Charging on Dryer plug help....

[Motaskate]

Hi there. Im a model S owner who is trying to help out a friend on a budget to get level 2 240v charging from his dryer receptacle (10-30 i believe). I installed my charging outlet at home nema 14-50, and made an adapter for dryer pluga and with the model s you can draw down the current in the car for the outlet (using the 80% rule of course). Is the i3 capable of this. Can i create him a j1772 adapter to 10-30p dryer plug and use this to charge his i3 by drawing the current down from 32a to 24a? Or is this more involved? Im reading about the powerbox and is that what this product doea as the onboard systems cannot do this like the model s? Also, does the j1772 have to send the 1kW square wave to the car to communicate loads etc. and the powerbox performs this as well? How can he use the dryer plug on a budget all things considered if im doing the wiring. PS his electrical panel is in garage so installing a dedicated circuit and receptacle is an option as well... please advise...

-Josh

 

[Jeffj]

You can't just "wire up a J1772 to a 10-30 plug". An EVSE is required (basically an intelligent switch that talks the protocol and has safety features built in). There are inexpensive EVSE's that can plug into a 10-30 plug, you can build your own (google for OpenEVSE), or you can buy high-quality, but expensive "cable EVSE solutions" like the Jesla.

 

[alohart]

You couldn't charge your Model S from a dryer outlet using a cable with a 10-30 plug on one end and a Tesla charging plug on the other, either. All EV's need EVSE, for safety, if nothing else.

The i3 does support reduced amperage charging on Levels 1 (120 v.) and 2 (208-240 v.). But there are only 2 settings in iDrive for L2 charging: Maximum (32 a.) and Reduced (20 a.). To charge at 24 a., you'd need to set L2 charging to Maximum and set the EVSE to output a maximum of 24 a.

 

[jadnashuanh]

It is the pilot signal created by the EVSE that is set to indicate to the vehicle the maximum power that is available, then, the car knows not to exceed that value. As said, the i3's ability to limit its maximum draw that might differ from the EVSE signal is limited in a single step, and is not variable otherwise.

FWIW, the EVSE also has effectively GFCI built into it, and a safety interlock to remotely enable the power contactor to close. While not particularly complex, the car won't accept power coming in unless all of the hoops are jumped through. IOW, the EVSE is a smart on/off switch.

DC charging is a bit more complex, and the protocol differs from Tesla and CHADEMO, but has been accepted by many more manufacturers, so you will see more of the support in the future as new EVs show up.