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

Tesla + J1772 sharing same circuit?

mdgreen

New Member
Sep 7, 2021
1
0
Baltimore
Hi, and apologies if this question has been asked.

I have a M3 Long Range that I charge using a Tesla Wall Connector on a 60-amp (breaker) 240V circuit. My wife recently bought a BMW plug-in hybrid (off topic: I wanted her to buy a Model Y, for her reasons see “PS” below) and so I want to install a second charger.

I’m told that two Tesla Wall Connectors can be connected to a single 60A circuit and networked together so that the two cars charging at the same time will never exceed the maximum current draw — but otherwise both cars can use whatever amperage is available, without limiting charge rate when only one car is charging. This is appealing to me because adding additional amps might require an expensive upgrade to my home electricity service. I also don’t want to permanently reduce the charge rate of my M3 (except obviously on those occasions when we are both charging at the same time.)

My question is: if I install a second Wall Connector and buy a Tesla->J1772 adapter for her car, will the shared current limits still work properly? Or does this only work when two Teslas are plugged in? Alternatively is there a cheaper/simpler option that wouldn’t require any circuit upgrades to that 60A circuit, yet would still allow me to charge my M3 at full rate when she’s not charging? (I know the Tesla connector is a luxury compared to third party units but I’m also hoping we can replace the BMW someday, so I’m willing to spend the money on hope.)

PS To explain the “why” above: I convinced my wife to test drive the Model Y, and at first it was promising: she said it was the most comfortable car she ever sat in. Then she tried driving it and hated the one-pedal regenerative breaking — to the point where she couldn’t even finish the test drive. I told her no problem, you can reduce the aggressiveness of the regen with a setting. However, the lower regen setting has been removed on all newer Teslas! The result is that the MY was out and she insisted on buying this stupid BMW hybrid with its negligible electric range. I’m annoyed that Tesla removed the simple option. It certainly cost them this sale.
 

jmaddr

Active Member
Mar 29, 2019
1,016
1,033
Florida
Interesting antidote about losing a sale. While I think with time even she would likely move to one pedal driving, it does put off first time buyers.

As for your question, no, it won’t work. The J1772 adapter is J1772->Tesla direction only and not the other way around. The male-female adapters just won’t agree.

The only thing I could think of would be to put in a transfer switch which will mean you can’t charge both vehicles at the same time. You will have to down rate to the slower device so-as not to pull too many amps on the lower rated device. Something like this (please have an electrician look at this as it will likely require permits):

 

Sophias_dad

Supporting Member
Supporting Member
Jul 29, 2018
1,532
1,612
Massachusetts
Have you considered trading in your wife for one who makes any effort to learn new things;)? Or just any plain ICE vehicle, given the relative crappiness of the BMW's plug-in hybrid-ness. I imagine your wife would be fine with any BMW.

The onboard charger of a BMW x5 tops out at 3.7kw, so even if the sharing doesn't work at all you could allot the BMW charger 15 amps of your 48 continuous and you'd still be fine with ~33 amp charging. Or for even more fun don't even get a real charger for it, just a fake plug going to a box on the wall that she can feel happy plugging in every evening.
 

Sophias_dad

Supporting Member
Supporting Member
Jul 29, 2018
1,532
1,612
Massachusetts
Interesting antidote about losing a sale. While I think with time even she would likely move to one pedal driving, it does put off first time buyers.

As for your question, no, it won’t work. The J1772 adapter is J1772->Tesla direction only and not the other way around. The male-female adapters just won’t agree.

The only thing I could think of would be to put in a transfer switch which will mean you can’t charge both vehicles at the same time. You will have to down rate to the slower device so-as not to pull too many amps on the lower rated device. Something like this (and I’m not recommending this as I have no experience with it…also, please have an electrician look at this as it will likely require permits):
OP is referring to this, or something like it...

 

Rocky_H

Well-Known Member
Feb 19, 2015
6,765
8,354
Boise, ID
My question is: if I install a second Wall Connector and buy a Tesla->J1772 adapter for her car, will the shared current limits still work properly?
I think that is correct, using an adapter like @Sophias_dad mentioned. There are a couple of others like it that do that same thing.

Then she tried driving it and hated the one-pedal regenerative breaking — to the point where she couldn’t even finish the test drive. I told her no problem, you can reduce the aggressiveness of the regen with a setting. However, the lower regen setting has been removed on all newer Teslas! The result is that the MY was out and she insisted on buying this stupid BMW hybrid with its negligible electric range. I’m annoyed that Tesla removed the simple option. It certainly cost them this sale.
Damn it, Tesla! I'm pretty angry that Tesla removed that option. I was just having this discussion in another thread about how frustrating it is that they did this. Aside from the winter driving conditions, this very example you gave is kind of a big deal. When I took my test drive, back in 2013, I did the same thing--I popped my foot off the accelerator and was thrown forward and was shocked and irritated. I asked the Tesla guy to turn it down to Low, and did the rest of my test drive and enjoyed it. Once you are aware of it, and are retraining to gradually pull your foot back, yes, I turned regen back on full once we actually got our car and was fine and like it that way now. But yes, I think they probably are losing sales from that.
 
  • Like
Reactions: jjrandorin

Timbo2

Member
Jun 8, 2019
215
169
USA
Damn it, Tesla! I'm pretty angry that Tesla removed that option. I was just having this discussion in another thread about how frustrating it is that they did this.

Unsubstantiated rumor is that during "discussions" with the EPA during range ratings they didn't want them based on something they felt many users were going to disable. Tesla elected to remove it to be able to post higher EPA mileage numbers.

Personally coming from decades of driving a manual transmission I love the regen. However, on icy roads and snow I'm also very happy to be able to disable it. I also occasionally disable regen and do some "spirited" braking to help exercise the brake calipers and put some wear on the pads and rotors to keep things moving and clean.
 

F14Scott

Member
Apr 7, 2019
209
381
Houston
I have two Tesla 2nd Gen HPWCs that share a single 60A breaker and are connected via the communication cable. They are each manually restricted to 48 Amps via the internal physical dial. One charges my wife's TM3 AWD. The other is for my J1772 MINI SE.

Alone, the TM3 draws up to 48 Amps.
Alone, the MINI draws up to 32 Amps (the car's limit).
When both are charging simultaneously, each can draw up to a max of 24 Amps.

In other words, my setup does exactly what you propose. However, comma,

I believe the Gen 3 Wall Connectors require one breaker per connector. Once done, however, they can be software configured to draw and share per the user's desires, via WiFi.
 
  • Informative
Reactions: mrau

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,750
12,445
Riverside Co. CA
The onboard charger of a BMW x5 tops out at 3.7kw, so even if the sharing doesn't work at all you could allot the BMW charger 15 amps of your 48 continuous and you'd still be fine with ~33 amp charging. Or for even more fun don't even get a real charger for it, just a fake plug going to a box on the wall that she can feel happy plugging in every evening.

I havent driven the new X5 Hybrids, but the old ones absolutely needed to be charged because they felt underpowered unless you had both motors available. We checked them out when we leased my wifes X5 I have talked about on a few threads (2015-2018). We ended up with a X5D on a lease, which wasnt bad but certainly not something I was ever going to keep.

@Rocky_H , I realize this isnt the "wtf were they thinking on removing a regen option", but I certainly agree with you on this 1000%. My wife drives my car very infrequently, and her profile is set to low regen because she has never really gotten used to it. She would if she drove the car every day. She knows how to drive a manual transmission vehicle, but its probably been 25 years since she has driven one. I am sure she could get used to it "eventually" but she doesnt drive my car more more than 4-5 times a year, if that.

@Timbo2 , very interesting, and I could totally see that as a reason. Thanks for sharing the rumor.
 

Gasaraki

Active Member
Oct 21, 2019
2,079
1,440
Syracuse, NY
Interesting antidote about losing a sale. While I think with time even she would likely move to one pedal driving, it does put off first time buyers.

As for your question, no, it won’t work. The J1772 adapter is J1772->Tesla direction only and not the other way around. The male-female adapters just won’t agree.

The only thing I could think of would be to put in a transfer switch which will mean you can’t charge both vehicles at the same time. You will have to down rate to the slower device so-as not to pull too many amps on the lower rated device. Something like this (please have an electrician look at this as it will likely require permits):

It WILL work.

I think the wall connector knows what draw it is currently providing and tell the other wall connector to split the power when needed.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,750
12,445
Riverside Co. CA
Wifey decided to turn down a model Y for ANY BMW suv. She probably doesn't care about power very much.


Yes, was thinking that was the reason. (Turning regen to low reduces 'fuel' economy', in case anyone doesn't want to go back and find it)

I understand completely the point you are making, but think that quite a bit of time driving a tesla has skewed your feeling of what "fast" is, lol. The thing is, its "Teslas are extremely fast", not necessarily that everything else is super slow. Many people drive a tesla and think "WTF why would anyone EVER need to go that fast?"

My wifes current lease (that ends Jan 10 2022), is an X3 M40 which is, for an ICE vehicle pretty darn quick. Of course, a tesla makes it feel slow, but its not really a slow vehicle.

I dont think its quite "fair" to say that someone buying "any" BMW suv doesnt care about power... they have several that are M vehicles that are performance oriented, that feel and sound great for SUVs. I have driven X5Ms (at BMWs performance center in southern california on a "driving class" day) and X3Ms (test drives).

They are faster than most people would ever need out of an SUV... but yes slower than teslas unless you compare a SR model Y with the M versions of those vehicles.
 

Sophias_dad

Supporting Member
Supporting Member
Jul 29, 2018
1,532
1,612
Massachusetts
For some reason I'm reminded of someone I had the misfortune of riding with, as a passenger in his ICE suv(Acura, I think, probably 10 years ago). He had two throttle settings, too much and none. There was no "hold the pedal to a good spot where the engine output matches drag", just "oh, I'm at the speed I want, foot off gas" followed by "oh, I'm 5mph under the speed I want, put in 25% throttle(or whatever)", maybe 20-30 seconds later.

I never rode with him again. I can't imagine what fun full regen would be with him as the driver, it was bad enough when the ICE would coast. I gotta assume a Tesla with him at the wheel would feel like a rodeo event.
 
  • Funny
Reactions: Rocky_H

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top