czum09

I'm aware that continuous battery drain is a relatively common issue on these cars. My car was dead a couple of days ago, started, got red battery message, bought a new battery.

Well, got the message again today on the way home......

A few days before on a 40 minute drive, my headlights flashed, on/off/on. On start up, the cluster lights look like they are pulsing, almost like fluid. AND over the last couple weeks, I've noticed the volume on Command seems to fluctuate up and down while sitting at a light, or letting the car worm up.

I'm guessing it is the voltage regulator, but maybe someone who has had similar issues can chime in. I'll be doing some trouble shooting as soon as I can.

Crissus

Just measure the voltage at your battery while the car is running.
Should be around 14.0-14.8 Volts. Anything below and the regulator is dead.

Welwynnick

I'm pretty sure the max charging voltage should be 14.4 V.
In practice it can be anywhere from 13.2V to 14.4, depending on battery state.

The lowest voltage you should see is 12.4V with no charging and no discharging. If you let a battery discharge any lower than that, it will cause damage to the battery. Keep it above 12.4 all the time and it will last years (as long as you're not in AZ etc).

If you see behaviour like that when the engine is running, then yes, that sounds like the voltage regulator. I would check it out ASAP. If the alternator voltage goes too high it will take out all your electrics. Bye-bye car.

Nick

czum09

Checked the voltage when I got home the other night, car off, it was 11.4v..... Car started fine, drove home fine, but got the check battery message. If the car drains the battery while driving, I can only assume VR. I should have a multi meter tonight to check it.

BTW, car has been sitting for two days, interior lights work and soft close is working.

corsaschnell

Did you by any chance jump start the car with the original bad battery?

czum09

Yes.

Basically I got in the car and it started fine. Hit my heated seat, which started blinking. So, I thought shutting the car off would reset it. It didn't, then the car wouldn't restart. Got the typical drainage of lights etc. jumped it, and it didn't want to stay running. Auto store said the battery had zero charge. It was the original.

czum09

Well started the car up and noticed a plastic burning smell from under the hood. I'm assuming alternator. Voltage was low 11.4v ish. Goes up to about 11.8-9v with small revs.

czum09

Took the alternator out to get checked, scared the lady at the parts store because it binned up so bad. Replaced alternator (Bosch remanned) and have driven 300 miles with no issue. Voltage is constant around 14.0v. Very happy!