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Thread: Strange battery problem showing 12.9v but Fatbob dies

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    Strange battery problem showing 12.9v but Fatbob dies

    Just been out this morning to help my mate who had a problem on the road with his Fatbob, bike would not start after stopping for a coffee, he got jump started first by a good samaritan biker, and rode for a good hour, stopped the bike, same problem, so he called me, lucky I had an extra new battery in the garage, and a XP-1 jumpstarter, so I gets to his bike, I jumpstart it first, leave the jumpstarter on for a few seconds, bike ticks over, take the XP-1 jumpstarter crocodile clips off, bike shuts down, test voltage, battery showing 12.9v, how can this be, so changed out the battery, bike fired up fire, my mate said CIAO lol and he,s riding again, really weird battery shows full but dies, I suppose this is how batteries are, now he owes me many beers.

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    Modern batteries die quickly these days, tell him to get an odyssey or motoblatt unles he feels rich enough for a HD genuine..
    Quote Originally Posted by The Holy Spirit View Post
    I think you may need some therapy poppet.


    Elizabeth.

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    Quote Originally Posted by twizzle View Post
    Modern batteries die quickly these days, tell him to get an odyssey or motoblatt unles he feels rich enough for a HD genuine..
    Man forget the HD batteries they are all made by DEKA anyway, I gave him a brand new Antigravite Lithium 780 CCA that I had in my garage for testing, he is chuffed, them batteries are 500 euros but turn the big twins over like a moped.

    http://www.antigravitybatteries-uk.c...0/action/null/

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    if it is holding 12,9v there is nothing wrong with the battery ... has it been tested after a couple of hours standing?
    paragon

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    Quote Originally Posted by BillN View Post
    if it is holding 12,9v there is nothing wrong with the battery ... has it been tested after a couple of hours standing?
    A mate of mine posted this in the HDFORUM

    Any battery need to produce a high amperage to crank over an engine. Especially in the case of a big v-twin. On batteries this amperage capability is measured in amps and indicated by a 'CCA' figure on the battery itself, it stands for Cold Cranking Amps.

    As a battery gets older this 'CCA' capability diminishes as silt builds up in the battery and the electrolytic plates decay. Whilst the terminal voltage may still indicate that everything is ok the 'CCA' will be down.

    The only way of checking this is by carrying out a load test across the terminals with a load tester. It is basically a big variable resistor that as you reduce the resistive value and effectively short out the battery the amperage will go up. Usually you test a battery for up to 15 seconds at three and a half times the value of it's 'CCA' whilst ensuring that the amperage needle on the tester remains in a green zone on the dial.

    A motorcycle battery with regular use can expect 4-5 years usage before it may require changing. Many find this period is longer before issues finally ensue. Hope this helps!

    When replacing 'Calcium Enriched' batteries are best as they hold a charge better and recover from deep cycling better than normal batteries where the voltage may get very low. Yuasa are a very good make!

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    Quote Originally Posted by Smogbob View Post
    A mate of mine posted this in the HDFORUM

    Any battery need to produce a high amperage to crank over an engine. Especially in the case of a big v-twin. On batteries this amperage capability is measured in amps and indicated by a 'CCA' figure on the battery itself, it stands for Cold Cranking Amps.

    As a battery gets older this 'CCA' capability diminishes as silt builds up in the battery and the electrolytic plates decay. Whilst the terminal voltage may still indicate that everything is ok the 'CCA' will be down.

    The only way of checking this is by carrying out a load test across the terminals with a load tester. It is basically a big variable resistor that as you reduce the resistive value and effectively short out the battery the amperage will go up. Usually you test a battery for up to 15 seconds at three and a half times the value of it's 'CCA' whilst ensuring that the amperage needle on the tester remains in a green zone on the dial.

    A motorcycle battery with regular use can expect 4-5 years usage before it may require changing. Many find this period is longer before issues finally ensue. Hope this helps!

    When replacing 'Calcium Enriched' batteries are best as they hold a charge better and recover from deep cycling better than normal batteries where the voltage may get very low. Yuasa are a very good make!
    many thanks
    paragon

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    Quote Originally Posted by Smogbob View Post
    Just been out this morning to help my mate who had a problem on the road with his Fatbob, bike would not start after stopping for a coffee, he got jump started first by a good samaritan biker, and rode for a good hour, stopped the bike, same problem, so he called me, lucky I had an extra new battery in the garage, and a XP-1 jumpstarter, so I gets to his bike, I jumpstart it first, leave the jumpstarter on for a few seconds, bike ticks over, take the XP-1 jumpstarter crocodile clips off, bike shuts down, test voltage, battery showing 12.9v, how can this be, so changed out the battery, bike fired up fire, my mate said CIAO lol and he,s riding again, really weird battery shows full but dies, I suppose this is how batteries are, now he owes me many beers.
    Try testing the voltage whilst it's under moderate load ie with the ignition on. I suspect it will be much lower.

    Problem sounds to me like the bike isn't charging the battery because if if it was the engine wouldn't have stopped when you removed the jump leads.

    If this is the case his battery is very likely to be ok and just needs charging but the charging problem needs looking into.

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    £500 for a battery.......fuck me...
    Quote Originally Posted by The Holy Spirit View Post
    I think you may need some therapy poppet.


    Elizabeth.

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    Quote Originally Posted by twizzle View Post
    £500 for a battery.......fuck me...
    Yep but man the power is awesome, bike does not struggle at all to turn over, it transforms it into a moped lol.

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    Quote Originally Posted by SteveC10 View Post
    Try testing the voltage whilst it's under moderate load ie with the ignition on. I suspect it will be much lower.

    Problem sounds to me like the bike isn't charging the battery because if if it was the engine wouldn't have stopped when you removed the jump leads.

    If this is the case his battery is very likely to be ok and just needs charging but the charging problem needs looking into.
    Was possibly not the battery, looks like my daft mate drained it to low, he forgot to tell me he filled up left the lights on then had a coffee, 20 minutes later no battery, so basically battery was dead at that moment, but when I got home and put it on the battery tester it showed 12.9v, really weird.

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    Just a quick update to this thread, been steadily charging and then letting it discharge for 2 weeks, it holds 12.9v ok when fully charged, and after about 2 weeks, drops to 11.6v off the bike, then as soon as you crank it over 2 or 3 times it loses all power, so basically a duff battery, will use it for christmas lights.

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    Look at the connection from the battery earth to the back of the engine , both ends of that wire and the shitty crimped connectors.

    Could be either loose or just fucking partially broken like mine was, I made my own cable and soldered the connectors on.

    Fucking crimp fucking connector fucking wankers , how is that even fucking acceptable.


    Sheila.
    Doris doesn't give a fuck...be more like Doris!


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    Quote Originally Posted by The Holy Spirit View Post
    Look at the connection from the battery earth to the back of the engine , both ends of that wire and the shitty crimped connectors.

    Could be either loose or just fucking partially broken like mine was, I made my own cable and soldered the connectors on.

    Fucking crimp fucking connector fucking wankers , how is that even fucking acceptable.


    Sheila.
    I even changed the cables, and looked for as many bad connections until my eyes popped out, new battery fixed it, old one was duff, but cheers for the heads up.

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