Harley starter current

Discussion in 'General Electronics Chat' started by #12, Feb 28, 2016.

  1. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    Does anybody know the starter current for a Harley Davidson motorcycle?
    I think I should put a fuse in, but it's not a, "for sure" thing.
     
  2. tindel

    Active Member

    Sep 16, 2012
    568
    193
    Wow - #12 has a question.
     
    NoelSof, cmartinez and #12 like this.
  3. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    How thick are the cables on the starter motor?
     
    #12 likes this.
  4. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    It would help if you could post a schematic....:D Just kidding.

    Why do you think you need a fuse??
     
    #12 likes this.
  5. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    The typical battery for a Harley is rated at 200 to 270 CCA. (Same battery size as a 1500 Honda Goldwing.)
     
    #12 likes this.
  6. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,128
    266
    No fuse, never seen a fuse used in that situation.

    Just jump off and run when the wire starts smoking.
     
    #12 likes this.
  7. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    I agree with @Sensacell . I have put a lot of miles on street and touring motorcycles and have never seen a starter fuse.
     
    #12 likes this.
  8. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    Looks like about #4 AWG
    Sometimes, when the battery is low, the starter solenoid fails to release and the starter motor cranks until the battery is dead. The solenoid being mechanically stuck, you have to kill the main supply to stop the failure mode. Still haven't decided...big old switch on the battery or a fuse.o_O
    Starter solenoid out of a Ford with a panic button.o_O
     
  9. tindel

    Active Member

    Sep 16, 2012
    568
    193
    Sounds to me the solenoid is not working properly.
     
  10. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    #4 AWG Can carry around 70-80A. So it should be somewhere around those numbers when under heavy load.

    Clamp multimeter would do you good.
     
    Last edited: Feb 28, 2016
  11. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    That is true. Unfortunately, replacing the solenoid only gets me the same solenoid.
    This isn't a problem on one motorcycle, it's a design flaw in the solenoids.
    This cable isn't designed as a continuous current wire. It's designed for x number of volts of loss at y number of amps. Standard building codes do not apply to this design. The length being about 14 inches.
     
  12. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    and the battery in my car is rated for 450 CCA, but that never happens.
     
  13. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    If typical starter motor has 1200-1400W at 12-13V that means that current draw is ≈110A.
     
    #12 likes this.
  14. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    4023 ft/ohm in a #4 AWG cable.
    248 uohms/ft
    Theoretically 290 micro-ohms.
    3448 amps per volt.
    No help from the math.:(

    0.037 volts per 110 amps.

    Then again, most of you know it's difficult to get under 1/10th ohm in the connections.
     
    Last edited: Feb 28, 2016
  15. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    ......and how would a fuse solve this problem??
     
    #12 likes this.
  16. tcmtech

    Well-Known Member

    Nov 4, 2013
    2,034
    1,651
    I'm going with the ~100 amp estimate as well. It's about what my 22 HP B&S engine on my lawn mower draws.

    A two cylinder Harley and two cylinder B&S are about the same right? :confused:
     
    #12 likes this.
  17. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    Still haven't decided. Maybe a long duration current compared to the usual 1-2 seconds of cranking.
     
  18. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    LOLZ.:D
    I don't think they are similar, but 110 amps seems like the right area.
     
    Last edited: Feb 28, 2016
  19. #12

    Thread Starter Expert

    Nov 30, 2010
    16,277
    6,788
    Gotta go for a couple of hours. Back at 11 pm, my time.

    I suppose I could get a DC ampmeter, but I'm too cheap to buy one for one job.
     
    Last edited: Feb 28, 2016
  20. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    Harley's always start the first time......... o_O A fuse would just contribute to a different kind of problem.

    Why do the solenoids stick? That is the problem you want to solve.
     
Loading...