Results 1 to 9 of 9

Thread: Electrical Query on 48 Panhead

  1. #1

    Default Electrical Query on 48 Panhead

    Hi Guys

    Is the wiring loom (recently replaced) capable of handling; short term use of all spotlights (2 at 35w), headlight (35w), tail light (5w), brake light (15w) etc etc, with a 6 volt battery (22ah)? This would be drawing 125w with 6 volts and so 20+ amps? Should I be using LED bulbs?

    I have installed an 8-0-8 amp ammeter (which is obviously too small). I can increase the range by using a shunt resistor but can't remember how to calculate the correct shunt resistance - any electrical engineers around? Would it be 0.05 ohm and 150watt??

    Thanks

    Greg

  2. #2
    Join Date
    Apr 2010
    Posts
    1,110

    Default

    They had all of that + fender light,sidecar light & taillight without ever knowing what an LED bulb is

  3. #3
    Join Date
    Nov 2018
    Location
    Reno NV
    Posts
    167

    Default

    Greg,
    A 0.5 ohm 72 W shunt resistor would give you a 20 a range on your ammeter.
    However I think the 20 amps would be too much for your wiring.

    I would expect the spotlights are wired through a relay and powered directly through a fused supply from the battery.

    I am sure this has been done before and someone with experience will hopefully confirm this.

    Cheers,
    Mick

  4. #4
    Join Date
    Oct 2011
    Posts
    474

    Default

    The ammeter shows the difference between the load and generator output,so you may be ok.
    Tom

  5. #5
    Join Date
    Nov 2018
    Location
    Reno NV
    Posts
    167

    Default

    Tom,
    Until the motor stops with everything turned on.

  6. #6

    Default

    Not sure on a 48 but on my 47 the headlights and spotlights were either-or, not both simultaneously.

  7. #7
    Join Date
    Oct 2011
    Posts
    474

    Default

    Yeah ,theres that.The other worst case is charging a dead battery.
    British car friends who want to keep thier original Lucas 30A gauges with an alternator conversion shunt the ammeter with a piece of 14 gauge wire.Readings are about halved ,but the numbers arent considered as important as which side of the 0 the needle is on and keeping the original gauge.
    Tom

  8. #8
    Join Date
    Aug 2004
    Location
    Beautiful Northern New Mexico
    Posts
    2,737

    Default

    H-D always wired spotlights to low beam side of a 21/35W bulb. They were intended as passing lights, not running lights so draw was intermittent. So was brake light. The battery covers the momentary drop, continuous use will drain the system. The fender light and taillight also functioned as parking lamps in those states where they were required, but leaving them on longer than a short period is a dead battery.
    Robbie Knight Amca #2736

  9. #9

    Default

    thanks guys, terrific!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •