[Prohunter]

My 2020 m50i has sat for over 6 months. I replaced the battery and drove to the shop to get it registered. On the drive home while cruising at 70 the car shut off and everything g went black. No lights no engine nothing. I coasted to the shoulder and hooked up my noco so I could open the tailgate. Nothing I tested the terminals without the noco and got 12.7 volts but nothing in the car worked. Completely dead. I had no warning lights or messages before this happened. Any ideas? The truck has a little over 14k miles

[ted920]

So Sorry That This Happened to You.

Very Scary.

Curious what the Cause & Solution is.

[maher]

Sounds like the ground terminal connector on the battery wasn’t tightened properly.

[Spiker01]

Is it possible that it was the wrong size battery and the terminals shorted when you closed the lid?

I have also heard that the battery needs to be programmed/registered. Maybe it shut off for that reason?

[Marty in NY]

Originally Posted by Prohunter

My 2020 m50i has sat for over 6 months. I replaced the battery and drove to the shop to get it registered. On the drive home while cruising at 70 the car shut off and everything g went black. No lights no engine nothing. I coasted to the shoulder and hooked up my noco so I could open the tailgate. Nothing I tested the terminals without the noco and got 12.7 volts but nothing in the car worked. Completely dead. I had no warning lights or messages before this happened. Any ideas? The truck has a little over 14k miles

That's scary just reading it! Well, you had it for 14K miles and I assume that never happened until you were on your way home from having the battery registered, right? Who installed the battery? I can only think that either who ever installed it did not properly tighten both terminals or something related to the install or something happened during the registration process but that is a stretch since that only manages how the battery is charged but until you know the root cause, anything is possible.
I have the original battery and I was on my way back home from a 5K mile trip a few weeks ago and have about the same mileage on mine as you do and like you doing 70 on the highway when all of a sudden my dash and display went totally black. The car didn't skip a beat though and after about three seconds the dash and display came back on like nothing ever happened. These things freak me out, it's always been electronics on my BMW's that are flaky.

So, how did your story end?

[Qsilver7]

Until we get more info...I'm inclined to think that the battery lost contact somehow.

If you didn't install the battery yourself...then there's a reference that is missing and you may just need to lift the stuff out of the way and double check all the connections.

And not just the connections but the battery hold downs, too! (see pics below from my f06 6 series) The hold down's can be easily overlooked or improperly replaced which can allow the battery to move as the vehicle goes over bumps, around corners, and stop/start situations. This movement can loosen the pos/negative terminals or other connections.

And some battery setups have multiple connections...there can be up to six positive connections and two negative connections...and one must make sure those connections are reinstalled correctly.

Good luck...and post back any updates.