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Starter or Battery Redux

Discussion in 'GS Boxers' started by roger 04 rt, Aug 4, 2019.

  1. LAFS

    LAFS Long timer

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    "A healthy 12 volt motorcycle battery should maintain a range from 9.5 - 10.5 volts under the load for a good 30 seconds straight. If the battery begins to hold and then steadily drops in voltage, there is a problem."
    This from batterystuff.com
    #21
  2. roger 04 rt

    roger 04 rt Long timer

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    I’ve cleaned and lubed the starter except I’m wondering whether the shaft under the bendix drive should lubricated and with what. I don’t want lube flung at the clutch.
    #22
  3. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    Dry and clean, or a VERY light layer of grease. I've done it both ways. Wet collects brake dust faster.
    #23
  4. roger 04 rt

    roger 04 rt Long timer

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    Yesterday I downloaded the latest GS-911 software for PC and updated the GS-911 Wifi firmware. Unfortunately the realtime value sampling rate has dropped from 350 mS to about 3 seconds! I've contacted Tech Support but they're in South Africa so I'm unable to log effectively at the moment. Does anyone know how to go back a revision?

    There are some things I know. The cranking voltage after the starter clean & lube, with the fuel pump relay pulled, is still about 10.5 volts, same as before. A friend (GS Addict) with the same bike and a very well maintained PC680 measured his cranking voltage at 11.4 volts for 12 seconds. Also, when I went to record realtime values with the GS-911, twice it dropped off. I'm going to go out on a limb and say that the connectivity drop-off is most likely due to the battery voltage dipping when I press the starter--meaning I still have a problem.

    Just as a recap, the bike turns over very well and will crank for a long time. I just have this transient voltage dip that makes the bike take a couple more revolutions of the engine to start.

    The next step will be to try reconditioning the battery and see what improvements that yields.
    #24
  5. rdbonds

    rdbonds Breaker of Things

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    roger 04 rt - Good thing you checked the starter...sounds like it was not the source of the problem, but that it needed some attention anyway.

    With regard to the battery, I agree that it's likely the cause, given the voltage drop and other electronic symptoms. I'm curious though, if it's several years old and clearly degraded, why not simply move to replacing it? Short of having an emotional attachment to it, why bother attempting to recondition it for a few more months of service? It's borrowed time and you won't trust it anyway...

    Just a thought...
    #25
  6. roger 04 rt

    roger 04 rt Long timer

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    That’s a very good question. The battery still turns the engine over fine. It’s not that the battery is worn out (if that’s the cause) it’s just developed some sulfation internally.

    The simple answer is that I want to identify the root cause. The last time I went through it, I got seven more years from the battery and when I sold the bike it was still fine.

    The first discharge cycle will tell me a lot.
    #26
  7. Coma

    Coma Long timer Supporter

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    Battery equalization can yield some impressive results. Sulphur can affect a single cell and can be desulphured with a constant voltage. I’ve equalized 7 year old batteries that tested as new afterward.
    #27
  8. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    10.5 Volts during cranking is in the good range. GSAddict's result is partly from a very good battery, and he has a newish starter (IIRC).
    #28
  9. roger 04 rt

    roger 04 rt Long timer

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    I believe you're right that he does have a newish starter.

    My first discharge cycle yielded about 13 amp-hours out of 16 amp-hours for a new battery. That is about 80% of new capacity. Odyssey considers this a failed/worn-out battery. I’m recharging it now. It will be interesting to see if the next discharge cycle is improved. If it is only sulfated it may improve. Odyssey says to run up to 5 discharge cycles.
    #29
  10. mouthfulloflake

    mouthfulloflake Not afraid

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    I went thru this recently

    A good new Deka battery was like $80 shipped to me

    The bike spins over faster than ever, I am quite over trying to milk 5 years out of a battery

    I pushed my dr650 half of a mile last fall trying to get it started and home on a 3 year old battery

    Never again

    The GS does roll start easily in good weather though , but really, I want a good strong battery in all of my bikes
    #30
  11. roger 04 rt

    roger 04 rt Long timer

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    Hi MFOL, I may end up replacing the battery, but mine has "seemed fine" until the ABS started acting up. And even then the bike started in just a couple rotations of the engine.

    My '04RT battery was only one year old when I sulfated it during development of lambda-shifting with the LC-1, by using the BT Jr. to keep it topped up. After reconditioning it per Odyssey instructions I got its capacity into the high 90s and ran with it for another 7-8 years. Then it took me 4-5 discharge cycles to get the capacity back and get the bike to the point where it started on the first rotation.

    When the first half second of cranking is with a battery voltage of about 8V, the injectors barely spray fuel and the spark is weak, that's why it takes the extra second to start. With the battery voltage up in the 10s or 11s, there's a good spark and plenty of fuel, and hence faster starting.

    Most Oilheads that have AGM batteries but a stock Alternator/Voltage Regulator will have some amount of sulfate built up on the plates and will have degraded starting performance to some degree.

    I'm real curious to see where this battery ends up--revived or worn-out.

    BTW, I stuck the all the discharge data points into a spreadsheet this morning and got 13.4 Ah or 84%. The battery took 4 hours and 30 minutes to fully discharge using a 4 ohm 50W resistor (3 amp nominal discharge rate.
    #31
  12. roger 04 rt

    roger 04 rt Long timer

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    One quick update:

    The GS-911 is not logging slowly as I reported (in haste). What is happening is that after i cleaned and lubed the starter (coincidentally I guess) the battery glitch was large enough when I pressed the starter button that communication between the Motronic and GS-911 stopped for 3-4 seconds--both are powered by the bikes battery voltage. I suspect the Motronic but can't prove that yet. I guess I was just lucky to catch the transient on my very first realtime log.

    Because of the 3-4 seconds of lost communication it doesn't record the glitch ... but since communication is lost (and that rarely happens) I feel confident saying that there was still a sizable voltage dip after servicing the starter.

    I'm just about to wrap up the second discharge cycle and it looks like the battery capacity will have increased to 14.8 Ah, up from about 13.8 Ah the first time. Progress.
    #32
  13. roger 04 rt

    roger 04 rt Long timer

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    I just finished the second discharge. It took 5 hours and 20 minutes and yielded 15.3 Ah, which is around 95% capacity.

    There was another change too after the first discharge cycle, when I attached my programmable power supply (set at 14.8V) the current started at 4.5 amps, and climbed to 5.5 amps in the first hour. The battery then charged overnight. After the second discharge cycle, when the power supply was attached, the charging current was about 9.5 amps right away and stayed there for a couple minutes and is now slowing coming down. It seems a good sign based on Odysseys data which says to charge it correctly you need to charge with a minimum 6 amp supply.

    The battery will now recharge for the rest of the day.
    #33
  14. mouthfulloflake

    mouthfulloflake Not afraid

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    So even with the modded voltage regulator your bike is not charging the battery correctly?
    #34
  15. roger 04 rt

    roger 04 rt Long timer

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    Good question, complicated answer. I bought the bike a couple years ago and the battery had been in the bike for a while. But here's the whole history since then:

    —June 2017: ‘01 GS purchased stock 14V VR, reconditioned the PC680 per Odyssey instructions.

    —Summer 2017: Used approved charger to top up PC680 after every ride (a pain).

    —Winter 2017: For 7 months, the PC680 was on an unapproved trickle charger for 6 hours, once a week.

    —Summer 2018: Noticed after taking the bike out of storage that it was starting slightly slower than the prior year, assumed it was storage/gasoline. Modified the VR with a diode to boost charging voltage, and occasionally used an approved charger. Rode all summer with the boosted VR but ignored the fact it was taking a full second or second and a half to start.

    —Winter 2018: Used an approved charger

    Looking back at that sequence I’m beginning to think that my Winter 2017 unapproved trickle charger sulfated the PC680 somewhat since it was during the summer of 2018 when I first noticed the slower starting (and did nothing about it till this year).

    So the VR mod would have been fine if I didn't "cook" the battery back in the Winter of 2017. It appears that once sulfated you have to fully discharge and recharge to correct it.
    #35
  16. roger 04 rt

    roger 04 rt Long timer

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    Interesting side development ...

    I've been unable to get the GS-911 to record values fast enough since I first discharged the battery. Hexcode processed a trouble ticket for me but said they couldn't duplicate it. Further study of the data showed that every time I pressed the start button, there was a 3 second delay from the Motronic so I couldn't see the transient voltage dip during the first second.

    This morning I realized why that might be happening. I have been discharging the battery while installed in the bike. The voltage has dipped to 10V twice, and the first time it reached 9.54V for several minutes before I got back to check. That was enough to reset the Motronic apparently, and I never reregistered the throttle (key on, rotate the throttle twice, key off). Apparently, without the key on/rotate/key off after disconnecting the battery, the Motronic does some housekeeping every time the starter button is pressed and it keeps doing that until the throttle is reregistered.

    After resetting the Motronic and reregistering the throttle, the GS-911 now logs at full speed, even during the startup transient.

    On the third start of the day (while I figured out the GS-911 problem) the 300 mS transient voltage was 9.54 volts. Much better than the 8.05V recorded at the start of this project. However, since it was the third start of the day, I don't think we can rely on the 9.54V data point.

    The battery is now discharging for the third time, and I will reregister the throttle before my next test!
    #36
    JimVonBaden likes this.
  17. rdbonds

    rdbonds Breaker of Things

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    Kudos to you, Roger. You're a very patient person, and teaching us (at least teaching me) about how to recover a seemingly failed battery. I must admit, I'd have replaced it with a $100 battery, gone for a ride and never given it a second thought. :) I suppose if you're not in a hurry and interested in the journey of learning about it, it's a neat process to go through.
    #37
  18. roger 04 rt

    roger 04 rt Long timer

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    My main objective isn't to save the battery. What I'm hoping to prove to myself is: is the battery weak and causing the slightly slower starting, or is the starter drawing too much current at the moment the starter button is pressed?

    If I fully recondition the battery and then I still get slower starting, I'll have to look further or just replace the battery and hope for a win. If I do that and still get slow starting then I'll spring for a starter.
    #38
  19. roger 04 rt

    roger 04 rt Long timer

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    In my discharge methodology I hadn’t take the resistance of my cables and the SAE connector into account. I went back to the shop and measured it with a 3amp current and got a surprisingly high 0.33 ohms. I also spotted two small errors in my spreadsheet.

    Here are are the revised numbers:

    1st discharge: 12.4 Ah, 78% capacity, 4 hours 30 minutes
    2nd discharge: 14.8 Ah, 92% capacity, 5 hours 20 minutes

    I'm running a third discharge now.
    #39
  20. roger 04 rt

    roger 04 rt Long timer

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    1st discharge: 12.4 Ah, 78% capacity, 4 hours 30 minutes
    2nd discharge: 14.8 Ah, 92% capacity, 5:20
    3rd discharge: 14.8 Ah, 92% capacity, 5:20

    The third discharge cycle was just the same as the second. I may have reached maximum reconditioning. However, the battery has been sustaining a 10 amp recharge rate (maximum of my power supply) for half an hour so maybe there's some further improvement coming.

    At 92% capacity, there's still more life in this battery according to Odyssey, who says to replace at 80%.

    After the bike is fully recharged and has sat overnight, I'll run a cold start test with the GS-911 and see what the battery drop is like.
    #40