2016 RTW electric draw

[topophilia]

Seeking the collective wisdom of this group.

Back-round; 2016 R1200RTW with 42000 miles. recent battery which tests good. Problem exists with a different battery as well.

Problem; Phantom electric draw when off. All tests as follows are repeatable and documented.

1) All peripherals are disconnected so that the bike is in the "as delivered" condition.
2) Start bike with ammeter connected between the battery negative post and negative cable.
3) Turn off bike and amp draw runs approximately 3.3 amps and as low as 2.6 amps.
4) After about 60 seconds, a relay behind the diagnostic port clicks, the exhaust flapper releases and amp draw drops to around .57 amps.
5) After about two minutes, amp draw decreases to .1 amps and remains there.
6) I have systematically disconnected every connection plug I can find while watching amp draw but have not found the phantom draw.

At this rate, the battery is depleted at the rate of about 2.4 Amp Hours per day and is insufficient to start in about a week.

All tests have been run many many times and repeat with the same results. All of these tests have ALSO BEEN RUN on an identical bike equipped exactly the same and manufactured just 33 serial numbers apart.
The results are nearly identical except that the control bikes resting amp draw drops to 0.0 amps after about two minutes.

Any ideas? I appreciate any thoughts.
Bob

 

[Omega Man]

Well presented question
My first thought would be if there was a GPS or NAV left in the “sleep” position.
Let us know how you make out.
OM

 

[topophilia]

Good thought, but alas the GPS sits on the work bench along with all the tupperware.

At least I am getting to clean all the nooks and crannies one can't get to normally.

 

[oldcamper]

I would try unplugging the rectifier. I do not know where it is, though.

 

[topophilia]

Good suggestion. I too do not know it's location. Will investigate.
Thanks, Bob

Found it!

Just for clarification. Found the rectifier, not the problem!

 

[TRJeff]

Check the accessory BMW plug in for corrosion, water gets in from rain and washing the bike

 

[cap]

100 milliamperes sounds like some background draw like a clock or a USB charging port. Reminds me of a test question in a college course on electronics… the difference between Norton and Thevenin equivalent circuits.

Cap

 

[explorer]

Is it possible that the light in the top-box (if fitted) is still illuminated? You could disconnect the top-box with the round connector under the rear seat. (At least that is where it is on the 2020 RT.)

Good luck -
Larry

 

[pglaves]

Is it possible that the light in the top-box (if fitted) is still illuminated? You could disconnect the top-box with the round connector under the rear seat. (At least that is where it is on the 2020 RT.)

Good luck -
Larry

Easy test: open the box and see if the bulb is warm. Warning: It could be really hot. I once firmly grabbed a car trunk light bulb to see if it was hot. I wont do that again.

 

[Omega Man]

Could also use a smartphone in video mode to see if the light is functioning properly.
OM

 

[pglaves]

Could also use a smartphone in video mode to see if the light is functioning properly.
OM

That is a better idea. Technology trumps blisters.

 

[52184]

1) All peripherals are disconnected so that the bike is in the "as delivered" condition.
6) I have systematically disconnected every connection plug I can find while watching amp draw but have not found the phantom draw.

How have any peripherals been tied into the bike’s electrical system? Direct-wired? Through low-draw relays? Through CanBus bypass devices? If the latter two have been used, have they been disconnected during testing? Unplugging a peripheral but leaving a relay or bypass in place can result in a micro draw, especially if the device is not wired correctly or functioning correctly.

This sounds like either a shutdown message is not making its way through the CanBus system or is not being recognized by a device. That, or a relay or bypass device being tapped into the system and being faulty or tapped in such a way that it’s interfering with a shutdown message. I don’t know if connecting the bike to the dealer diagnostic system would reveal which circuit/device is still drawing power, but that might be worth a shot.

Good luck,
DeVern

 

[topophilia]

Thank you all for the suggestions.

ALL added peripherals are de wired so as to remove potential draws from relays etc. When I say de wired, I do mean both positive and negative.
I have no top case.
I removed the wires from the auxiliary power port to eliminate that.
I have even removed the wiring for the radio module and have physically removed and de wired the Motronic module.
I have not yet removed the LED headlight and it's associated starter and resistor but will do that next. Unlikely as it has been functioning without issue for the past 3 years and the "test bike" is also equipped with the same LED headlight.

Will keep looking till I exhaust all avenues, my patience or find the culprit so please keep brainstorming with me.

Thank you,
Bob

 

[bobs_one]

I hate to say it (as its an expensive repair) but it's possible one or more of the diodes in the alternator have failed. You should be able to get to the output leads of the alternator and test for this.

 

[pglaves]

I hate to say it (as its an expensive repair) but it's possible one or more of the diodes in the alternator have failed. You should be able to get to the output leads of the alternator and test for this.

This is a distinct possibility. But such ought to be detectable by testing the peak output voltage at mid-RPM. A failed diode should result in only two of the three AC legs producing output - at least that is what happened on our F800S. It wouldn't go above 12.9 volts running at 3K RPM or so. The electrical engineers can now weigh in, if I am wrong, which is a possibility.

 

[56982]

I really don't know how can bus works , but is there any way to start pulling fuses while the meter is on and see if it drops to zero .

 

[r0ckrat]

I really don't know how can bus works , but is there any way to start pulling fuses while the meter is on and see if it drops to zero .

There should be a main 50 amp fuse and one blade-type fuse under the seat. Along the right side of the ECU box. Holder looks like:

https://shop.maxbmw.com/fiche/DiagramsMid/B0009370.png?v=09082020

 

[topophilia]

Well, I don't know how exactly to say this, but today while doing probably my hundredth cycle of testing the @$#$%^& thing started to work correctly!

That is to say that where previously the lowest draw I would get is .1 amps or 100 milliamps after all the brains and drains timed themselves out, it started to drop to 0.0 amps. This is the same as my "test" bike.

This I repeated a dozen or more cycles with no change in results. The darn thing fixed itself???

I am going to leave all the Tupperware off since it is still a bit cold for riding and continue to test it a few times a day. Failing any more failures, I guess I will just go back to riding and keeping a close eye on my resting voltage
until the problem either returns or I forget about the issue.

Sure wish I knew what changed. The only thing I did differently since all your input that I hadn't done before was wiggle the connections to the rectifier. I would have disconnected it completely but it is a bear to get to.

By the way, my charging voltage is 14.4 so I think my alternator diodes are intact.

I still hope that someone reading this thread will have an AH HA moment and let us all know that there is a reason and a solution.

If the issue rears it's ugly head again be sure that I will resurrect this thread and see if there are answers.

Thank you again, this forum rocks!

Bob

 

[jandhumphreyme]

Glad things are sorted out, interesting delimma. Such a low amperage draw is hard to diagnose. I know some OEM auto manufactures have issued bulletins on modules comming out of sleep mode causing slight current draw, reprogramming solved some of those issues.

 

[topophilia]

And just like that It's back.

As promised, I have been rechecking a few times a day and all good. Now the phantom draw is back exactly as before.

SIGH