If the 12v battery is dead. The whole car is dead. Without power to the modules, the charging session will never initialize.I must be missing something here - If the 12V battery is maintained by the HV battery - suppose the HV battery goes dead for whatever reason, then the 12V battery goes dead. Why not just plug the car into a charger? Won't that start charging the HV battery, thus charging the 12V battery?
The contactors for the HV battery are controlled by the 12V electrical system.I must be missing something here - If the 12V battery is maintained by the HV battery - suppose the HV battery goes dead for whatever reason, then the 12V battery goes dead. Why not just plug the car into a charger? Won't that start charging the HV battery, thus charging the 12V battery?
I think I know what Darren is talking about and assuming the system works as intended......then the 12v battery shouldn't ever go flat. It would take quite a perfect storm of events to drain that thing without any sort of warning.When I saw the car on the Mach E tour earlier this month, the guy showing the car said they could not get into the car after it was stored over the holiday. I got the impression it was stored for a month and I don't think it was plugged in, so could not maintain the 12 V. He had to eventually figure out how to jump the 12 V to get in. Seems like if it's not plugged in, 12 V will drain quickly (especially in cold weather).
Here is an excerpt from the service manual. This appears to indicate the HVB is able to charge the LVB even when the vehicle is turned off and off plug. Do you read this the same way?It'll be interesting to see at which points the Mach-E does actually maintain the 12V battery. Most EVs maintain their 12V batteries, but not all the time.
I believe my i3 only maintains the 12V battery charge while the car is on and maybe while it's charging. If you let the car sit for an extended period, the 12V can definitely die.
The strategy for keeping the 12v system charged with the main HV battery was not finalized until after the pre-prod cars were built.I think I know what Darren is talking about and assuming the system works as intended......then the 12v battery shouldn't ever go flat. It would take quite a perfect storm of events to drain that thing without any sort of warning.
However, real world reports tell a different story. There are reports of the pre-production cars experiencing flat 12v battery which is contrary to how the system is designed. Maybe those are isolated cases and a valid explanation exists but until we learn of those details.....I will remain somewhat skeptical and cautious.
According to the documentation I have read, the door latch modules have an energy storage feature that allows them to open the doors even with dead 12v battery. The question I have is how can a 'module' operate without the 12v battery? The secondary question is how does that module received it's signal to open? Will it open for anybody or only for an authorized person. How is that person authorized.
The system is nearly identical to the Lincoln Continental hardware. The difference there is the Lincoln has place for a key. The MME does not. Maybe the engineers at Ford came up with a super clever system. I would have just put a key cylinder in the rear liftgate.
I guess we will see what happens in real world situations.
Thanks. That explains the issue with pp vehicles then....The strategy for keeping the 12v system charged with the main HV battery was not finalized until after the pre-prod cars were built.