In what circumstances do you plan to use this device? Indoors and outdoors? Only at known locations where you are confident regarding the wiring? I'd be a bit leary of running long extension cords and connecting them overnight.
Do you think that such a device would work equally well, or be as safe, with Roadsters, Model Ss versus the Leaf?
Like TEG, I built my own as well. Lots of detail on how to do it in this thread on mynissanleaf.com:
My Nissan Leaf Forum View topic - Do It Yourself: 240v from two 120v sources
If you're not comfortable working with high voltage, I don't recommend you build your own but pay the quick220 guys to do it for you!
I plan on using it in areas where there aren't any handy 240V outlets and charging at 120V/12A will mean too long a wait.
I would make sure the box stays indoors - at least mine isn't outdoor rated.
Aim to have both plugged into 20A circuits which is safe for up to 16A charging. Garges, laundry rooms and kitches are good locations for finding 20A circuits, although they can't be GFCI protected as the device will trip GFCI since it only uses the hot line from each circuit thus leading the GFCI to think there's a large ground fault since no return current goes over the neutrals.
On 15A circuits, limit current to 12A (though in theory 16A is OK for short periods of time).
As always make sure the receptacles are in good shape - I would limit extension cord use to no more than 25ft.
With a volt meter in the device one can check voltage drop when the car starts charging which services to verify that wiring is OK!
There really is no more issue using one of these than using L1 120V charging - the amount of current pulled through each is similar - so if you are confident charging on each outlet at 120V/12A, then you are good to charge 240V/12A and are able to charge twice as fast.
