Alternator output voltage?

wild.coast Jul 9, 2018

  1. wild.coast

    wild.coast Test Drive

    Installing a winch, so figured I'd test my battery and alternator.

    Battery is reading 12.6v when the truck is off, which I think is perfect
    When the engine is running (at idle) I'm reading 13.99v - I thought a healthy alternator should be between 14.2 and 14.5v? Does the mean the alternator is starting to go?

    This is on a gen1 (2004). I know some cars have variable output alternators, does the 1st gen Xterra?
  2. thecoalition

    thecoalition Call me Daddy Super Moderator Supporting Member

    Richmond, Va
  3. Muadeeb

    Muadeeb Bastard Admin from Hell Admin

    13.6 is normal vehicle voltage, so any alternator voltage above that is acceptable. I wouldn't fret a 14v alternator voltage as long as it can keep your battery charged.
  4. 12° North Industries

    12° North Industries Bought an X Site Sponsor

    Near The Pointy End, NV
    A very small percentage of that is needed to keep the battery charged anyway. The Alternator primarily runs the vehicle itself whilst the battery runs mostly accessories. Stick to regular batteries or AGM batteries for the winch setup.. Keep 2ndary batteries like deep cycle types used for ancillary or aux features for those. A winch will kill off a deep cycle battery rather quick as its not meant for discharging quickly or high amperage.

    I would however suggest the addition of adding whats called Anderson Plugs inline for power leading them/the connection near the grill area for serviceability and or future use; say such as a quick disconnect of the winch and providing a service port to run a set of custom battery jumper cables. ;)

    i.g. -
  5. Riz98

    Riz98 Test Drive

    lemoore, ca
    If your concerned about your alternator voltage after installing the winch you could upgrade to a 99-03 alternator from a Nissan Quest with the 2 sliding doors. That alternator is rated at 125 amps vs the xterra at 80 amps. You just have to swap the pulleys and after that its all the same. This is on my list of upgrades also.

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