Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

What's the Max for the Wall Connector?

This site may earn commission on affiliate links.
Hello, all! First post, so go easy on me.
:)
I just got my M3 LR AWD and a Wall Connector, so I'm new to all of this. I have an electrician coming out to install the charger and he asked how many amps circuit I want installed. From reading the instructions, it looks like 60 amps is recommended, but wanted to ask if there are any benefits to using 60 amps, or if I would see any benefits if I went higher, say 80 or 100? I thought I better ask you all before I had it installed since I'm not sure what the best (fastest?) option would be.

Thank you!
 
Depends. If you live in an area that has a short TOU, then a 100 amp circuit will allow you to charge during the lowest priced electric rate. If you don't then there's not much advantage as even at a 32 amp charge rate, the charge will always be completed overnight. Note that a lower rate of charge heats the battery less. Good in summer, not so good in winter. Below 32 amps the charging becomes inefficient.
 
Hello, all! First post, so go easy on me.
:)
I just got my M3 LR AWD and a Wall Connector, so I'm new to all of this. I have an electrician coming out to install the charger and he asked how many amps circuit I want installed. From reading the instructions, it looks like 60 amps is recommended, but wanted to ask if there are any benefits to using 60 amps, or if I would see any benefits if I went higher, say 80 or 100? I thought I better ask you all before I had it installed since I'm not sure what the best (fastest?) option would be.

Thank you!

Only reason to go over 60 amps is if you plan to have a second HPWC for another Tesla at some point in the future, or have a different model Tesla that with a higher charge rate than the 3. Multiple HPWC can share a circuit and communicate with each other to load share. Model 3 max charge rate is 48 amps for LR battery, so unless you plan to load share or charge a different model Tesla that accepts higher amperage, you won't see any benefit from going higher than 60 amps.
 
Last edited:
  • Like
Reactions: MorrisonHiker
To answer your question, in the purest sense, what you set the charger for when installing it has nothing to do with what car(s) you have. You set the charger for the maximum that your home can safely deliver, based upon the panel and current demands by the rest of the circuits. Then, you set your car to draw what amperage you want, limited to the lower of 1) the car's max draw and 2) what the charger can deliver.

As others have pointed out, putting your charger on a 100 amp circuit enables you to charge an older Tesla that can draw 80 amps or, if you one day own two Teslas (or have a friend, relative, or passer by charging also), you can take advantage of the load sharing ability to deliver up to 40 amps to each car. (This load sharing actually works with up to four wall chargers on a single circuit.)

In short, if your panel and current loads support it, there's no reason not to install your charger on a 100 amp circuit. Doing so future proofs the installation, all for the relatively low cost of some additional copper.*

*If your panel is 400' from your garage or some other atypical installation, obviously the difference in wiring could be significant.
 
Depends. If you live in an area that has a short TOU, then a 100 amp circuit will allow you to charge during the lowest priced electric rate. If you don't then there's not much advantage as even at a 32 amp charge rate, the charge will always be completed overnight. Note that a lower rate of charge heats the battery less. Good in summer, not so good in winter. Below 32 amps the charging becomes inefficient.
I'm sorry, but I'm going to have to call BS on most of this statement.

Charging is NEVER 100% efficient. Charging below 32A is still efficient and is used by many people.
A 100A service isn't going to buy you anything. The carsc charger won't go that fast. FYI the charger is in the car, the cable is just an extension cord.
And even at 32A, you should be able to fit in the TOU low period for a Full charge
 
  • Like
Reactions: woodguyatl
I'm sorry, but I'm going to have to call BS on most of this statement.

Charging is NEVER 100% efficient. Charging below 32A is still efficient and is used by many people.
A 100A service isn't going to buy you anything. The carsc charger won't go that fast. FYI the charger is in the car, the cable is just an extension cord.
And even at 32A, you should be able to fit in the TOU low period for a Full charge
I never said it was 100% efficient, however, there have been a number of folks on TMC who have monitored it and charging at a low amp rate, such as 16 amp, has more losses than at 32 amps or more.

For the M3 100 amps won't buy you anything, but if you want to have your connection listed on PlugShare, 100 amps will allow an S or X to charge at a faster rate.
 
In short, if your panel and current loads support it, there's no reason not to install your charger on a 100 amp circuit. Doing so future proofs the installation, all for the relatively low cost of some additional copper.*

*If your panel is 400' from your garage or some other atypical installation, obviously the difference in wiring could be significant.

There is some wisdom in his reply. However, you will find that AWG 3 is roughly twice the cost of AWG 6. This, in and of itself is probably not monetarily insurmountable, but the effort to pull AWG 3 from the panel to the wall connector is more than twice as tough.
 
  • Like
Reactions: Rocky_H
There is some wisdom in his reply. However, you will find that AWG 3 is roughly twice the cost of AWG 6. This, in and of itself is probably not monetarily insurmountable, but the effort to pull AWG 3 from the panel to the wall connector is more than twice as tough.

I definitely agree with this point. I installed dual wall chargers using the rear entry to the devices, which required a 90-degree bend on the AWG 3. Not fun.
 
60 is all one LR 3 will take(its actually 48 once the wiring and circuit breaker are derated for continuous use). Unless you plan on dual chargers or an S in the future, stick with 60.

BTW, unless you drive a LOT every day, you can probably get by just fine on 30/24 amps... maybe a bit more because you might see charging in very cold temperatures.
 
  • Informative
Reactions: eprosenx
To answer your question, in the purest sense, what you set the charger for when installing it has nothing to do with what car(s) you have. You set the charger for the maximum that your home can safely deliver, based upon the panel and current demands by the rest of the circuits. Then, you set your car to draw what amperage you want, limited to the lower of 1) the car's max draw and 2) what the charger can deliver.

As others have pointed out, putting your charger on a 100 amp circuit enables you to charge an older Tesla that can draw 80 amps or, if you one day own two Teslas (or have a friend, relative, or passer by charging also), you can take advantage of the load sharing ability to deliver up to 40 amps to each car. (This load sharing actually works with up to four wall chargers on a single circuit.)

In short, if your panel and current loads support it, there's no reason not to install your charger on a 100 amp circuit. Doing so future proofs the installation, all for the relatively low cost of some additional copper.*

*If your panel is 400' from your garage or some other atypical installation, obviously the difference in wiring could be significant.
To be pedantic, if you’re using a hard-wired wall connector there’s generally no reason to set the amperage in the car.
 
If you are paying for the labor and your panel has the capacity to do 100 amps, you probably should consider doing 100 amps. Paying a dollar or so a foot for the lower gauge wire and 10 bucks extra for the 60 vs 100 amp breaker is minimal cost comparing to having to have it redone in the future.
 
Only reason to go over 60 amps is if you plan to have a second HPWC for another Tesla at some point in the future, or have a different model Tesla that with a higher charge rate than the 3. Multiple HPWC can share a circuit and communicate with each other to load share. Model 3 max charge rate is 48 amps for LR battery, so unless you plan to load share or charge a different model Tesla that accepts higher amperage, you won't see any benefit from going higher than 60 amps.
Along the lines of @destructure00, I signed Tesla contract to install $250 "pre-wire" up charge to get 100A in the house even though I have less than 100A available on my panel. This pre-wire supposedly get #3 100A wire and space in the conduit for the communication cable to a 2nd Wall Connector to share load.

@mike123abc has the right thinking.
 
Last edited:
To be pedantic, if you’re using a hard-wired wall connector there’s generally no reason to set the amperage in the car.

There are a number of reasons one might want to set a lower than max amperage in the car. For me, personally:
  • My Model S can charge at 80 amps, but I see no reason to stress the onboard chargers that way, so I typically charge at less than 80 amps, unless I need a fast turnaround.
  • In the summer time, when everyone around me is running their home ACs at max, I delay charging until 1 or 2 am and lower the amperage so that I'm being a little kinder to the grid, especially to the transformer serving our cluster of homes.
  • When I want to charge to 100% for some reason, I'll reduce the amperage so that the car reaches 100% right before my planned departure time, rather than sit at 100% longer than necessary.