Starter or Battery Redux

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

  1. gonzomup

    gonzomup ChainGang Recidivist

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    Roger, I went through something similar to this earlier this year. I didn't take the detailed measurements you're taking, so let's put that aside for now. In my case, the battery seemed to take a charge just fine, registering 12.9V or more immediately after charging. As soon as I touched turned the key on, the fuel pump would prime but I could hear it slowing down in that short cycle and then there wasn't enough juice to crank the starter much, if at all. This was with an Odyssey, about 2 years old, on an approved charger, but the bike had the stock VR and much of my riding is a fairly short commute. (As an aside, I had a reconditioned starter from GS Addict in the bike because my previous one was starting to squeal.)

    I replaced the battery with a new one and all the issues went away. A few weeks after that I upgraded the VR to the higher output Euromotoelectrics version.

    My point is that my battery took what appeared to be a full charge but couldn't maintain it for more than a minute or two. You seem to have a slightly different issue but I wonder if the root cause is similar, i.e., that battery is failing.

    Good luck.
    #41
  2. mouthfulloflake

    mouthfulloflake Not afraid

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    I am pretty sure that a battery starts failing as soon as the electrolyte is put in it right?

    so many cycles at so much depth of discharge and it is simply beyond its chemical means to move electrons.
    #42
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  3. roger 04 rt

    roger 04 rt Long timer

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    That's like what I experienced, on both Oilheads that had had PC680 batteries without a boosted voltage regulator. It seems it's easy to compromise a PC680 (and probably and AGM battery) by undercharging it. And it's easy to be fooled by how well it appears to hold a full charge.
    #43
  4. roger 04 rt

    roger 04 rt Long timer

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    After three discharge/recharge cycles following Odyssey's instructions for how to desulfate the PC680 in order to regain its lost capacity, the GS-911 Wifi was used to collect a start-up voltage data set this morning. In its fastest mode, the GS-911 captures battery voltage and RPM data every 325 mS (about three samples per second), something that can't be done with ordinary shop tools or a regular DVM.

    My R1150GS now starts in under a second after an overnight cool-down period, and the minimum transient voltage is about 10V, up from 8V prior to reconditioning. Battery capacity improved about 20%, increasing to 92%, compared to 78% prior to reconditioning. The ABS no longer logs an error at start-up, compared to several errors before. The steady state cranking voltage (fuel pump relay removed) has improved about a quarter volt, now at about 10.6V compared to 10.3 V before.

    The main lesson learned here (as I did on the RT) is that it's not too hard to damage the PC680 by improperly charging it. Even with a boosted voltage regulator, this battery was sulfated by a non-approved charger, which ran only 6 hours per week, for about 6 months.

    All in all, the results look good, a success. It'll be interesting to see how many more years I get from this battery. In the future, since the PC680 has a low self-discharge rate, I'm thinking that I'll remove the battery for the winter, use no battery maintainer, and recharge it when the bike comes out of storage.

    Below are the before and after charts showing the significantly improved voltage response to starting.

    Screen Shot 2019-08-10 at 9.17.02 AM.png
    Screen Shot 2019-08-10 at 9.17.33 AM.png
    #44
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  5. gonzomup

    gonzomup ChainGang Recidivist

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    Nice work, Roger! I think your discoveries about a non-approved charger working in relatively short cycles is important. I also think your future battery maintenance process is a good best practice, at least until an engineer from Odyssey or with AGM experience chimes in. In other words, probably never.

    :beer
    #45
  6. roger 04 rt

    roger 04 rt Long timer

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    Last week, I started to see the same behavior that I reported at the start of the thread: ABS errors and dips in the starting voltage. The battery seems fine, as it did at the beginning, and the bike cranked well too. I considered trying reconditioning one more time but ran out of energy for the project. I bought and installed a new PC680, which will be a good match with the Vreg mod to 14.6V and my AGM charger.

    After I installed the new battery, I called Odyssey to ask how to identify the manufacturing date. It's the 4 digit code in the white box, on top of the battery. The code is 1111 which means November 2011. I had thought I was working on a 4-5 year old battery that turned out to be nearly 8 years old. For the first 6 years it was charged at a low voltage, so I'd say 8 years is pretty good lifetime.

    [​IMG]

    Here is the plot of starting with the new battery. Note that it dips to about 10.6V for a few hundred milliseconds and then cranks at 11V--much better than the reconditioned results from earlier in the thread. I've added this graph so that others have it as a reference point. Early in the thread you can see my sulfated battery, middle of the thread an 8 year-old reconditioned battery and below, a new PC680.

    Bottom line: the problems were the battery, the starter is fine.

    [​IMG]
    #46
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  7. roger 04 rt

    roger 04 rt Long timer

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    For anyone still interested in this topic, I wanted to update the thread.

    I'll digress for a moment. My 2011 Mercedes has always been a hard starter and I've had 4 batteries in 9 years. The charging system is one of those as needed systems which means it's not always charging the battery. The cranking has been slow for the past 6 years, so I've kept the battery on a tender and that seemed to do the trick. A couple weeks ago the slow starting became no-starting, barely a click. The battery checked out (as it often has in the past). After a little debugging, it was clear the starter was bad and so I replaced it, a real knuckle-buster. It now starts better than new and I've stopped using the tender. I should have known.

    That brings me to my '01 R1150GS. If you had followed the thread, you'll have seen that I reconditioned its PC680 but after a few weeks I replaced it. Fast forward to this summer. The starter still didn't sound great and occasionally the bike was stumbling for a moment just after the first start of the day. Having lived with a bum starter in the car for years, I decided to replace the R1150's starter with no further tests. Fool me once ...

    Beemerboneyard delivered my a new starter the next day and I installed it in about 15 minutes. Not only does it start a bit faster and it reaches a smooth idle directly after starting. The reason is that the Motronic in the R1150--and probably the R1100 too--fiddles with timing to help it recover from a hard start, something I've known for several years. That's what caused the stumble for a moment after starting. My original 19 year-old starter seemed ok but it must've had a high initial draw on the battery, glitching its voltage, glitching the Motronic and causing it to fiddle the timing.

    It would surprise me if there were many other bikes with seemly good starters that would benefit from replacement--something to keep in mind the next time you troubleshoot hard starting.
    #47
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  8. Callisto224

    Callisto224 Long timer Supporter

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    Any thought to cleaning and re-greasing the old starter? You could keep it as a spare.
    #48
  9. roger 04 rt

    roger 04 rt Long timer

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    That's a good question. Last summer I disassembled, cleaned and lubricated the starter. All components of it looked good. It "seemed" to be working fine. I thought about keeping it but decided that 19 years in service was enough and sent it to the scrap pile.
    #49
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