rated miles one is going by the actual amount of energy and then scaling it by a fixed number.

So the way this would show up as some noticeable differences could be this. Let's say when a car is new, it could show 300 rated miles and 100% fullness. After 15 or 20 years, when the battery has degraded and lost some capacity and has less energy that it can hold, the rated miles number would show that, where it would only display 220 or 250 rated miles, because it's going by that smaller amount of energy still scaled by the same fixed constant. But you would never know that with %, as it would still continue to show that it was "full" at 100%.

Also, % means what on a SR Model 3 versus a Model X 75 versus a Model X 100 versus a Plaid Model S versus a standard Cybertruck versus a Tri-motor Cybertruck? At least the rated miles numbers are adjusted by each vehicle's various efficiency levels to the consistent EPA testing methods. So yeah, the "rated mile" is always going to be optimistic versus people's real miles, but at least by similar amounts across all kinds of vehicles.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,330
11,672
Riverside Co. CA
While I appreciate your heart on this, they actually are different and are measuring different things. The percent is simply a fullness measurement. It is a ratio of the amount currently in it over how much it currently could hold. The rated miles one is going by the actual amount of energy and then scaling it by a fixed number.

So the way this would show up as some noticeable differences could be this. Let's say when a car is new, it could show 300 rated miles and 100% fullness. After 15 or 20 years, when the battery has degraded and lost some capacity and has less energy that it can hold, the rated miles number would show that, where it would only display 220 or 250 rated miles, because it's going by that smaller amount of energy still scaled by the same fixed constant. But you would never know that with %, as it would still continue to show that it was "full" at 100%.

Also, % means what on a SR Model 3 versus a Model X 75 versus a Model X 100 versus a Plaid Model S versus a standard Cybertruck versus a Tri-motor Cybertruck? At least the rated miles numbers are adjusted by each vehicle's various efficiency levels to the consistent EPA testing methods. So yeah, the "rated mile" is always going to be optimistic versus people's real miles, but at least by similar amounts across all kinds of vehicles.

Your description is why I use miles instead of percentage. I think some people recommend percentage over miles to try to get people to not focus on the fact the miles never roll off 1:1.

I (overgeneralize) using percentage as "its 100% of what?", for the reason you mentioned. With that being said, if using percent helps someone not focus on "my battery lost another 6 miles this month, and I am down 14 miles since I bought it 12 months ago!!! AAAHHHHHHHHH!!!!!!!!" then that is likely best for them, lol.
 

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