Interesting device and in principle it can do almost the same as my gateway. But as I already mentioned: How will you externally control if data will be modified or not? Switch modification on/off? If you always modify then you will overcharge as the internal charger is no longer controlles by the car.
You could try to "hard-insert" the whole thing with a relais in the CAN-Bus. If you want to switch it off, you can then simply bypass it. This will lead to some errors on the bus but possibly the car tolerates that.
Fluence Z.E. seit 12/2015 | Corbin Sparrow seit 09/2011 | Kewet ElJet3 von 10/2005 - 02/2016 | Peugeot Scootelec