# Hacking the Tesla Model S Rear Junction Box (AC Switching)



## Kevin Sharpe (Jul 4, 2011)

Cables and connectors...


----------



## Kevin Sharpe (Jul 4, 2011)

God damn it... another bloody micro


----------



## Tomdb (Jan 28, 2013)

Lol, so it only does switching of a single module.

So max of 7Kw on single phase with this box.


----------



## Kevin Sharpe (Jul 4, 2011)

Tomdb said:


> Lol, so it only does switching of a single module.
> 
> So max of 7Kw on single phase with this box.


Correct... in Europe the pre-facelift Model S was limited to 32A/7kW single phase regardless of whether it had one or two chargers installed.

I hope we can do better when we deploy the chargers in our conversions


----------



## Kevin Sharpe (Jul 4, 2011)

For the benefit of anyone reading this, here is what we know about the European version of the Tesla Gen 2 charger;

The single charger supports ~3.7kW (16A x 230V) single phase and ~11kW (16A x 230V x 3) three phase.

With the addition of the 'AC switch box' the single charger supports ~7.4kW (32A x 230V) single phase and ~11kW (16A x 230V x 3) three phase.

Dual chargers supports ~7.4kW (32A x 230V) single phase and ~22kW (32A x 230V x 3) three phase. In this configuration the 'AC switch box' is not required.


----------



## Tomdb (Jan 28, 2013)

With a micro it is dead easy to control those relays.

Trying to do it with analogue logic is more challenging. 


However an Attiny should be more then capable of doing the job, combined with 3 opto couplers for phase detection.

Would it be an issue to use a single relay with NO-NC contacts with the charger input as the common? 
I would use NC as the three phase connection.

There are some nice cheap beefy dpdt dual pole dual throw relays out there that would be more than capable.


----------

