Finally after seven years, revision 2.0 of my Quick-And-Dirty Bicycle Lighting System...
Step 1: Parts List
1x U5 fisheye motorcycle headlight/spotlight
4x LED truck/trailer sidemarker
1x LED trailer tail/stop light
1x LED three-terminal flasher
2x roller microswitch
1x scooter headlight/turn/horn switch
2x 6-10-terminal euro-terminal strip
6-10' multiconductor cable
Dacron fishing line
Aluminum strip stock
Step 2: Brake Switches
Mount lever switches front and rear and link to brakes so switch closes when brake operates. Wire switches in parallel. I used switches with rollers and tied braided dacron fish line to the roller and to the brake cable core at the brake cantilevers (with a 'taught-line hitch' at one end to allow adjustment) - connections were made to normally-closed contacts and switches oriented so switch is held open until brake movement releases microswitch lever.
Step 3: Brake/Tail Light
For this version I used a LED Trailer brake/tail light.
Step 4: Turnsignal/headlight Switch
I used a scooter light switch with turn, headlight, and horn functions.
Step 5: Turn Signals
Turn signal lights may be either amber led side markers (truck/trailer side markers can be found in most any auto parts store) or motorcycle turn signal lights.
Step 6: Flasher
Many but not all "LED" 3-terminal flashers will work:
CF13JL02 type (at least the ones marked FCR:LED instead of "for LED") do NOT
MF-5 (6V-12V, 0.1W-100W) Motorcycle Flasher has been verified to work.
Jiye SG252B (12V 135W) verified to work and produces an audible click from relay and has pilot led confirming operation.
Step 7: Headlight
Headlight is a "U5 fish-eye" motorcycle light typically advertised as "135W", 3000 lumen (Chinese math: TWO will have the illuminating power of a 135W non-halogen incandescent based on the theoretical 10x efficiency of LED vs tungsten + the narrower beamwidth of a projector lens light, the actual box will say 18W 2200 lumen in one place and 9-12W 1200 lumen in another and "lighting power 30W" - measured power consumption is around 5-6W) Note: there are similar "U1", and "U2" lights on eBay/Amazon that are smaller (may claim 5W by are actually 2-3W) and some "U7" lights that are basically identical - the "right" ones will be either a plastic "bullet" with an aluminum shroud or an aluminum "bullet" with q claimed power of "30W" or "135W" (and may include an Angel eye/Devil eye feature)
Step 8: Battery
Battery is a "12V" lithium camcorder/cctv power bank - common ratings range from 1,900 - 20,000 mAh (exaggerated in proportion to claimed capacity as per usual with Chinese L-ion batteries...)
Step 9: Connecting It All Together
I used euro-terminal type barrier terminals for interconnections and fabricated mounts for the turn signals out of scrap aluminum strips.
Step 10: Horn
I had a cheap battery-operated Chinese bicycle horn on hand that had failed (rainwater got in and corroded the switch and battery contacts although the circuit board was waterproofed...) and fitted a small (120 mAh) LiPo and charging circuit (12k resistor) and a 4-conductor cord (USB cord with a broken plug...) to feed 12v for charging, and extend the connections from the former push button to the horn connections on the lighting switch. This allows me to blip the horn button with my thumb to alert pedestrians that I'm approaching from the rear, or give gashole motorists a blast of the horns siren-like warble when they act like a dozy pillock...