Originally Posted by mrjoeski
Quick update. After my last post, I took my voltmeter out to the car. The battery read 12.7 Volts. I started the car and read the system voltage at the battery and it was 14 volts, which makes sense as the battery would need a charge after a start. After 20 minutes of running the car, I tested the system voltage at the battery once again and it was still 14 Volts. There may be some truth to the battery needing to be registered when replaced. More to come tomorrow.
The alternator is supplying power after you start the car. So that's why you're getting a reading near 14v with the engine on. My car ranges from 13.8v to 14.4v programmed as a 70Ah AGM.
Before I had the car registered as a 90Ah lead acid and the voltage would go up to 14.8v.
These measurements were pulled from the OBDII port via the IBS sensor on the battery.