[winston]

2018 urban g/s with 20k miles.

I ride daily and noticed a pattern where every 2 or 3 weeks the starter is sluggish and the battery voltage low. Bike may or may not start.

I get the following sequence on 2 batteries, the original and a replacement, both are AGM, lead-acid, load tested and solid.

I have added some electrical things like running lights, phone charger, and all are disconnected before I run the following sequence.

Morning, bike not started since previous day, fuel pump disconnected, tank up, multimeter gator clamps directly on battery terminals. Terminals clean, connections tight. Voltage reads 12.87. Insert key, turn ignition on, do not touch starter button. Voltage instantly drops to 12.4 as I hear the fuel pump cycle, I hear the exhaust flapper servo cycle, and then silence, in the headlamp the 5 watt running bulb is on, otherwise, nothing on, may be the rear brake LED running light, silence. Voltage continues to drop, 12.3. At this point the starter if fired will feel sluggish or may not turn over at all. On occasion I have seen voltage plummet to 11 and 10.3. Then I turn key to off and remove it. Voltage remains constant at say 12.4 or 12.3 and continues dropping until, at exactly 1 minute from when I turn the key to off, I hear and feel a relay in the flapper servo open, a split second later the main relay opens, and instantly, the voltage jumps a 10th of volt, to say 12.5, and keeps on rising steadily back too 12.7 or 12.8.

I pull the 4 amp fuse and the draw persists. I pull the 10 amp fuse and it stops. So seems to be on the 10amp circuit.

I remove the silencer and observe the servo move the flapper normally. Disconnect the flapper servo and turn the key to on, the draw persists. The main relay tested fine, but I replace it, and the draw persists.

I disconnect the fuel pump on the underside the of the tank, and the draw persists.

I disconnect ABS module. Draw persists.

I run the GS-911 and get no faults, all green. I have run the tests in the scanner including those on the flapper servo, fuel pump, and passed all tests.

Does anyone else find the same 1 minute shutdown sequence?

Does anyone know more about what is going on in this sequence and what might be able to cause a strong silent draw?

I have more experience with marine electric, and in those cases, when I saw similar voltage drop on the battery bank it was something like a bilge pump drawing near 10 amps or maybe a momentary drop by a refridgerator compressor firing.

I suspect this draw is maybe 6-8 amps.. it it was over 10 amps it would blow the 10 amp fuse, but that's never happened.

Thanks for reading.

Any ideas appreciated.

UPDATES:

Today after posting I began to disconnect components one by one. Disconnect, turn on key, watch for voltage drop, turn off key, observe voltage, reconnect. After about 5 cycles of running this sequence, that is to say, disconnecting 5 components, the voltage drop goes down into the 10 volts.. then 1 minute after key off, you hear the clicks of the 2 relays, and within 1 minute the voltage is back up to 12.6 volts. But at this point, I connect the 2amp noco charger and let the battery top off before I continue testing. So far none of the components I disconnect results in any change in the voltage dip. I do not know every component I have disconnected, but I have taken a pic of each and marked the connector with a white grease pencil. I could work to identify each one, but my plan is to wait until I see the voltage drop stop, at which point I will identify.

Here are the components I am familiar with that when disconnected that have no affect on the voltage drop:

• exhaust flapper servo
• fuel pump
• ABS module

Attached is the wiring diagram from my Haynes manual.

 

[winston]

I dont ride off road.. have been inspecting for something like that. With my previous bmw f650's I had a similar problem and the cause was a wire under the tank that was vibrating against the frame and had worn off the plastic coating to the point where it was shorting against the frame. But these bikes were much older. When I look around this bike, everything looks brand new. When I wire up something new, I always wrap the wire in braided or use wire loom. But like I said, anything I have done is disconnected while I am troubleshooting.

 

[winston]

@Tigcraft "I ride daily"

@gene_apodaca I disconnect ABS model, and draw persists. Yes, tank up, volt meter gator clips directly on the battery terminals. Terminals clean and connection tight. Thanks will add this detail to the initial post.

 

[winston]

@rich46 Good question. Both batteries are AGM, that is to say, absorbed glass mat, lead acid. I will add this detail up top.

 

[winston]

@gene_apodaca Thanks. All I do is insert the key and turn on. I do not hit the starter button. The voltage dips as you can hear the fuel pump and the flapper servo cycle.. then voltage keeps dropping. Turn off and remove key, voltage continues to drop until the 1 minute mark when the main relay opens.. then voltage spikes and gradually rises back up. 2018, 20k miles

 

[winston]

@rich46 thanks for the info on the voltage spike. that's interesting.

 

[winston]

@gene_apodaca Yes. Not on the first try, but as I wrote, on the 5th try, the voltagae drops into the 10.x volts.

@Forest yes, 12.8x battery after resting all night is proper. Of course, after riding for a while at 14.5v, the batteries will show 13.x right after cut off.
But regarding your point about cranking, at NO point in this exercise I posted am I cranking, starting, turning over the engine. I insert the key and turn it on. Then turn key off. That's it. I do not hit the starter button.

 

[winston]

@gene_apodaca Thank you, but there is a serious misunderstanding. I am NOT touching the start button. I am NOT engaging the starter.

 

[winston]

@gene_apodaca thank you. I will check tmrw and make sure I've checked the idle actuators and post back. Thanks for the brain power.

 

[winston]

@IanHoots thanks on the alternator diode. As for drawing constantly, this draw does seem to be constant, it only stops when the main relay opens the circuit. I have not disconnected the alternator yet.

Yes when I pull the 10amp fuse, the draw is not there, which is why I am pretty sure the problem is on that circuit. As for starting with the 10amp fuse out, it cant because the starter is on that circuit.

As for the idle actuator drawing that amount of current itself, I dont think so.. but I am disconnecting components one by one just to try an isolate the problem. My guess is that it is a short, bare copper wire on frame, that is causing a draw this strong, that doesn't make any sound. But that guess is mostly because thats what I have seen on my bikes before. I have thought about shooting around with this thermometer gun looking for high temps.. but really hoping that disconnecting something is going to isolate it to a single component and its wiring.

 

[winston]

Thanks a ton for the feedback.

@rich46 thanks for elaborating on the voltage spike.. I find that strange and confusing.. have never seen anything like that. but I wish my bike spiked.
@IanHoots I like the thermal camera idea a lot.. I will study that wiring diagram and try to understand what you are thinking.
@Tigcraft yes I do have a probe tester, but have not used it so far. Hoping to isolate by unplugging.
@Chopper_Bob I do not have an ammeter on hand.. if I unplugging a component stops the draw, I suppose I could insert an ammeter or test light into the circuit there to measure.
@Lelc2 good idea about the heated grips. I did use them a few times lately, but this problem started in hot weather. As for length of rides, typically 20-30 minutes to. 1 hour.
@Chris. when I first started to troubleshoot, I would put the meter on the bike as soon as I parked.. and measure it on the hour until I went to bed, and then check in the am. Did this for days. I never saw any kind of loss. Always dropped very slowly to the resting point around 12.8. Then I started testing with the key on and found the draw. Since I have had both batteries load tested and because this testing process taps the battery, I put it on the 2amp charger after running the tests. As I added up top yesterday, by the 5th test, which is simply turning the key on, leaving it for a few seconds, not touching the starter button, and turning key off, the voltage was dipping into the 10 volts. Within 1 minute of being off, it was back up to 12.7, but at that point, I put it on the 2amp noco and let it top off, within less than an hour, its on float charge.

 

[winston]

If anyone is inclined to humor me and try this test I have been running on YOUR bike, I would be interested to know the outcome:

I have the tank up and the fuel pump disconnected so I can clip directly to the battery, but that said, I get the same results if I jus take the seat off and clip to the positive bolt at where the seat meets the tank and the negative bolt on the underside of the right head.

1. With the bike cold, preferably over night for the first test, I see the voltage.
2. I insert the key and, watching the voltmeter, turn to on- I do NOT touch starter button.
3. Watch the gauges cycle, hear the fuel pump and flapper servo (if you still have it) cycle, then wait 5-10 seconds after all is quiet, watching the meter.
4. Watching the meter, turn the key to off, and pull it out to make sure. At exactly 1 minute after turning key off, hear/feel servo and main relay open, voltage jumps, and then slowly rises back to resting voltage, within about 1 minute.
5. Repeat 5x, not waiting overnight between each test, just a few minutes, long enough for the battery to rise back up resting voltage of say 12.7 to 12.9

What I am interested in knowing, is the range of the voltage dip. On the first test, mine starts at 12.8 and dips to 12.4 or 12.3. By the 5th test, mine starts at 12.7 and dips to 10.5 volts.

 

[winston]

@gene_apodaca thanks. I actually just confirmed that as someone else had asked, when I pull the 10amp fuse and turn the key on, nothing happens and there is no change in voltage, so I am with you on that one. As for pulling other fuses, the only other one I know of is the 4amp fuse.. and pulling that doesn't not affect the voltage drop. The bmw pocket user manual only mentions these 2 fuses.. are there more?

 

[winston]

Interesting problem you got there.... Now call me crazy, but isn't everything on these bikes canbus?
Instead of blown fuses we get canbus to shut down circuits. Have you tried checking for logged events?

Yes, thx, using GS-911. No faults. Passed all tests.

 

[winston]

Winston, Being a simple guy I'd first take my test light and go through all the accessories and switches (side-stand,horn,turn-signals) to see if anything is hot that should not be with the key off. I'd then pull apart the switches so I can get to the small circuit boards and do the similar test. I have had the same issue with a Honda Goldwing and a Kawi touring bike and found the trouble there; the result of a wire being chafed by electronics without proper install by the owner. Something is drawing electrons from somewhere so I always start with the most easy to repair. If the trouble is there you replace or repair a wire or switch takes less time and will most probably cost the least. If the trouble is within the more complex components then go with God and good fortune.

With things such as wiring troubles remember the old adage "when you hear the sounds of hoof beats look first for horses not Zebras " I only say this because your trouble seems rather simple in that your battery is not crashing, there's no smoke and the wrenched thing starts from time to time. Now it may be some demon in the ECU but at least hope not.
I have had one faze of the starter motor go bad from time to time so when the starter is in one spot the thing will not start or is hard to start; put the motorbike in gear and bump the thing a bit against the Bendix and try again and off you go. I don't even know if this is even relevant in modern motorbikes and one would think you'd be getting some proper error message on the clocks if this was the trouble but it's a thought..

Thx, I have not gotten into the switches yet. One by one, with the tank up, I disconnected 10 components, and cycled the key on/off watching voltage. The voltage always dropped regardless. Then I tried @IanHoots idea and got a thermal imager. Low and behold, the idle actuator lit up like a candle. I had already tested them individually, but I thought, perhaps they must both be disconnected at the same time. Nope. Same voltage drop. But very cool idea and good to see that I could not find any hot spots.

Just above my index finger you see the idle actuator, a bit blurry in the background, but that's what is showing warm in the lcd screen. For anyone who wonders, above that and going over the air intake is the black flexible conduit, the wire loom, which is carrying all must custom wiring for running lights, horn relay, and phone charger, all of which are individually slid into braided cable sleeve. All my previous electrical problems, with other bikes, have been due to wire coating being rubbed off and touching the frame, usually combined the the fact that a wire was not properly routed or secured, so this time around, I took no chances. Everything is then zip tied, or sometimes while working out the routing, I will temporarily use velcro cable ties, then once the design is set, secured with zip ties. All my work goes into the healtech tb-usb2, which is connected to the battery thru the positive bar just behind the tank, and a rock solid ground. This heal teach unit only turns on power to my peripherals once the bike is running and rpm's are above idling. Main goal being, nothing I wire up can pull power until the alternator is cranking. The other goal, is that in troubleshooting times like these, to disconnect all my work, I simply disconnect the healtech unit. And another benefit is that you dont get a stack of eye connectors piling up on your positive post.

 

[winston]

Hi Winston,
when you are performing the test , do you recall how long the ignition / 10 a fuse is live total time in minutes to reach 10 v from 12.87, ,
It is possible to measure the actual current drawn by measuring the voltage across the fuse,
there is a calculation matrix depending on type of fuse, i use an amp hound when checking muliple fuse boxes to save time,
out of interest what other additional electrics are added and how are they powered/ controlled
have they been in use when the bike intermittently fails,
what journey times frequency in the days before the non start,
what battery voltage is displayed when the non start occurs without cranking ,
apologies for the questions, trying to help,
Forest

Thanks, as for live time, each test is about 1 minute 15 seconds max. 15 seconds key on, probly even less, because as soon as I see the voltage drop, I know the draw is there, and then the cpu or something on the bike opens the main relay at exactly 1 minute from key off. Thanks for math tip, I figured there must be tables for determining amp draw from voltage drop, AWG, and time, but never knew for sure. Thanks for the amp hound tip, looking into that. I have always found the ammeter function on multimeters to be fiddly, esp burning out the 10a fuse in them. Just mentioned additional electronics in previous post, 40 watt running lights, horn, phone charger. Did not mention the hyper-lite LED turn signals and brakes, but given the 700+ watt alternator, hard to find trouble in the list. Problem started before I used the heated grips. Daily trips 30m+, never measured any daily voltage drop with bike off, measuring in the hour, then following morning.. never seen a noticeable drop. Appears to be limited to when bike is on. As for measuring voltage before a no can crank event. Since I started measuring voltage, I haven't had one. that said, when I did have those events, in less than 1 hour on the 2amp noco charger, the battery is at float charge... and always starts then.

 

[winston]

I measured my 2018 UGS so you have some references, note my bike hasn't been run for about week and is not on a trickle charger.

Key Off 0.0A 12.8v
Key On 2.9A 12.4v
After 3mins 2.8A 12.3v
Key Off 2.1A 12.4v
After 60sec 0.0A 12.6v

I can repeat this several times with very little voltage loss... my battery gets back up 12.8v after a few minutes of no load.

It does seem like you have you have something drawing substantial current from the battery when the key is on, if it is getting down to 10v. You need to actually measure the current to know what is really happening.

Page 7.40 of the Haynes manual should guide you to what components are effected when the 10A fuse is pulled. You can rule out the starter motor and alternator as they are connected to the battery even when the key is off.

Thanks a ton for doing this test and posting voltage PLUS amps! Extremely helpful. I am going to get something to measure amps, perhaps the amp hound. Thanks for the manual tip, not sure if I've seen that. And thanks for the info about the alternator and starter motor remaining connected even after key off. I thought the main relay disconnected them when it opened.

 

[winston]

Thanks everyone who read and esp all who posted. I basically gave up after 10 disconnects and the heat imager. All that was left under the tank to disconnect was zipped and taped bundles.. and I considered that if I tore them all apart, what would be the chances that I didn't find the problem, and instead created another, and decided those were decent chances.. and that since the problem was not critical, I would just set it aside and go ride. Which I did with no problems. Now circling back, some good ideas here on how to isolate the problem have inspired me to carry on and tool up for the next problem that comes around.