I've measured the 12v battery and it was about 13.5v. I have purchased Bimmerlink for battery registration. I tried to register it, but I wonder it was successful or not. When I first plugged in, I could see the battery was 99% on Bimmerlink, but I open BimmerLink after i3 produces all the beeping and errors, the battery status on BimmerLink was very low, starting only about 20% and now to 3%.SwissDI3 wrote: ↑Sat May 30, 2020 12:09 amMake sure your new 12V battery is charged.
Connect both batteries, plug charger into car, lock car if you can and let it sit overnight.
If that doesn't help, then try to clear any error codes with an app like bimmercode or carly.
If nothing works, then it might not have been only the 12V battery that gave you the problem in the first place.
Let us know what helped in the end!
The resting voltage of a fully-charged AGM battery at 77º F is ~12.7 V.
Thanks for the advice! The 12v battery seems to be drained now.alohart wrote: ↑Sat May 30, 2020 10:46 amThe resting voltage of a fully-charged AGM battery at 77º F is ~12.7 V.
If you measured the battery's voltage while it was installed in the car, you were likely measuring the output voltage of the DC-DC converter that charges the 12 V battery unless the high-voltage disconnect was disconnected. The DC-DC converter turns on when a door, the frunk, or the hatch is unlocked or opened.
If you had recently charged the 12 V battery with a battery charger before you installed the battery, you might have measured its voltage before the resting voltage was reached (several hours after charging).
If you're still having problems, disconnect the negative 12 V battery cable and measure the battery's voltage at its terminals the following morning.
The East Penn battery that I bought had about a 50% charge. I doubt that many sellers fully charge 12 V batteries before selling them. An AGM battery like the AUX18L has a low self-discharge rate but needs to be recharged at least annually. My battery had been manufactured over a year before I bought it, so I'm guessing that it had never been recharged before I bought it.