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Does the hot/red wire coming from the battery also recharge it?

Discussion in 'The Garage' started by Xander Stephens, Sep 19, 2019.

  1. Xander Stephens

    Xander Stephens XS360CafeRacer

    6
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    Utah
    I bought a new battery for my bike and a few questions came to mind:


    Is the hot or red wire coming from the battery, also the wire that the battery is recharged through?

    And if it is, how is it possible for the battery to be outputting energy, and receiving energy through the same wire?

    Thanks for the help
     
  2. Charge comes up from stator down by the sprocket in 3 wires. Hooks in to the regulator and rectifier and then up to battery
     
  3. Xander Stephens

    Xander Stephens XS360CafeRacer

    6
    0
    1
    Utah
    But how does it go from the rectifier to the battery? There’s only 2 wires coming from the battery.
     
  4. BBS360

    BBS360 XS400 Guru Top Contributor

    Current can flow in either direction on those wires. It's one system with two possible current/voltage sources.
    If the alternator output exceeds the battery charge level current flows to the battery to charge it.
    If the battery is fully charged the voltage regulator drops alternator output and current flows from the battery.
     
    buztabuzt likes this.
  5. Gra900

    Gra900 XS400 Enthusiast

    So I’ve just rewired the charging circuit, and the red from the rectifier is connected to the red from main fuse to main switch like the wiring diagram says (400SE, 4G5) This means the the battery is always connected via the rectifier to ground even when key is out. I’m getting a 0.01 amp leakagefrom my battery +ve to earth now. That doesn’t seem right, I would think the rectifier red should go to the brown after the main switch. Any thoughts
     
  6. XSLeo

    XSLeo XS400 Junkie

    Yes the red wire stays connected to the battery positive at all times.
    The rectifier is a set of 6 diodes that convert the AC output of the alternator to DC the bike can use.
    Diodes are a one way valve for electricity. The way the diodes are set up battery current won't flow from the battery to ground.
    There may be a very small current flow through the rectifier, but it is so small as not to worry about. It would take months to drain a battery. The battery would drain as fast unhooked.
    With a bit of searching you can find a more complete explanation of how this works. Your repair manual is a good place to start.
    Online is another.
    Leo
     
  7. Gra900

    Gra900 XS400 Enthusiast

    Hi Leo,
    Cool thanks, I just remeasured the current drain and it’s 0.01mA I’m losing, with a 12 Ah battery it will last for 37 years.
     
  8. BBS360

    BBS360 XS400 Guru Top Contributor

    .01mA is probably far less than the resolution of your meter.
    It might not be leaking at all.
     

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