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Tesla + J1772 sharing same circuit?

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.
 
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jmaddr

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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

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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

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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

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Feb 19, 2015
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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.
 

Timbo2

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Jun 8, 2019
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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.
 
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.
 
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jjrandorin

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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.
 
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.
 

Sophias_dad

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because they felt underpowered
Wifey decided to turn down a model Y for ANY BMW suv. She probably doesn't care about power very much.

I could totally see that as a reason.
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)
 

jjrandorin

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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

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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.
 
Hi all — wanted to post an update.

Found out that the Gen3 wall connector is not compatible with the Gen2 I already owned, and this shot my plans (worse, they stopped selling Gen2s). However Tesla just released a new connector that has a native J1772 and it appears to be a Gen2! So this seems perfect!

However the Tesla Shop web page for the product says it can only be connected to other “Gen2 J1772 connectors” rather than any Gen2 connector. Do you think that’s accurate, or just a mistake?
 

Sophias_dad

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Hi all — wanted to post an update.

Found out that the Gen3 wall connector is not compatible with the Gen2 I already owned, and this shot my plans (worse, they stopped selling Gen2s). However Tesla just released a new connector that has a native J1772 and it appears to be a Gen2! So this seems perfect!

However the Tesla Shop web page for the product says it can only be connected to other “Gen2 J1772 connectors” rather than any Gen2 connector. Do you think that’s accurate, or just a mistake?
I'd wager it is not accurate and not a mistake(!).

Its most likely trying to make it clear that you can't do power sharing with a non-tesla J1772 charger(aka juicebox, chargepoint, so on), even though to most people that's probably obvious. I'd wager the innards are almost exactly the same as a Gen2 HPWC, aside from perhaps some cheaper relays(contactors) for 40 amps instead of 80 amps.
 
Hi all — wanted to post an update.

Found out that the Gen3 wall connector is not compatible with the Gen2 I already owned, and this shot my plans (worse, they stopped selling Gen2s). However Tesla just released a new connector that has a native J1772 and it appears to be a Gen2! So this seems perfect!

However the Tesla Shop web page for the product says it can only be connected to other “Gen2 J1772 connectors” rather than any Gen2 connector. Do you think that’s accurate, or just a mistake?
Looks like it might work with your current Gen2 and should work for sure if you get two of the j1772 gen2s.

"Note: Tesla recommends installing with a 50-amp circuit breaker for maximum power output. For owners with multiple electric vehicles, up to four Gen 2 J1772 Wall Connectors can share available power, making it possible to charge multiple vehicles at home. Power sharing is only possible when connected to other Tesla Gen 2 J1772 Wall Connectors."

 

Rocky_H

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Feb 19, 2015
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However the Tesla Shop web page for the product says it can only be connected to other “Gen2 J1772 connectors” rather than any Gen2 connector. Do you think that’s accurate, or just a mistake?
I'd wager it is not accurate and not a mistake(!).
I would concur with that. There is a reason, but I think it's a different reason than @Sophias_dad thinks.
I'd wager the innards are almost exactly the same as a Gen2 HPWC, aside from perhaps some cheaper relays(contactors) for 40 amps instead of 80 amps.
I would be about 75% confident that the innards are exactly the same as the regular wall connectors.
The J1772 plug/cord they are using is probably just thin and not capable of supporting 80A current. So they put the warnings to never use it on more than a 50A circuit.

So then THAT would dictate why they are saying not to share with other standard wall connectors. Those could be on a 100A circuit, and there is no method to set one to be different than that. So if you shared this J1772 version with that, it would also be set for a 100A circuit and would melt the cord if a car connected and tried to draw 80A. So they warn to only share with others of this same type to keep that 50A circuit restriction.

So really, I would bet this will work fine sharing with other Gen2 wall connectors, as long as you are using a 50A circuit or less.
 
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miimura

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Aug 21, 2013
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Looks like it might work with your current Gen2 and should work for sure if you get two of the j1772 gen2s.

"Note: Tesla recommends installing with a 50-amp circuit breaker for maximum power output. For owners with multiple electric vehicles, up to four Gen 2 J1772 Wall Connectors can share available power, making it possible to charge multiple vehicles at home. Power sharing is only possible when connected to other Tesla Gen 2 J1772 Wall Connectors."

That language says to me that the J1772 Wall Connector won't work in tandem with a standard Gen 2 Tesla Wall Connector. In the best case, you will have to turn down the Tesla Wall Connector from 60A (48A to the car) to 50A (40A to the car) to match the J1772 Wall Connector. Gen 2 Power sharing must all be the same current capability. Gen 3 can mix and match different circuit sizes and load share a different total amperage.

Tesla should really make a J1772 Gen 3 Wall Connector. I think these Gen 2 units are leftover production from the Destination Charger program. That program is pushing toward allowing billing for usage, which requires connectivity provided by the Gen 3 units.
 
Hi all — wanted to post an update.

Found out that the Gen3 wall connector is not compatible with the Gen2 I already owned, and this shot my plans (worse, they stopped selling Gen2s). However Tesla just released a new connector that has a native J1772 and it appears to be a Gen2! So this seems perfect!

However the Tesla Shop web page for the product says it can only be connected to other “Gen2 J1772 connectors” rather than any Gen2 connector. Do you think that’s accurate, or just a mistake?
I posted about this in another thread but I actually made a video a few weeks ago with a J1772 Wall Connector that I got off eBay (before they were publicly sold) and tested load sharing with a HPWC. You get an error message that is straight from the user manual regardless of which setting the rotary dial is on (40A, 80A, etc):
1636060171157.png


Official Tesla J1772 Wall Connector - Unboxing and Review
(Load sharing part starts @4:55)

I was, however, able to get it to successfully load share with a Tesla 14-50 Wall Connector, as it has a 40A max output as well!
I'd wager the innards are almost exactly the same as a Gen2 HPWC, aside from perhaps some cheaper relays(contactors) for 40 amps instead of 80 amps.
You are absolutely correct, though from what I saw when tearing it down, it was pretty much just the thickness of the wiring was dialed down.
 
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