Warm start fail puzzle

[Peter Room]

I can't get my head around this and would appreciate suggestions.

 

2014 R1200RT wethead, 74,000km, battery 6 months old, oil level good.

Once or twice per week for the past 3 months the same sequence:

Cold start OK.  Air about 17deg.C, engine temperature OK. Stop for coffee after about 100km. After 30 minutes, sidestand up, clutch in, ignition switch on, wait for speedo & tacho to zero, press start, engine fails to rotate & computer looses user settings as though ECU thinks battery lacks charge, but... 
Ignition off, wait 10 seconds, ignition on, wait for needles to zero, clutch in, press start, engine starts, re-enter settings, start moving, dash shows 14.2 volts when cruising, ride another 200 to 400km, switch off at home, attach smart charger which takes only minutes to reach 'float' mode.
12 hours after removed smart charger, dash shows 12.4 volts and cold engine starts first go. So, the alternator seems to be working, the battery is holding charge, and I would expect battery/starting problems to be worse when the battery and oil are cold, not warm.

 
If something is reducing current to the starter motor at first attempt at warm start, why does she start on the second attempt after only a few seconds?
Are the ECU, starter relay, or selenoid sensitive to temperature? Slowing my getaways and re-entering settings are minor hassles but is this a warning of a more serious problem developing?

[dirtrider]

59 minutes ago, Peter Room said:

I can't get my head around this and would appreciate suggestions.

 

2014 R1200RT wethead, 74,000km, battery 6 months old, oil level good.

Once or twice per week for the past 3 months the same sequence:

Cold start OK.  Air about 17deg.C, engine temperature OK. Stop for coffee after about 100km. After 30 minutes, sidestand up, clutch in, ignition switch on, wait for speedo & tacho to zero, press start, engine fails to rotate & computer looses user settings as though ECU thinks battery lacks charge, but... 
Ignition off, wait 10 seconds, ignition on, wait for needles to zero, clutch in, press start, engine starts, re-enter settings, start moving, dash shows 14.2 volts when cruising, ride another 200 to 400km, switch off at home, attach smart charger which takes only minutes to reach 'float' mode.
12 hours after removed smart charger, dash shows 12.4 volts and cold engine starts first go. So, the alternator seems to be working, the battery is holding charge, and I would expect battery/starting problems to be worse when the battery and oil are cold, not warm.

 
If something is reducing current to the starter motor at first attempt at warm start, why does she start on the second attempt after only a few seconds?
Are the ECU, starter relay, or selenoid sensitive to temperature? Slowing my getaways and re-entering settings are minor hassles but is this a warning of a more serious problem developing?

 

Evening Peter Room

 

You need to get a voltmeter ON THE BATTERY after the bikes sits overnight & during the problem happening.

 

I don't know how accurate that dash shows but 12.4 volts on a modern AGM battery is fairly low (that is not nearly fully charged)  

 

You should probably also get your battery load tested as it sort of (from info given/ ie, computer looses user settings) points to a battery issue (or a battery connection issue). So, also check your battery cable to battery  post connections.

 

If the battery part checks out as being OK then possibly look into a hot-soak starter drag, or a hot soak battery cable resistance increase (do a voltage drop test  across both positive & negative battery cables).

 

It's kind of a tradeoff, cold engine/cold oil does crank with a bit more difficulty but that is offset by hot battery, hot starter, & hot battery cables decreasing available cranking energy.

 

You can also try jumping from another bike when the problem shows up, if that helps cranking then look into a battery low capacity problem.  

 

What kind of smart charger are you using? If using an older charger not rated for the new AGM batteries then it's output & charging algorithms  might not be correct for your AGM battery so through continued usage it can significantly lower the battery's cranking amp output capacity. (if this is the case then the battery can usually be saved with a precise rundown &  recovery sequence using a proper Amp/voltage output battery charger).

[Peter Room]

Many thanks Dirtrider - lots for me to check & I'll post results when I have them all.

[Peter Room]

Update

 

I rode about 350km yesterday with 3 stops and there were no problems starting so I could not check voltage when the problem happened..

 

Battery voltage after left not attached to charger overnight was 13.02v at the terminals according to my multimeter.  The -ve post connection was not as tight as I like and just might have caused the problem, though why only when warm and not on a second attempt when warm I don't understand. I made sure both connections were good when I put the battery back.

 

My charger is a BMW one with "CE" on the front and A-907 on the back. It's user manual is dated 09/04 and it says "It can be used to charge BMW motor bike lead acid and maintenance-free lead batteries (gel or AGM) with capacities from 2.5 to 25 Ah."   The battery is a BMW/Exide AGM 12v/C10: 14Ah manufactured 17/1/2018.  Maybe my 15-year old charger is not suitable for this battery, but I have not seen any BMW advisories about this.

 

If the problem recurs I'll get the battery load tested and check with BMW about suitability of their 15-year old charger for current AGM batteries.

[Skywagon]

Peter....follow DR...however will let you know my bike did the same thing.  Changed the battery and all is well.  I know your battery is fairly new, but it could still be bad.

[dirtrider]

8 hours ago, Peter Room said:

 

My charger is a BMW one with "CE" on the front and A-907 on the back. It's user manual is dated 09/04 and it says "It can be used to charge BMW motor bike lead acid and maintenance-free lead batteries (gel or AGM) with capacities from 2.5 to 25 Ah."   The battery is a BMW/Exide AGM 12v/C10: 14Ah manufactured 17/1/2018.  Maybe my 15-year old charger is not suitable for this battery, but I have not seen any BMW advisories about this.

 

If the problem recurs I'll get the battery load tested and check with BMW about suitability of their 15-year old charger for current AGM batteries.

 

Morning   Peter Room

 

Does your charger manual actually say (gel or AGM) or is that something that you assumed from the maintenance-free lead batteries call out? (BMW didn't have much for AGM batteries back in 09/04). BMW did have gel & those take a different charging voltage &  different charging stages than the AGM.  

 

That somewhat loose (-) battery cable could easily have caused your problem as that type of connection can not work at first try but arc enough to make contact & work the 2nd try.   

 

That 13.02 is just a tad high but not much & probably OK as just overnight probably wasn't quite long enough  to completely flash off the surface charge.

 

The thing is; if your present battery charger has lowered your battery's available cranking amps  that might not show up in just a simple overnight battery voltage test. It SHOULD show up in a battery load test or in a hot engine voltage test while cranking.