Battery discharge / voltage draw when car is turned off

Kaufboy · 07-01-2023, 01:50 PM

I have a 2013 BMW X1 (original owner and luckily haven't had too many issue yet). It has an OEM 80 ah AGM battery which is about 4.5 years old. I use a CTEK MUS4.3 battery charger to charge the battery when the car isn't driven much (I don't keep it connected, I just charge the battery if the car hasn't been driven for several weeks.) I have been trusting that when the CTEK shows the battery can take a charge, hold a charge and is fully charged that the battery is charged.

I just tested the voltage of the battery after reaching a full charge (per the CTEK charger) and it reads 12.6V with a multimeter with the car locked. I would think that a fully charged battery should be near 12.6V so that is good, but I ran into a problem which I will explain later. With the car open but without the key in the ignition the battery voltage drops to 12.3V. With the accessory mode turned on so that I can use the OBDII port, but the engine off, the voltage drops to 12.16V. (These readings are directly after charging and before the car has been started.)

Is a voltage drop down to 12.2V with the ignition switch on normal? Shouldn't the voltage on this battery be higher than a standard 12.6V due to the start/stop feature and lots of electronics? (I haven't started the car again yet to test the battery with the engine running.)

I hadn't tested so specifically in the past so I have no baseline for what is normal with the electrical draw on the battery

Before recently charging the battery, I had a problem that when start/stop turned the engine off at a stoplight and then turned it back on there was a engine malfunction message and the car went into limp mode. I struggled to get the car to the side of the road. I then turned the car off. I waited a few minutes and turned the car on again and it ran normally for a short distance (about 2 1/2 miles) before the engine malfunction message returned and the car started to run roughly so I drove another 1/2 mile home and parked the car in the garage.

After fully charging the battery, engine started normally and was able to be backed out of the garage (we needed to move the car momentarily). When I went to put the car back in the garage, the engine turned over very slowly, the engine malfunction message reappeared and the car immediately went into limp mode. I drove it slowly directly back into the garage. I tested the battery voltage with the car off but in accessory mode using an OBDII scanning live reading and it only read 11.6V. (I didn't test with a multimeter yet.)

I am trying to figure out if the issue is could be only caused by the battery, or if it is surely a sign that the alternator or an electronic module has gone bad. I don't plan on working on the car myself, but at the moment I am afraid to turn the car back on to try to start it for fear that if the alternator is bad or is try too hard to charge the battery that it might damage some electronic module (if that hasn't already happened).

Can a bad battery by itself cause such problems even if the alternator is good or is the engine malfunction like described a sign that the alternator or maybe an electronic module has gone bad?

Also, this is my first post at Bimmerpost. I couldn't find a general forum for such general questions that are not BMW model specific. If there is somewhere better to post general questions, place let me know.

Kaufboy · 07-01-2023, 08:11 PM

Update - after about 6 hours the battery's charge has dropped to 12.2V without any load (car locked), and is now 11.8V with accessory load. When I turn further turn on the headlights the battery fluctuates between 11.2V and 11.6V and makes a beeping sound as well as the sound of a switch. (I only turned on the headlights momentarily to test the voltage and turned them back off. The parking lights came on, but the headlights didn't until I switched from headlights on to auto mode.)

I think that the battery is clearly failing, but I would like to know what voltage readings would be normal to see with a good battery. I also would like to know if anyone has had such a significant issue as going into limp mode just from a failing/bad battery. My experience with other cars is that if the battery car be jumped then the car usually runs (off the alternator) until it is shut off.

0w40X1 · 07-01-2023, 11:14 PM

I have a 2014 X1 s28i with 40k miles, and you describe just how my battery acts, but has always started car. I only know the voltage since I run with Scangauge to see real MPH, coolant temp, voltage, and MPG.
Battery can be charged 12.6 and minute it turn on radio without running it's 12.3. Run radio for 10 minutes and gauge might say 12.0 or 11.9.

I'm not sure if battery was damaged whileshipping 10 years ago or they are just not very many reserve amps, but it works without any starter drag.

My battery is original 10 year old, and I keep charged maybe once a month when in US, and disconnect for 2 months when I leave. I come back and reconnect and it looks still charged since it charges at 13.7 instead of up to 14.7.

I never use the start stop, and have measured idling use of fuel to be 1/4 gallon/hour.

I have eye on a Sam's club AGM when times comes, but not , yet.

Kaufboy · 07-02-2023, 12:18 AM

Wow, the battery lasted 10 years. That is amazing. I have never heard of a battery lasting that long. My first battery only lasted 5.5 years. I thought I would get 5 years out of this battery, but my battery has definitely failed at 4.5 years.

I usually turn off the start-stop as soon as I start the car, but sometimes I forget.

I tested again and this evening and just sitting for 12 hours the battery now read 12.35V with the doors lock and everything off and 12V with the doors open but no key in the ignition slot. 11.9V with the key in the slot. The car also now won't start with the current charge.

I will charge it again to see if I can get the car started. Without being able to start the car there appears to be no way to get the car into neutral.

Next would be seeing if I can jump start the car (with a portable battery jump starter) to get it into neutral.

The owner's manual has instructions for how to override the selector lever lock on the Steptronic 6-gear but there are no instructions for the Steptronic 8-gear the instructions for the 6-gear are useless since there is no red lever down in the compartment under the gear selector.

There are many videos on-line for how get a BMW with an electronic gear selector into neutral when the car won't start, but none apply to my 2013 X1.

I think it is insane that BMW would make it so hard to get a car that can't be started into neutral.

07-01-2023, 01:50 PM	#1
Kaufboy Registered 0 Rep 3 Posts Drives: BMW X1 Join Date: Jul 2023 Location: USA iTrader: (0)	Battery discharge / voltage draw when car is turned off I have a 2013 BMW X1 (original owner and luckily haven't had too many issue yet). It has an OEM 80 ah AGM battery which is about 4.5 years old. I use a CTEK MUS4.3 battery charger to charge the battery when the car isn't driven much (I don't keep it connected, I just charge the battery if the car hasn't been driven for several weeks.) I have been trusting that when the CTEK shows the battery can take a charge, hold a charge and is fully charged that the battery is charged. I just tested the voltage of the battery after reaching a full charge (per the CTEK charger) and it reads 12.6V with a multimeter with the car locked. I would think that a fully charged battery should be near 12.6V so that is good, but I ran into a problem which I will explain later. With the car open but without the key in the ignition the battery voltage drops to 12.3V. With the accessory mode turned on so that I can use the OBDII port, but the engine off, the voltage drops to 12.16V. (These readings are directly after charging and before the car has been started.) Is a voltage drop down to 12.2V with the ignition switch on normal? Shouldn't the voltage on this battery be higher than a standard 12.6V due to the start/stop feature and lots of electronics? (I haven't started the car again yet to test the battery with the engine running.) I hadn't tested so specifically in the past so I have no baseline for what is normal with the electrical draw on the battery Before recently charging the battery, I had a problem that when start/stop turned the engine off at a stoplight and then turned it back on there was a engine malfunction message and the car went into limp mode. I struggled to get the car to the side of the road. I then turned the car off. I waited a few minutes and turned the car on again and it ran normally for a short distance (about 2 1/2 miles) before the engine malfunction message returned and the car started to run roughly so I drove another 1/2 mile home and parked the car in the garage. After fully charging the battery, engine started normally and was able to be backed out of the garage (we needed to move the car momentarily). When I went to put the car back in the garage, the engine turned over very slowly, the engine malfunction message reappeared and the car immediately went into limp mode. I drove it slowly directly back into the garage. I tested the battery voltage with the car off but in accessory mode using an OBDII scanning live reading and it only read 11.6V. (I didn't test with a multimeter yet.) I am trying to figure out if the issue is could be only caused by the battery, or if it is surely a sign that the alternator or an electronic module has gone bad. I don't plan on working on the car myself, but at the moment I am afraid to turn the car back on to try to start it for fear that if the alternator is bad or is try too hard to charge the battery that it might damage some electronic module (if that hasn't already happened). Can a bad battery by itself cause such problems even if the alternator is good or is the engine malfunction like described a sign that the alternator or maybe an electronic module has gone bad? Also, this is my first post at Bimmerpost. I couldn't find a general forum for such general questions that are not BMW model specific. If there is somewhere better to post general questions, place let me know. Last edited by Kaufboy; 07-01-2023 at 03:33 PM.. Reason: Improved explanation of issue
	Appreciate 0 Tweet Quote

07-01-2023, 08:11 PM	#2
Kaufboy Registered 0 Rep 3 Posts Drives: BMW X1 Join Date: Jul 2023 Location: USA iTrader: (0)	Update - after about 6 hours the battery's charge has dropped to 12.2V without any load (car locked), and is now 11.8V with accessory load. When I turn further turn on the headlights the battery fluctuates between 11.2V and 11.6V and makes a beeping sound as well as the sound of a switch. (I only turned on the headlights momentarily to test the voltage and turned them back off. The parking lights came on, but the headlights didn't until I switched from headlights on to auto mode.) I think that the battery is clearly failing, but I would like to know what voltage readings would be normal to see with a good battery. I also would like to know if anyone has had such a significant issue as going into limp mode just from a failing/bad battery. My experience with other cars is that if the battery car be jumped then the car usually runs (off the alternator) until it is shut off.
	Appreciate 0 Quote

07-01-2023, 11:14 PM	#3
0w40X1 Lieutenant 34 Rep 485 Posts Drives: 2014 BMW X1 s28i M Sport Join Date: Sep 2013 Location: West Texas iTrader: (0)	I have a 2014 X1 s28i with 40k miles, and you describe just how my battery acts, but has always started car. I only know the voltage since I run with Scangauge to see real MPH, coolant temp, voltage, and MPG. Battery can be charged 12.6 and minute it turn on radio without running it's 12.3. Run radio for 10 minutes and gauge might say 12.0 or 11.9. I'm not sure if battery was damaged whileshipping 10 years ago or they are just not very many reserve amps, but it works without any starter drag. My battery is original 10 year old, and I keep charged maybe once a month when in US, and disconnect for 2 months when I leave. I come back and reconnect and it looks still charged since it charges at 13.7 instead of up to 14.7. I never use the start stop, and have measured idling use of fuel to be 1/4 gallon/hour. I have eye on a Sam's club AGM when times comes, but not , yet.
	Appreciate 0 Quote

07-02-2023, 12:18 AM	#4
Kaufboy Registered 0 Rep 3 Posts Drives: BMW X1 Join Date: Jul 2023 Location: USA iTrader: (0)	Wow, the battery lasted 10 years. That is amazing. I have never heard of a battery lasting that long. My first battery only lasted 5.5 years. I thought I would get 5 years out of this battery, but my battery has definitely failed at 4.5 years. I usually turn off the start-stop as soon as I start the car, but sometimes I forget. I tested again and this evening and just sitting for 12 hours the battery now read 12.35V with the doors lock and everything off and 12V with the doors open but no key in the ignition slot. 11.9V with the key in the slot. The car also now won't start with the current charge. I will charge it again to see if I can get the car started. Without being able to start the car there appears to be no way to get the car into neutral. Next would be seeing if I can jump start the car (with a portable battery jump starter) to get it into neutral. The owner's manual has instructions for how to override the selector lever lock on the Steptronic 6-gear but there are no instructions for the Steptronic 8-gear the instructions for the 6-gear are useless since there is no red lever down in the compartment under the gear selector. There are many videos on-line for how get a BMW with an electronic gear selector into neutral when the car won't start, but none apply to my 2013 X1. I think it is insane that BMW would make it so hard to get a car that can't be started into neutral.
	Appreciate 0 Quote