The Bosch system is not standard yet, meaning it does not transmit via the usual protocols BT and Ant+. So, it does not allow third parties to receive in real time its sensors data: ebike, speed/cadence or power. Thus, you are stuck with their app and your mobile. You cannot use your Garmin or...
Thanks a lot!! So that means that for the rear we have 12V·0,1A = 1,2W available. That's a pity because that means we cannot plug there the Garmin varia eRTL615. This radar uses 12V but needs 1,5W according to its manual. If it only had 0,15A available, that would be enough!!