Adapter to combine two 30A level2 into one 60A J1772 - faster charging

[driver_EV]

I often see multiple EVSE units both unused and offering only 30 Amps or so.
What if someone created an adapter box with a little extra amount of smarts built-in that could safely combine (parallel) the two 30/32A EVSEs into one 60/64A EVSE connection for faster charging of Roadster?

In principle, the two side-by-side EVSEs will almost certainly be from the same transformer feed (this can be detected by the adapter circuit) and if the power at the two J1772's are out of phase, (one is 180 degrees out), then the adapter can simply utilize a DPDT relay circuit to flip the phase on one supply, to put the two in parallel, and verify they are safe to combine.

Presto change-o!
DIY ~70A Level2 !

[dhrivnak]

I wanted to float an idea about the possibility of making an adapter that could combine two 30 amp J-1772 plugs into a 60 amp option for the Roadster. While I have found MANY J1772 options they all have been limited to 30 amp. I know in theory one should be able to combine the legs assuming they are on the same phase. I think this would be typical for 240 installations but not sure one could count on this with 3 phase power (208V) that I find at many businesses. I know one would need to test the legs first to ensure they are the same phase but does anyone see other problems with this concept? Would I likely be able to build an adapter box?

With the slow rate of 30 amps while on a road trip and me normally being the only car to be charging such a combiner box would be most helpful.

Thank you

[TEG]

I suggested a while back that perhaps EVs should start coming with dual sockets so you could plug both in at once.
It would make sense for Model S which already has a logical charge flap location symmetrically on the other side of the car.
Plus they have a dual charger option. So why not make it so model S can accept two J1772 plugs at once (one to each side of the car) ?
Each socket could go to a different charger box that run in parallel...

If someone parks next to you and needs to charge they could remove one cable and still leave you charging at 6.6kW.

[rolosrevenge]

Parallel charging of batteries is tricky because even though the equipment may be "identical" variations in production tolerances will cause circulating currents and strange voltages and whatnot. I'd advise against trying things like that.

[VolkerP]

TEG suggests a setup similar to the Tesla supercharger which consists of 9 single-phase 10kW charging units similar to the Model S on board ones. The supercharger feeds on 3 phase AC so different AC phases are used. But the output is one DC circuit.
So it might be tricky but Tesla is about to do it.

[TEG]

Even the 20kW option in Model S consists of two 10kW chargers. It is just that the standard way would take one 60amp+ input instead of two (individual) 30amp inputs...

[smorgasbord]

I suggested a while back that perhaps EVs should start coming with dual sockets so you could plug both in at once.

Kind of like the old Jaguar XJ's that had two gas filler caps. Great for cannonball runs! (or, so I've read).

[TEG]

Kind of like the old Jaguar XJ's that had two gas filler caps.

Been there, done that:
What charge port connector?

[Eberhard]

and for the european version, there will be a third 10kW charger, each been connected to e different phase from the 3-phase socked - why not to connect to two different sources - simple double the charging power?

[jerry33]

Kind of like the old Jaguar XJ's that had two gas filler caps. Great for cannonball runs! (or, so I've read).

My Land-Rover Series III had two gas caps, two gas tanks, and two padlocks (to keep other Land-Rover owners from borrowing the gas caps).