Join The Community

HPWC charging a non-Tesla car

Suppose you have a second EV that is not a Tesla.
Is there a way to use HPWC to charge it ?
Obviously HPWC can feed up to 80A that not all EVs can take, but you can dial it down.
Installing a separate circuit for the second car may not be an option as you can exceed the max rated power for your home service.

If you can convert the Tesla connector to J1772, then you can connect it to another EV that has J1772. Because the signaling for the HPWC is compatible with J1772, you won't have to dial anything down. The other EV will only take the current it needs.

I don't know of anyone who has converted the Tesla HPWC connector to J1772. One way to do it is to cut off the Tesla connector and attach a J1772 connector. Some people have done this for the UMC. The Tesla can charge form the J1772 connector with an adapter. Another way to do it would be to obtain a Model S inlet port and wire it to a J1772 cable.

Last choice is to forgo the HPWC and just use a 80A J1772 EVSE or build your own (

It would be theoretically possible to have a converter (just the inverse of the Tesla J1772 adapter), but AFAIK nobody has done it. A one-off adapter will cost more than another charger and you would have to reverse-engineer the Tesla protocol, so that won't be viable.

Aside from using J1772 to charge both as @AlexK suggests, just get a second charger -- there aren't any J1772 cars on the market that can even make use of 40A that I know of, much less 80A. Sharing one EVSE between two cars means having to move the charge cable every night to keep both cars charged - the inconvenience seems hardly worth saving <$1k (installed, for example an LCS25) for a second charger. | SEPTEMBER 9, 2013: A one-off adapter will cost more than another charger and you would have to reverse-engineer the Tesla protocol, so that won't be viable.

There is no need to reverse engineer the Tesla protocol because it's the same a J1772 - just an adapter to pass the signals through.

There are cars that can take 40A or more, Fiat 500e is one of them.
As far as installing a second charger, that's not an option if your current one is pushing the limits already.
Upgrading your electrical service just to have two of them is definitely more expensive.
I guess someone will come up with a "reverse" connector tesla -> J1772 at some point.
J1772 is way more common on EVs.


I like this option a lot.
If I ever get a non-Tesla, I'll just do that:

thanks !

An 80amp J1772 charger is what I would suggest - and purchase a second J1772 adapter for the Tesla so you keep one on the car and one attached to the home charger.

Most if not all EVs will accepte a J1772 either directly or with an adapter.

Using a Tesla HPWC, with an aftermarket adapter or modification like replacing the connector with a J1772, could cause warranty problems with the Tesla and/or the other EV.

Just because a Tesla car is compatible with a J1772 EVSE does not mean that a Tesla EVSE is compatible with a J1772 car.

I'd be really careful (aka avoid) trying to use an HPWC with a J1772 car other than a Tesla, unless you can get Tesla to say that the HPWC is fully J1772 compliant.

Also be sure to check with an electrician before assuming that your panel cannot support a second EVSE. There are a variety of fully legitimate ways to use physically smaller circuit breakers to add circuits to an apparently full panel.

@joehuber | SEPTEMBER 9, 2013: I'd be really careful (aka avoid) trying to use an HPWC with a J1772 car other than a Tesla, unless you can get Tesla to say that the HPWC is fully J1772 compliant.

It's "well known" in tech circles that the Tesla Model S connector is electrically the same as a J1772 connector. Tesla was involved in the J1772 standard, but they decided to use a different connector. Even the Roadster charger port has been converted to J1772. Check out some of the threads at

Tesla Model S UMC cut open and modified to J1772
Tesla Roadster to Model S converted to J1772

Number of breakers can be overcome, but not the amount of power available. Few residential installations have enough excess capacity to support the addition of two 100amp EV chargers. However, you could share a single 100amp circuit with two EV chargers - just put in a 100amp transfer switch to switch the circuit between them.

Who would want a nonTesla EV?

Sorry, that was uncalled for...

Alex K

Personally I still wouldn't assume complete and ongoing compatibility with J1772 unless Tesla commits to that as a product feature. They may have "Extended" the J1772 protocol or alternatively only implemented a subset of it for purposes of supporting the Model S's needs. That doesn't mean an HPWC will necessarily be compatible with ALL current or future J1772 compatible EVs.

They might even have started from the same technology base originally and still diverged over time. I'm not saying that you're incorrect. Only that I personally wouldn't count on the current and onging compatibility myself.

Tesla made the plug different from J1772 for a reason, and it MIGHT have been for more than just the increased current carrying capacity.


Here is a 70A J1772 charge station that will work for the Model S, Roadster, Leaf, Volt, and pretty much anything else you can think of. It was originally developed for the Roadster.

"Bad request" Drilled my way down to "rebranded" site":

Brian, I don't have any problem viewing the site. I'm not sure I would buy anything from them, however. I'm guessing that the TS70 is just leftover stock. It's a pretty good price, though.

Info page sez Homestead is now hosting its own material. And then a subscription is required.

I dunno Brian. I am able to get most of the way through checkout, and I'm pretty sure I could buy the unit. In fact, the copyright notice on the bottom of the page says copyright 2013 by Clipper Creek, and when I click "About Us," I get info about Clipper Creek. So it looks like Homestead is the company they used to set up an online sales operation. So maybe Clipper Creek does in fact still have TS-70 units to sell -- $1,395.

I'm not sure why your browser can't access the page. Could it be a problem with your Netscape Navigator ca 1996? ;)

Site behaves differently now, got thru directly. Maybe I caught them during an update.

FF 23.0.1

I guess that if the "reverse" J1772 adaptor (from UMC/HPWC to J1772) is still not available... it's because it's not technically possible?

it should be possible, signaling is the same, only the form factor is different.
J1772 to Tesla connector is only plastic adapter without any electronics.

Technically possible but you need to license the design from Tesla. For now, I don't think they are licensing.

Last thing you want is somebody trying the adapter at a supercharger.

I'd rather not see such adapters if non-Tesla could pull up to a supercharger and fill their car up free. (given we paid for the SCs)

The problem isn't with non-Trsla use of Superchargers. It's the fact that J1772 is AC charging, while Supercharging is DC. Nothing would happen if they tried to use such an adapter. Instead, they could hog a Supercharger thinking it was charging and come back without even a charge to show for it.

So, it is worse than getting free charges, it might give some people justification to block Superchargers.

@ir @nhirsch : Good point. Thanks

(posted on another thread)--

Apparently J1772 is evolving to handle DC charging at up to 240kW:

Not formalized yet.

I've just been searching quite a bit, and I cannot find an adapter for a HPWC handle to a J1772. Does it still seem like no one has made one of those? There is a hotel that got a HPWC installed, and they said they're getting the adapters to J1772, but I didn't think they exist, so I'm afraid they are confused and are going to get the wrong thing.

Brian, that is the SAE Combo plug and it is formalized. BMW uses it for the i3. It is a good standard, if bulky an unwieldy compared to the Tesla plug. Another potential adapter needed for the S.

X Deutschland Site Besuchen