In theory it actually isn't that hard. Without checking, if my memory is correct, all it is, is a correct resistor between one of the signal pins and ground to signal the maximum amperage draw. BUT the tricky part is that the only place you have access to the signal pins is the adapter part that plugs into the shorter UMC cable. ie. it is the short stubby Tesla 14-50 and 5-15 adapters that have those resistors in them. To make a "real" 14-30 adapter, for example, you'd have to make a connector that mated perfectly with Tesla's proprietary UMC plug. That just isn't going to happen.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
sublimaze1
8Dec2012 / Leeroy Jenkins
Nice find! I had used an "engineered" cheater line (I know, I know, Bad Bad Bad boy) for when I parked on that side of the garage. Guess I can make the UL approved upgrade now.
mitch672
Active Member
I've also ordered it, along with a few 5-20 female tails from "StayOnline". My plan is to makeup a 6-20 (20A 240V, commonly found in hotel air conditioners) to 5-20 adapter (it will work, the car will get 240V @ 16A). I'm also making up an L6-20 to 5-20 cable as well, that's similar, but a twistlock 240V @ 16A, commonly found with any Nissan Leaf owner who upgraded their EVSE to 240V.
This adapter is Teslas first 20A adapter, which will set the Model S correctly to 16A
Here are their "cord cuts" (molded connector on 1 end, bare cut cable on the other end) notice they have 5-20 females in various lengths between 1' and 6'
Unterminated Cord Cuts
This adapter is Teslas first 20A adapter, which will set the Model S correctly to 16A
Here are their "cord cuts" (molded connector on 1 end, bare cut cable on the other end) notice they have 5-20 females in various lengths between 1' and 6'
Unterminated Cord Cuts
It says 4 mph, although I'm getting a bit of voltage drop on the outlet I'm plugging into: 16A @ 112V down from 120V.
efxjim
Member
Here is my modification. This is for testing only!:wink: It will let you set the max current that the charger thinks the adapter will supply. I routed a groove between the ground and the pilot pin. Inserted a 1/8 Watt resistor (the value you will need to interpolate from existing adapters). If you are going to attempt this you should have this minimal knowledge. The leads are small enough to not stress the sockets. Mine sets the level at 20A so I can charge off of studio generators on location. This is a supervised situation. The value can be set lower in the car. If your power supply is of very good quality the adapter just gets mildly warm.
@efxjim - which adapter did you modify? The 5-20? THat's a cool idea. I take it the resistor will be in parallel with the embedded resistor in the adapter. I'm not at home, so I can't check resistance values, but is it higher values give you more amperage, or lower values?
For those of you playing along with the home game, note the 3 warnings provided... and be sure you're comfortable with the fact that if your car burns up while charging using this has liability and insurance implications as applicable.
islandbayy
Active Member
So your saying, if one were to plug either the 5-15 or 5-20 adapters into 240v outlets, it would still let you charge, only still capped at 12 & 16 amps? That would be awesome for me, as I have a location I can plug in for free, and I can convert the outlet to 240, (Change the actual outlet, and change the breaker to make it 240v).
W00T
mitch672
Active Member
I'm saying using the new Tesla 5-20 120V adapter for the UMC, that sets the pilot signal to the Model S to "16A", for use on a 20A dedicated circuit. The car doesn't particularly care if it's given 120V or 240V through that adapter... Of course with 240V, the charging speed is doubled over 120V. What I am simply doing is building adapter to plug in a 6-20 20A 240V and an L6-20 20A 240V to that adapter. Since this is Teslas first "official" 20A adapter, to set the pilot signal properly... You could have built adapters like this before, but you would have had to use one of the UMCs 30A or 50A adapters, and remembered to dial down the charging current to 16A in the car. The new adapter removes that requirement...
Oh, please don't do this, it violates code and can create a pretty serious issue, including fire.
From personal experience I can tell you that plugging a 120V Shop Vac into a 5-15 outlet that provides 240V makes one hell of a whooooshing noise for all of 5 seconds until it burns up and smokes like mad. After diagnosing the problem, I found that someone had installed an outlet onto a previously abandoned 12/2 Romex cable in the wall, and the previous owner of the property failed to properly remark the white wire to black or red indicating 240V.
If you insist upon doing this, install a PROPER 6-15 or 6-20 outlet, then make an adapter - LABELED PROPERLY per the FAQ - that has a 6-15 or 6-20 plug and a 5-15 or 5-20 receptacle, into which you can plug the proper UMC adapter. This way, the outlet will conform to standards and the only non-standard piece will be a properly-labeled adapter cord.
Note that there are liability and insurance implications with using any non-standard adapter cord and be comfortable with those implications before doing so.
islandbayy
Active Member
Yes, I know, thats why I said I'd change the outlet, as in change the outlet to reflect the equivalent 20 amp at 220/240v.
I have no problem building adapters, I've made plenty already. Extension cord adapters to be more specific. Currently building surge protector cords as well. I just have not experimented with the 120v adapters yet.
OK, good. I saw you say "plug the 5-15 or 5-20 adapters into 240V outlets". The only way you can do that is to put 240V to a 120V form-factor outlet (NEMA 5). Install a NEMA 6 series and you'll be good. If using Romex, don't forget to remark the white conductor with black or red tape, lest someone blow up a Shop Vac in your home later.
efxjim
Member
Yes, adding more resistance increases the allowed charge current. Like the roadster 110 charger you could take the adapter up to 16A for use on a dedicated 20A breaker.
So I'm still not sure which adapter you modified in the picture you posted. Was it a 14-50 adapter or a 5-20 adapter?
Based on what you said above, if you add a resister in parallel with the embedded resistor, all you'll be able to do is decrease resistance, which would reduce allowable charge. So I'm guessing you modified a 14-50 adapter down to 20 amps?
efxjim
Member
I modified a 5-15 adapter so it could charge at 20a. Adding a resistor to the 5-15 adapter will raise the amps available.
Similar threads
- Question
