HPWC charging a non-Tesla car

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.

Alex K | September 9, 2013

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 (

jat | September 9, 2013

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.

Alex K | September 9, 2013 | 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.

sergiyz | September 9, 2013

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.

sergiyz | September 9, 2013


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

thanks !

tes-s | September 9, 2013

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.

SUN 2 DRV | September 9, 2013

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.

Alex K | September 9, 2013

@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

tes-s | September 9, 2013

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.

drp | September 9, 2013

Who would want a nonTesla EV?

drp | September 9, 2013

Sorry, that was uncalled for...

SUN 2 DRV | September 9, 2013

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.

Brian H | September 11, 2013


DouglasR | September 11, 2013

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.

Brian H | September 11, 2013

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

DouglasR | September 11, 2013

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.

Brian H | September 12, 2013

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

DouglasR | September 12, 2013

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? ;)

Brian H | September 14, 2013

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

FF 23.0.1

_thierrY | May 16, 2014

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?

Jolinar | May 16, 2014

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.

ir | May 17, 2014

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.

nhirsch | May 17, 2014

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)

ir | May 17, 2014

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.

_thierrY | May 20, 2014

@ir @nhirsch : Good point. Thanks

Brian H | August 8, 2014

(posted on another thread)--

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

Not formalized yet.

Rocky_H | August 21, 2014

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.

PaceyWhitter | August 21, 2014

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.

hpjtv | November 17, 2014

Anything new on this topic? It would be nice to charge non-Tesla vehicles with the HPWC. Anyone make a J1772 adapter yet?

shop | November 29, 2014

I would have installed an 80 amp HPWC at my public barn, but I didn't since the majority of people charging here need a J1772. The best of all worlds would be an HPWC so the occasional Tesla's could have a fast charge, with a Tesla connector to J1772 plug so everyone else could charge as well.

In theory, it isn't hard to make. You'd have to make or buy a Tesla connector inlet port. I don't think these are actually available anywhere, so you'd have to make your own. Then wire that to a J1772 handle and you're done.

bonaire | November 29, 2014

Clipper Creek CS-100. 19.2 Kw J-1772. They have other units with less KW ratings too.

PatT | November 29, 2014

Yeah but the HPWC has the most power for the price.

hpjtv | November 29, 2014

@PatT true but it can only charge Tesla's and nothing else until there's an adapter.

garygid | April 20, 2015

It looks like Tony Williams is going to make a HPWC-to-J1772 adapter,
and have it available for sale in roughly Q3 2015.

stevenmaifert | April 20, 2015

I think I would leave the HPWC as is and do a $199 service conversion of the UMC:

An HPWC-to-J1772 adapter that can handle 20kW is not going to be inexpensive.

ticobird | April 20, 2015

If you need to charge two vehicles at the same time my solution wouldn't work very well. Anyway, when I had my HPWC installed, I also had the electrician install a NEMA 14-50 on the off chance the electronics in the HPWC misbehaved sometime in the future. This would only be legally possible if the circuit to the HPWC was wired as a 50 amp circuit rather than a 100 amp circuit for a Tesla with two onboard chargers. While this is the reason I chose not to buy the second charger I also saved on not installing two circuits but rather only one which was another reason. I figured I could always add a 100 amp circuit in the future if I actually need one. I've attempted to attached a picture of what I've just described to eliminate any confusion - just remember there is only one 50 amp circuit that runs to both the HPWC and the NEMA 14-50.

AmpedRealtor | April 20, 2015

@ stevenmaifert,

A HPWC-to-J1772 adapter doesn't need to handle 20 kW. I don't think any other EV charges at over 6.6 kW using AC power.

stevenmaifert | April 21, 2015

@AmpedRealtor - The Toyota RAV4 EV has a Tesla 10kW on-board charger. But more to the point, and I'm no expert, but in the electrical world it's been my experience that breakers and other electrical devices/accessories are designed to safely carry the maximum power available, even though they seldom run at max. I don't know if that's a universal code or just good practice. If you click on that link I provided above, you will see that Quickchargepower fits the converted UMC with a 50A J1772 plug. That's consistent with a UMC plugged into the standard residential 240V 50A NEMA 14-50 circuit.

garygid | April 21, 2015

How much does the Tesla charge port socket for the Model S cost
from a Tesla Service Center?

Brian H | April 23, 2015

In NA, breakers are rated for max brief spikes, but only for 80% of that continuous. EU standards limit the breakers to continuous, with no headroom for spikes. The 80% "rule" is an unnecessary limitation there.

jordanrichard | April 23, 2015

garygid, your car should have come with all the adapters you need. If you want additional ones, go to Tesla's accessories page and order which ever one you need. I believe the prices vary based on the type of adapter.

jjenkins | October 12, 2015

Just so I have said it. The 80% derating rule has nothing to do with spikes. It has to do with the capacity of the connection to the breaker. Please consult a licensed electrician prior to adjusting your electrical service. The media loves to point fingers at electric cars when there is a fire when in fact it was the homeowner that caused the issue, let alone you could get hurt.