So we know about big battery. What about small battery. As soon as I saw new placement of HV electronics, I'm thinking about change in 12V system design. It is possible, now, to tap into HV with disconnected contactor. That means that it is possible to not have 12V battery at all. I don't know what Tesla did, but if I had DC-DC converter inside the HV pack, I would definitely skip 12V battery and rather have two DC-DC converter circuits. One being online forever (down to 250V) capable no more than an amp or two just for telematics (GPS, LTE, BT, NFC) and alarm. Main DC-DC circuit (not enabled if vehicle is asleep) There is no reason to charge/discharge/monitor 12V battery. It is constant inefficiency. Plus, as we all know, lots of problems with 12V batteries going bad or empty. This new solution would have many weird advantages. For example: It would be possible to complicate theft: imagine GPS+telematics that can not be unplugged easily. It would be possible to leave the vehicle in the parking lot unplugged for a year. Small DC-DC converter can be way more efficient than solution Model S/X has. Imagine 30mA load, with high efficiency (40mA draw from HV pack as the worst scenario) That is 12,5Wh per day. Up to 0,4kWh per month. Piece of cake for 50kWh pack. My BMW with massive 12V battery has theoretical 1.0-1.2kWh of energy. It would be possible to add a solar panel that actually makes sense (not going crazy with area). Though it would not add any considerable range daily, it would be able to run vital functions indefinitely if parked outdoors: this includes telematics, alarm. Even ventilation. All it needs is always on, high efficiency, low power (remember that 1-2A DC-DC thingy) converter. It would be considerably cheaper. In addition to removal of 12V battery, there would be considerably less copper on 12V system. Less maintenance. This would simplify switching to switch to 48V system in the future (promised on Model Y?). Power steering pump, rear window heater, coolant pump, cabin air fan, outside radiator fan, wiper motor - they are all in desperate need to switch to 48V as soon as possible. With this design, it would be possible to just add those components one by one. Just add 48V output circuit under the rear seat and slight change in wiring harness. Ran out of time. There is a lot more to tell. Can anybody name few disadvantages.