Bike run on alternator once started

Discussion in 'Softail Models' started by Java, Dec 25, 2009.

  1. Java

    Java New Member

    Merry Christmas!
    I ride a 05 Deluxe and the battery went dead. I am going to replace the battery and check the charging system with a meter. The question is--shouldn't a bike once started be able to run on the alternator?
  2. jaceddie

    jaceddie Junior Member

    No, the way I understand it is it runs off the battery. The stator, etc. is just used to keep the battery charged.
  3. Breeze3at

    Breeze3at Well-Known Member

    Everything on the bike "runs" on 12 vdc from the battery. The alternator puts out alternating current, which the regulator/rectifier converts to direct current to go to the battery. That's why you can't run with a shorted out battery, it has to be able to accept some charge from the regulator. Sometimes a battery will never charge enough to start the bike, but it will convert enough to run it.
  4. Hoople

    Hoople Account Removed

    Don't do it. It would be the Kiss of Death.
  5. poohbear

    poohbear Active Member

    In the old days, when there were Generators, once the bike was started you didn't need the battery, generators made there own juice. Now with all the 'New Age' stuff and the fact the lights are always on you need everything and it all has to be in good shape. Alternator, Batteries are all part of a loop, think of it like a water hose, if it is good shape great but if it has leaks not so good.

    NEWHD74FAN Experienced Member Retired Moderators

    Poohbear's analogy is right on...your bike is essentially a battery system with alternator/regulator setup to surface charge the battery, power the EFI, ECM etc. and any excess voltage is "dumped" by the regulator as excess heat. Wonder what would happen if the battery is not there? You really do not want to find out, as the battery also acts to store and dampen the high voltage transient spikes that the alternator/diodes are putting out, while the alternator tries to put out as much power as possible to compensate for the lack of 250A or more of CCA and reserve power the battery supplies. Without the battery, the stator/regulator parts will overheat, the insulating varnish melts, windings short to ground and turn into cooked spagetti. This is not something you want to have happen...