12 V battery - why?

[TomT]

Originally it was going to be 48 volts to gain more advantage. Later they dropped it to 36 because of the aforementioned issues... Even at that, it died... I don't know why as it seemed a good idea. Perhaps partly because of the incompatibility with virtually everything else out there.

Looking around, it appears that it was a 42 volt system, just as current cars are a 14 volt system. This kept the charging voltage around 42 volts, and was a "36 volt" battery. The voltages were all 3 times current values for 12 volt systems.

 

[Nubo]

This isn't a deep-cycle issue. It's an improper charge level issue. Unless AGM doesn't care about being half charged, I don't see how this solves the problem. There must be some attribute I don't know about.

There is a deep-cycle issue separate from any charge-voltage parameters. Long periods of *no* charging during which the battery is slowly draining. This is exacerbated by periods of high current demands during telematics and also because top-off charging during extended parking does not happen if the car is plugged-in.

 

[gbarry42]

I see. So, maintaining the battery at 60% charge is kind of like one big four year long deep cycle :roll:

 

[Nubo]

I see. So, maintaining the battery at 60% charge is kind of like one big four year long deep cycle :roll:

You're confusing cause and effect. But this is really OT for this thread and my fault for taking it off track.

 

[2k1Toaster]

Originally it was going to be 48 volts to gain more advantage. Later they dropped it to 36 because of the aforementioned issues... Even at that, it died... I don't know why as it seemed a good idea. Perhaps partly because of the incompatibility with virtually everything else out there.

Believe me, it is not dead...

And some of the new designs will make it nearly impossible to do even simple car modifications because of the data and power distribution networks. It is super cool from an engineering standpoint. Irritating from a consumer level car hobbyist viewpoint.

 

[TomT]

No, not today, but it was for MANY years after BMW first proposed then dropped it... The technology is much different today than it was then.

Originally it was going to be 48 volts to gain more advantage. Later they dropped it to 36 because of the aforementioned issues... Even at that, it died... I don't know why as it seemed a good idea. Perhaps partly because of the incompatibility with virtually everything else out there.

Believe me, it is not dead...