J1772 charging blues

[djp]

UMC to J-1772 to charge a BMW i-3 I have a roadster Sport and just purchased a BMW i-3 which uses J-1772 charging. I wonder if I can buy an adapter for my UMC to J-1772 to let me charge the BMW without having to invest in a 40 amp (like Clipper Creek) charger for the BMW. I only need to charge one at a time, and actually have an extra UMC if the adapter is more permanent, or difficult to swap. Any body know the scoop on this? Hasn't somebody wanted to charge their model S from a UMC? I gather the standard is the same....

No, an adapter from the Roadster connector to J1772 doesn't exist. One option is to get a J1772 station along with @hcsharp's CAN JR (J1772 to Roadster adapter). Or just add a Clipper Creek as a second station.

In theory you could cut the Roadster connector off the UMC and splice on a J1772 connector, if you have the requisite electrical skills. Besides the shape of the connector the electrical and signaling standard is the same.

There is a company that converts Model S UMCs to J1772, but I'm not sure if they'll convert a Roadster UMC.

UMC conversion to J1772 (JESLA)


Tesla sells a Roadster to Model S adapter, but that doesn't help you with the i3.

 

[dhrivnak]

I hear it can be done and I think Tom Saxton among others did it. Since the Roadster only has one pilot signal where j1772 has two I assume you only need the power signal wire.

 

[ravng]

The roadster only has the "Charge pilot" signal and not the "proximity pilot" signal. In J1772 the proxmity signal is optional, while in EU version this signal is used to tell the charging station about how many amps the cable can do (in EU most charging station does not have a thetered cable but a "type 2" connector instead).

So a long story short: For j1772 you can skip the Proximity signal, in EU you need to ground the proxmity signal thru a resistor (220 ohms for a 32A cable).

Please not that you cannot leagely splice the cable (j1772 connector must be without power when not connected to a car).
If you have the skills needed you can go for the open-source Hydra solution: https://www.tindie.com/products/nsayer/j1772-hydra/
Or, get two standard J1772 charge stations, and limit them as needed.