Your J1772 cable probably doesn't have any extra wires available to put the extra power supply inside the EVSE enclosure. Tony could sell you a complete 40A cable with a Tesla connector spliced on that has the extra wires. Then you could connect that cable to your EVSE and leave your J1772 cable untouched and available for future use. You should call Quick Charge Power and see what solutions they have available for your situation. They may also have some cables available from their JWall conversions.
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Tesla Model S UMC cut open and modified to J1772
- Thread starter TonyWilliams
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Mishakim
Member
Good point about the cable possibly missing the conductor I need. I haven't been able to find clear schematics for it, and haven't yet taken the simple step of taking the cover off to see what's there. Getting a whole cable & plug assembly is probably the way to go, though the cost of the cable may tip me towards just buying a HWPC and selling the EVLink.
MacGreiner
5YJ
Mishakim
Member
That's what I figured. They either didn't have that or I overlooked it previously. At that price, I would only need to get $200 for the old EVSE to beak even on a new HPWC. They have the plug alone for only $70, which makes it worth the effort.
Thanks for the hard work. I came across an older Wall Connector in bad shape with a thin white wire in the cable. For the life of me, I cannot figure out what the white wire does other than assume it is a neutral that isn't used any more. Did you come across a white wire in your research?
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I was thinking about this the other day b/c of a different thread. We know that when the UMC is using 240 V its basically using pushing 120 V to each "hot" line out of phase with the other for a combined 240 V between the two "hot' wires.
How then is the circuit completed when the UMC is using the NEMA 5 prong with a hot and a neutral? Are the internal wires of the UMC still terminating to the two "hots" with one acting as a neutral" in this case?
davewill
Active Member
Yes. In fact it's perfectly possible to wire an adapter from one of the 30a 240v plug adapters to a 30a 120v outlet. But it's important to get the neutral on the right "hot".
Where do you find the bare cable that matches the UMC --> Tesla plug part? I need to extend this. It would be easy to use 6/2 AWG SOOW to hack something together, but I really want the result to be clean, sealed, and viable for outdoor.
Although I'm probably overthinking it, because i don't think a hurricane could penetrate the UMC, based on the teardown in this thread...
Although I'm probably overthinking it, because i don't think a hurricane could penetrate the UMC, based on the teardown in this thread...
There are more wires in there. You can buy the special cable or you can just have them extend it.
J1772 Cable
Tesla UMC extension
thanks, I didnt realize he would sell the cable directly without the service (I really want to do it myself, for peace of mind).
Anyone have ideas about joining the heavy cables? with 12AWG I would strongly consider using several crimp connects, but a little heat shrink isn't going to do it for strain relief/weatherproofing the joint.. Need something better, but never had to do this kind of application before.
Anyone have ideas about joining the heavy cables? with 12AWG I would strongly consider using several crimp connects, but a little heat shrink isn't going to do it for strain relief/weatherproofing the joint.. Need something better, but never had to do this kind of application before.
If you haven't done it before and are looking for ideas for how to do it right, why are you opposed to paying them to do it? They've clearly thought about the right way to do it.
I don't recommend splicing an EV cable. But if you have to, here's something that might help you.
https://www.amazon.com/gp/product/B005GDFRJA/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
mchevrier
Member
Has anyone done this with the v2 UMC?
I found one for $40 on eBay with a cable cut and would like to put a J1772 connector on it if it's not dead.
For the larger wires, it's pretty clear that the green is ground, I'd guess that blue is neutral or brown is hot.
As far as the low voltage lines go, my guess is that the white/orange in a pair are for the 3.3V source and that blue and violet are for proximity and control pilots.
Unfortunately, the unit I have doesn't show 12V from ground to any of the low voltage lines, which suggests to me that it's a brick. There's continuity between the ground wire and ground pin on a 14-50 plug, but that's about as far as I've gotten.
I checked that my meter works properly with a generic J1772 plug, but it's not clear to me if there needs to be some magic resistor combination somewhere to get the pilot signal, or if it's just dead.
Anybody have any experience with this?
I found one for $40 on eBay with a cable cut and would like to put a J1772 connector on it if it's not dead.
For the larger wires, it's pretty clear that the green is ground, I'd guess that blue is neutral or brown is hot.
As far as the low voltage lines go, my guess is that the white/orange in a pair are for the 3.3V source and that blue and violet are for proximity and control pilots.
Unfortunately, the unit I have doesn't show 12V from ground to any of the low voltage lines, which suggests to me that it's a brick. There's continuity between the ground wire and ground pin on a 14-50 plug, but that's about as far as I've gotten.
I checked that my meter works properly with a generic J1772 plug, but it's not clear to me if there needs to be some magic resistor combination somewhere to get the pilot signal, or if it's just dead.
Anybody have any experience with this?
davewill
Active Member
The pilot signal is a 1kHz square wave that goes between -12V and +12v. The duty cycle varies with the amperage being advertised by the EVSE. So you would not see 12V on your multimeter. Some 120V J1772s have been known to omit the negative part (although those don't work with Tesla's) which might be why you do get some reading on your J1772. You're going to need an oscilloscope to really see the signal.
While one of those wires may be connected to the proximity signal, that signal is driven by the car and is normally only connected within the handle. It's connected through a resister to ground within the handle and pressing the switch adds a second pulldown. That way the car sees the full voltage on the line when nothing's plugged in, a lower voltage level when you plug in and yet a different different level when the button is pressed. The EVSE itself generally does nothing with it.
While one of those wires may be connected to the proximity signal, that signal is driven by the car and is normally only connected within the handle. It's connected through a resister to ground within the handle and pressing the switch adds a second pulldown. That way the car sees the full voltage on the line when nothing's plugged in, a lower voltage level when you plug in and yet a different different level when the button is pressed. The EVSE itself generally does nothing with it.
That's only the case once the car has pulled it down to indicate desire to charge. When idle with no car connected it should be +12V DC.
Your point about CP not normally requiring a core in the cable is a good one however.
One possibility for extra core(s) is temperature sensing - I believe the HWPC(v2) has temperature sensing in the plug; possibly UMC(v2) has it too?
Indeed, I have no problem seeing +12V DC on a known working EVSE with no vehicle attached, and can't detect a PWM signal with my multimeter. This is consistent with the table here: SAE J1772 - Wikipedia
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