X5 e53 battery drain???

[andrewwynn]

Because it's reading the resistance losses from any draw coming from the battery.


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[StephenVA]

Originally Posted by oldskewel

Great stuff, generic instructions for almost any car.

What are the best ways to do all the above on an E53 while dealing with the battery in the trunk and the sleep mode? Will the rear hatch being open prevent sleep mode? How to turn off courtesy lights, alarm?, etc.?

Alarm off, doors and hatch closed, lying on the folded down rear seats, reaching down into the battery area, ... ? Or something else?

I expect there are some clever things to make this easier than it seems.

Listed below are the best posts that will help you find systems that are still drawing amps and voltage AFTER the key is off.

BMW Vehicle Parasitic Draw Testing
When your car battery goes dead overnight, usually either the battery is at the end of its life span, or you left something on, such as a light. Occasionally something is drawing power that's not of your doing. This is a parasitic draw, and it can cause the same result as leaving the headlights on: a dead battery in the morning.

1. Remove the negative side battery cable from the negative battery terminal.
2. Connect the black wire to the com input on the multimeter and the red wire to the 10A or 20A input on the multimeter. The meter needs to be able to read at least a 2 or 3 amps for this test to work. Connecting the red wire to the mA input on the multimeter won't work and could damage the meter.
3. Attach a multimeter (set the dial on the multimeter to measure Amps as per multimeter’s instructions) between the negative cable and the negative battery post. Wait a few seconds to several minutes for the car to go into sleep mode - i.e. when you make the contact with the ammeter, the cars computer systems "wake up". After a bit of time they will go back to "sleep".
4. If the ammeter is reading over 25-50 milliamps, something is using too much battery power.
5. Go to the fuse panel(s) and remove fuses, one at a time. Pull the main fuses (higher amp ratings) last. Perform the same steps for relays found in the fuse panel. Sometimes relay contacts can fail to release causing a drain. Be sure to observe the ammeter after pulling each fuse or relay.
6. Watch for the ammeter to drop to acceptable drain. The fuse that reduces the drain is the draw. Consult the owners' manual or service manual to find what circuits are on that fuse.
7. Check each device (circuit) on that fuse. Stop each lamp, heater, etc. to find the drain.
8. Repeat steps 1 & 2 to test your repair. The ammeter will tell you the exact numbers.


BMW Battery Draw Testing
If your Shifter light is on, the car is definitely staying awake.
Your Battery will go down within days. If the light is not on you can have a parasitic draw, while the car is in sleep mode. The only difference, is the second draw is from a module which can’t wake the system (not mission critical), and it will take a lot longer to discharge the battery.

Shifter light NOT on: (battery fully charged)
Find the ground cable on the battery, but do not disconnect. (the cable end connected to the body not the battery, is easier to handle.)
Connect the Positive lead from the “Fluke” to the body of the car (good ground)
Connect the Negative lead to the (brown) ground cable (you can puncture it)
Make sure it’s easy to disconnect the (brown) cable from the body, but don’t
take it off yet.
Open the glove box and remove and disable the switch so the light will not turn on, locate the fuse box.
Start the car and run at idle, turn EVERYTHING on, and activate all the components (sunroof, windows, a/c, lights …..) run 5 min.
turn the car off and remove the key. Open all doors and trunk, and with a screw driver, close the door locks so the system thinks all doors and the trunk is closed.
Now lock the vehicle with the remote.
The “Fluke” must be set up to “A” not “mA” otherwise you will blow the
fuse in the meter. Remove the nut from the ground cable and remove the cable from the stud. You meter will indicate around (300mA).
Let the car go to sleep. (16 min) minimum, if this is not happening start over.
After the sleep mode is on the draw should not be more then 50mA, if it’s more go to the glove box and start puling fuses one by one and check the draw after each one, but do NOT re-install the fuse. Pull the fuse and leave it out.
There are some fuses under the right cover in the trunk. If you pull a fuse and car wakes up start over (next time ignore this fuse). If you pull a fuse and the draw drops to around 50mA, read the label on the fuse, you will know which circuit is faulty.

[andrewwynn]

I have a tool that plugs into a fuse position. It also holds the fuse you just pulled out and will measure the current that is going through that particular fuse. It was under $20 from harbor freight and one of the best tools.


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[StephenVA]

have a part no or picture of that little gem? Can't find it on their website

[talljames]

Great posts. Yes, would love to know who makes that tool. Maybe you can post an image?

[andrewwynn]

https://www.harborfreight.com/30-amp...ter-67724.html

It's unclear if this model is for normal or mini fuses but I'm pretty sure it's the exact one I bought a set it's full size fuse. There is a short wire going between the part that gets plugged in and the display

[StephenVA]

Thanks!

[n25gabe]

Did you work out what was causing your drain?
Bought mine 5 months back. Replaced battery after the 5th jumpstart been fine for months. Now twice in a week battery too week to remote unlock the car.
The only thing that has been different for me was finally managed to pair the phone to the car

[Fifty150hs]

Originally Posted by n25gabe

Did you work out what was causing your drain?
Bought mine 5 months back. Replaced battery after the 5th jumpstart been fine for months. Now twice in a week battery too week to remote unlock the car.
The only thing that has been different for me was finally managed to pair the phone to the car

Unplug your TCU and see if that stops the drain. It's a common cause of parasitic drain.

[andrewwynn]

Most common the FSU aka FSR. They can pull power 24/7 even when not malfunctioning otherwise


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