Author Topic: Sidecar lights with LEDs is puzzling  (Read 890 times)

Offline KiwiGF

  • Last had an A10 in 1976, in 2011 it was time for my 2nd one. It was the project from HELL (but I learned a lot....)
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 1409
  • Karma: 12
Re: Sidecar lights with LEDs is puzzling
« Reply #60 on: 17.12. 2019 20:41 »
So, is that how things will remain?

I suppose so Neil, at least until after the New Year when Paul Goff has all the bulbs I'd like to try back in stock.

Took the outfit out for a run this afternoon for a few miles. Mainly to test it two up, first with my wife as pillion and then back with her in the sidecar. She said she preferred the sidecar but only because she didn't like the feel of the bike going around corners with a sidecar attached, i.e. not leaning into a corner as she's used to it doing.

It’s an annoying problem, and probably not worth pursuing further, however when the lighting circuit is “all led” then it’s possibly that the lighting circuit wiring can “float” around voltage wise, as there is effectively nothing to prevent that happening, even a weak magnetic force near a wire in the lighting circuit could cause a voltage to occur in the lighting circuit and it appears have enough power to operate an LED, putting an incandescent bulb effectively “shorts” the lighting circuit to earth (and prevents it “floating” around) as its resistance is quite low when it’s not getting enough current to get hot.

It’s odd the brake light causes a “stray” voltage in the lighting circuit, I guess the tail and brake wires run close together and so a magnetic field could be causing the issue, but conversely the current (hence magnetic field) is minimal in the brake circuit when it is an LED  *dunno*.

The test for that theory, is to put an incandescent bulb in the brake light (so you get a big current in the stop light wiring) then disconnect the tail light (to ensure the remaining bulbs in lighting circuit are “all LED”) and see if any LEDs light up. If one does, the problem could have two causes!
New Zealand

1956 A10 Golden Flash EA7-168x, CA10 913x, left BSA together for Liverpool, 5th Dec 1955.

1949 B31 rigid “400cc hot rod” (favourite bike)

1949 C11 rigid, but why!!! (cos it was cheap)

1937 B21, missing parts so mission impossible?

1952 Armstrong Siddeley Whitley for rainy days (with wife).

GL1800 Goldwing not sure why, maybe cos it always starts

Offline RogerSB

  • 1960 Golden Flash, Plymouth, Devon, England
  • Resident Legend
  • *****
  • Join Date: Aug 2017
  • Posts: 682
  • Karma: 9
Re: Sidecar lights with LEDs is puzzling
« Reply #61 on: 17.12. 2019 22:24 »
Thanks KiwiGF, much appreciated. As you say it's probably not worth pursuing any further, being nothing drastic. It's more curiosity than anything else now but I will try a different set of sidecar bulbs in the New Year.

My total watts with a 12V 35/35 Quartz Halogen headlight, LED sidecar front light and the 2 LED stop lights all working at the same time (according to my maths) adds up to about 50 watts and with the DVR2 and dynamo belt to help it the 6V E3L should cope well enough. I've noticed the DVR2 cuts in around 40 mph in top.

1960 Golden Flash