Adaptor that takes 2 of J1772 @ 40/32 A and supplies a model S 80 amp charger?

[PeeBee]

Hi there,

I have a dual-charger Model S.
Has anyone built an adaptor that connects to 2 of 40 A charger plugs and plugs into an 80 Amp capable Model S?

 

[gaswalla]

That would be cool... Talk about annoying the i3 owners when they pull up to a dual head j1772 public charger and see you pulling in juice from both!

 

[K-MTG]

This would be a cool gadget...I wonder how difficult it would be to make.

 

[andrewket]

It’s been done.

Two 120v outlets, two 240v outlets. J1772 should be the same. 120v is easy on different phases. 240v is more involved.

Quick 220 Systems: Quick 220 Systems 20 Ampere Straight Blade Outlet

 

[K-MTG]

It’s been done.

Two 120v outlets, two 240v outlets. J1772 should be the same. 120v is easy on different phases. 240v is more involved.

Quick 220 Systems: Quick 220 Systems 20 Ampere Straight Blade Outlet

But this is to double the voltage...what about doubling the amperage?

 

[rypalmer]

Very problematic unless the device can confirm both chargers are fed by the same phases.

 

[dave4444]

What you're asking is certanly buildable, however it would be quite complex.

First, you'd need to handle the pilot signaling to each source reading the max AMPs allowed plus trigger the charger, plus trigger start/stop etc..

Second, you'd need to provide pilot signaling to the car which is the sum of both chargers (this would need to be updated in real-time if one of the sources changes on the fly while charging), and do the J1772 protocol between to the car.

Third, you'd need to draw no more than each charger allows, this may require circuitry to limit each charger individually. You also need to prevent back-feeding a charger from the other. If one shuts off due to fault or GFCI you better not feed it from the other charger!

Forth, you'd need to isolate each charger as they can be different voltage and phase. Best case, they are the same phase(s) and only a few volts apart, worst case they are different phases of a 3-phase building supply (Charger #1 is A-B LL, Charger #2 is B-C LL, etc...) or split-phase but one is wired backwards. This can get complicated, worst case you may need to shift between phases, possibly AC->DC->AC. Not worth it at that point.