Wall Connector for M3 RWD and MYLR

[theocguy]

Hi,

I am planning to have a professional electrician to install a single Tesla Wall Charger for M3RWD and MYLR.

I have read that M3RWD only can charge at 32A with a 40A breaker, and MYLR can charge at 48A with 60A breaker.

Can a 60A breaker be installed and used for both M3RWD and MYLR charging? Or would it be safe to install a 40A breaker only?

However, I understand that for 40A breaker, MYLR can only charge at 29miles per hour range compare with 60A breaker 42miles per hour range.

If i need to optimize on the charge range on both cars, should I get 2 wall-chargers? I am trying to do cost-effective way to charge the cars, but also, want to make sure the MYLR gets charged in time for next day to use.

Any feedbacks/recommendation would be much appreciated.

 

[jjrandorin]

If you are getting a tesla wall connector, its a device that provides power, up to its maximum. The CAR determines how fast it will charge at. This means that you can safely and confidently have a 60amp circuit installed for a tesla wall connector, and the Model Y LR will charge at 48 amps, and the model 3 standard range will charge at 32 amps, from the same wall connector.

If you cant put in a 60amp circuit easily because of needed panel upgrades or something, feel free to put in less, but if you are going to have 2 teslas, and are putting in a wall connector anyway, ask the electrician if your panel can take the 60 amp circuit.

As far as the "one vs two" wall connectors, thats all in how much you want to shuffle the plug between the cars, etc. Do you "need" 2 wall connectors? Probably not, even in CA when you are trying to cram all the charging in during a "midnight to 6 am" window.

Is it more convenient to have 2 wall connectors for 2 cars? It can be more convenient, as each person can simply "plug in" when they get home.

I currently have two teslas (just got my wife a model Y, after having my model 3 since 2018). I was planning on just sharing the already installed gen 2 wall connector I had in the garage, but during the "plan to replace wifes X3" discussions, she said she wanted a Model Y and once we did the numbers and found we could make that happen, said "Oh do I get one of those wall charger thingies on my side of the garage as well, so I dont have to draaaagggggg "yours" over to my car?'

I blinked a couple times and said "sure honey, we can get one put over on that side of the garage too."

I have mine setup in load sharing, so they share the 60amp circuit and load balance between them. This way, I am not using any more power than I was already using / (that permits were pulled for). One car charging = full 48amps for either one of them. If the other one starts charging, it splits the power between the two. When one finishes, the other one then ramps back up to the full 48amps.

Works exactly like you would expect, and is super convenient. "necessary"? Not in the slightest, we could have made due with much less, especially since my wife only drives like 3k miles a year or so on average. Convenient? You bet.

Easy for her to just "plug in" when she gets home, knowing that I have set the car to charge to the level I want to maintain them at, and the car will charge whenever I have it set, so she doesnt have to worry about remembering to unplug my car, plug hers in, etc (the discussion points she mentioned)? Yes, yes it is.

I just want to be sure I am saying " this is not necessary", but its possible, and kinda cool. You can totally share one connection, with no issues other than moving the cable back and forth.

 

[RayK]

Yes, a 60A breaker would be fine to charge the 3 at 32A. The car will limit the current to whatever it's been designed for; it won't try to draw 48A. If your panel can support simultaneous chargers (32A and 48A = 80A), then yes you could do this; consult a qualified electrician to see if a load analysis allows. Whether you really need two chargers is dependent upon how many miles you will drive in a day for both cars. 40+ MPH when charging at 48A means you can get almost 170 miles in less than 4 hours for your Y. 4 hours will get you about 120 miles for the 3. I can understand not wanting to share a single charger between the two vehicles as that implies you would have to switch the cable from one car to the other sometime during the night/early morning.

 

[theocguy]

I have mine setup in load sharing, so they share the 60amp circuit and load balance between them. This way, I am not using any more power than I was already using / (that permits were pulled for). One car charging = full 48amps for either one of them. If the other one starts charging, it splits the power between the two. When one finishes, the other one then ramps back up to the full 48amps.

Works exactly like you would expect, and is super convenient. "necessary"? Not in the slightest, we could have made due with much less, especially since my wife only drives like 3k miles a year or so on average. Convenient? You bet.

Hi @jjrandorin,

thank you very much for taking your time to reply. Your situations of having 2 Teslas with the solution in place on charging is what I would like too. As i thought, it would be "cheaper" to have one wall connector charger but I also know I would have to plug/unplug and switch to different car when one is done. We are using the tier mode from SCE so the time of charge is no different. We will also need to do some deep dive on the TOD usage. At the time SCE asked us to opt-in TOD, our usage was not able to justify to use TOD. In fact, TOD would cause more.

Anyhow, just want to make sure I understand that. You DO have 2 wall connectors but you have them setup in load sharing. So both of them are on the same 60A circuit. Is it right?

Also, which 2 Teslas do you have?

 

[theocguy]

Yes, a 60A breaker would be fine to charge the 3 at 32A. The car will limit the current to whatever it's been designed for; it won't try to draw 48A. If your panel can support simultaneous chargers (32A and 48A = 80A), then yes you could do this; consult a qualified electrician to see if a load analysis allows. Whether you really need two chargers is dependent upon how many miles you will drive in a day for both cars. 40+ MPH when charging at 48A means you can get almost 170 miles in less than 4 hours for your Y. 4 hours will get you about 120 miles for the 3. I can understand not wanting to share a single charger between the two vehicles as that implies you would have to switch the cable from one car to the other sometime during the night/early morning.

hi RayK,

My wife will drive the MYLR and she would drive more miles on that than I would drive on M3 RWD. as I will be working from home for few days a week, I could plug in the connector on my car to top it off.

thanks for your feedback,

 

[jjrandorin]

Anyhow, just want to make sure I understand that. You DO have 2 wall connectors but you have them setup in load sharing. So both of them are on the same 60A circuit. Is it right?

Also, which 2 Teslas do you have?

I mentioned it in my post (but it WAS a wall of text, lol). I have a model 3 performance and my wife now has a model Y performance. Both capable of up to 48amp charging, but as I mentioned, the car is the device which requests power so the car will request what its capable of.

I have 2 Tesla wall connector Generation 2 (Gen 2) versions. This version wall connector communicates with other wall connectors via a communication cable, and the install instructions directly from tesla allow one to have a single breaker feeding a splitter, that then connects to each wall connector.

Here is the install video for load sharing on a tesla gen 2 wall connector:

Load Sharing – Second Generation Wall Connector | Tesla Support

View how to create a load sharing network of second generation Wall Connector.

www.tesla.com

One of the differences between the gen 2 and gen 3 (among others) is that gen 3s get commissioned via wifi (vs gen 2 using a physical dial inside the device to denote power), as well as the gen 2 communicating via communications cable and gen 3 via wifi, for power sharing.

Its my understanding that gen 3 tesla wall connectors want a separate breaker for each wall connector in the setup, but I am certainly no expert on this. The PDF for installing gen 3 seems to imply they want a separate breaker for each wall connector, but that after commissioning they will share power.

Wall Connector Power Sharing | Tesla Support

With Power Sharing, you can allow up to six 3 Wall Connectors to share power and charge multiple vehicles at once. Learn how to set up and troubleshoot Power Sharing.

www.tesla.com

https://www.tesla.com/sites/default/files/support/charging/Gen3_WallConnector_Installation_Manual.pdf

Someone more familiar with gen 3s setup would need to chime in on this. I do know that a gen 2 cant intelligently share power with a gen 3, however. I already had a gen 2, so sourced another one.

 

[3sr+buyer]

I have read that M3RWD only can charge at 32A with a 40A breaker, and MYLR can charge at 48A with 60A breaker.

Can a 60A breaker be installed and used for both M3RWD and MYLR charging? Or would it be safe to install a 40A breaker only?

If you install a wall connector on a 60A circuit for 48A charging, the Model 3 RWD will be fine with it. Any EV and EVSE will allow charging at the lower of what either the EV or EVSE say it will do. So a Model 3 RWD capable of 32A charging connected to a wall connector capable of 48A charging will charge at 32A.

Similarly, if you install a wall connector on a 40A circuit for 32A charging, the Model Y LR will charge at 32A when plugged into it.

If you are installing new and committed to using a wall connector, and your main panel can handle a new 60A circuit, there is not much reason to install less than a 60A circuit. The wiring may be a little more expensive, but probably not a lot given the overall cost of the project. (The calculation may differ if you are reusing an existing 40A or 50A circuit.)

 

[EVFamilyGrins]

hi RayK,

My wife will drive the MYLR and she would drive more miles on that than I would drive on M3 RWD. as I will be working from home for few days a week, I could plug in the connector on my car to top it off.

thanks for your feedback,

For your use case, 1 HPWC should be fine. Even if your wife has a very heavy usage, you have time to charge on the work from home days. Try it and if you find it is not working or your usage changes, you can always install a second charger. Discuss the option of expansion with your electrician and maybe add a junction box now just in case you want a second charger in future.

We have a 2018 M3LR and MS and share a HPWC on a 60A circuit. We have never had an issue sharing in 3 1/2 yrs. We basically charge on alternate days. On the few occasions where we both needed to charge on same night, there was plenty of time for 1 car to charge and then switch before going to bed. We had enough space between the two garage bays to install the charger, so it's very convenient to either car.

Other thoughts to consider:
1) Use the UMC to charge from outlet on those days where you both need to charge. Adding 40-50 miles a night to the M3 can make a difference some days while the MY is using the HPWC.
2) Does your wife have Superchargers on her route? Having option to easily stop at an SC for a quick 10 min boost can alleviate range anxiety.

 

[theocguy]

For your use case, 1 HPWC should be fine. Even if your wife has a very heavy usage, you have time to charge on the work from home days. Try it and if you find it is not working or your usage changes, you can always install a second charger. Discuss the option of expansion with your electrician and maybe add a junction box now just in case you want a second charger in future.

We have a 2018 M3LR and MS and share a HPWC on a 60A circuit. We have never had an issue sharing in 3 1/2 yrs. We basically charge on alternate days. On the few occasions where we both needed to charge on same night, there was plenty of time for 1 car to charge and then switch before going to bed. We had enough space between the two garage bays to install the charger, so it's very convenient to either car.

Other thoughts to consider:
1) Use the UMC to charge from outlet on those days where you both need to charge. Adding 40-50 miles a night to the M3 can make a difference some days while the MY is using the HPWC.
2) Does your wife have Superchargers on her route? Having option to easily stop at an SC for a quick 10 min boost can alleviate range anxiety.

great suggestion and I will definitely consider your recommendations. to get 1 charger now and add a 2nd one later seems a good way to go (and do not need to spend $$ on 2 chargers upfront). both of us are doing the local drive, and we have few SCs around if we have to add some charges in the event we have to make it out when range is low.

I will also ask questions to the electrician on the options for future expansion easily.

 

[davewill]

It's exactly the same situation as public charging stations that are usually 30a, but have Priuses that can only charge at 10a, and older LEAFs that can only charge at 16a plug in all the time. As long as the EVSE is properly configured, it will work fine.