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Higher wattage alternator

  • Wideglider
    Wideglider
    6 years ago
    Have a '96 WG, a few extra accessories fitted that drag battery voltage down a little. Voltage stays up nicely with minimal loading (13.8V). Anyone have experience with a higher wattage alternator?
  • gidgi
    gidgi
    6 years ago
    any one correct me if wrong but your whole bikes electrical system is designed for a certain amount of amps.... fuses , resistors , capacitors, wiring , globes ect buy increasing watts .{Volts x amps = watts } would likely create more problems . my aging brain is fusing a little more each day but this assumption is based on  doing electronics certificate at TAFE years ago if I got it wrong pls chip in
  • Wideglider
    Wideglider
    6 years ago
    You're right gidgi, P=V x I. But I will not be drawing any more current than rated with a higher capacity alternator - it's the voltage part of the equation that I want to keep up to what it should be. Lamps, heaters, radios, fans etc will draw only what they need - they will not draw more just because a higher capacity alternator is fitted. I am just wanting to increase the available 'capacity' of the alternator so as to reduce the voltage drop I'm seeing now when it is loaded up. It's all just about keeping the voltage up where it should be. My voltage regulator is fine as it keeps voltage up at around 13.8 volts when not too loaded up.
    The voltage drop is happening inside the alternator. A higher rated wattage alternator would just have slightly larger diameter windings to decrease the resistance in them, this results in less voltage drop (V=IxR). Every accessory has its own correctly rated fuse installed & the current drawn in each of these circuits will remain the same. 
  • Wideglider
    Wideglider
    6 years ago
    Thanks loopie.
    Just had a look at Rick's but nothing for my bike.
    I see HD offers a high ouput alternator/regulator kit (54 amps) for tourer models but still searching for something for '96 WG.
  • gidgi
    gidgi
    6 years ago
    Quoting Wideglider on 15 Jun 2018 12:42 AM

    You're right gidgi, P=V x I. But I will not be drawing any more current than rated with a higher capacity alternator - it's the voltage part of the equation that I want to keep up to what it should be. Lamps, heaters, radios, fans etc will draw only what they need - they will not draw more just because a higher capacity alternator is fitted. I am just wanting to increase the available 'capacity' of the alternator so as to reduce the voltage drop I'm seeing now when it is loaded up. It's all just about keeping the voltage up where it should be. My voltage regulator is fine as it keeps voltage up at around 13.8 volts when not too loaded up.

    The voltage drop is happening inside the alternator. A higher rated wattage alternator would just have slightly larger diameter windings to decrease the resistance in them, this results in less voltage drop (V=IxR). Every accessory has its own correctly rated fuse installed & the current drawn in each of these circuits will remain the same. 

    sort of makes sense but if you got a 12 v battery, well yeah they will read around 13 sumfinc volts mark in good nic , & yeah that will drop when acc & lights on but the alt will continue to keep the charge up to it , when bike is running all acc & lights & stuff come from the alternating current not the battery, same as if ya car has a flat battery & you use another good battery to start ,then remove said battery when car is going, providing your alternator is working car should keep running... please note Im no expert just got me thinking cheers
  • WideglidingNZ
    WideglidingNZ
    6 years ago
    No expert myself but would a higher capacity battery help?
  • gidgi
    gidgi
    6 years ago
    Quoting WideglidingNZ on 15 Jun 2018 01:52 AM

    No expert myself but would a higher capacity battery help?

     just sumfin I pulled of the net  to show 3 different capacity batteries for your 96 wide glide https://www.batterystuff.com/batteries/motorcycle/harley-davidson/1996/1340cc-fxdfxst-seriesdyna/    maybe worth a try if you have a lower CCA (cold cranking amps ) battery note the  150 cca    320 cca or 500 cca  in the link , hope it works check what you have good luck 
  • Wideglider
    Wideglider
    6 years ago
    Quoting WideglidingNZ on 15 Jun 2018 01:52 AM

    No expert myself but would a higher capacity battery help?

    Quoting gidgi on 15 Jun 2018 04:03 AM

     just sumfin I pulled of the net  to show 3 different capacity batteries for your 96 wide glide https://www.batterystuff.com/batteries/motorcycle/harley-davidson/1996/1340cc-fxdfxst-seriesdyna/    maybe worth a try if you have a lower CCA (cold cranking amps ) battery note the  150 cca    320 cca or 500 cca  in the link , hope it works check what you have good luck 

    Thanks WGNZ & gidgi,
    I have a larger battery, a larger CCA battery is primarily used for just that - high cranking current for higher compression engines to supply a higher current for short bursts without voltage dropping too low.
    With my issue with extra accessories, a larger battery would maybe help for a few minutes in keeping voltage up but then the battery will start discharging, because again my alternator/regulator will not keep up - it's purely a case of supply & demand, taking more out than we are putting in (you don't get anything for free). This is why HD & others offer high output alternator/regulator charging components (just can't seem to find to suit my bike yet).
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