LED Tail Lamp for Bullet

Thought of posting this an year ago when I did and installed this circuit on my bike, but then forgot. I’m a living example for procrastination.

This is one arrangement I thought of when I started using extra headlamps on my bike that drain battery very fast. One solution I thought of was to cut the power to other bulbs that are frequently in use- tail lamp and break light. I think a tale lamp bulb rating is 10W and 21W for break light.

I replaced the bulb with an LED setup same as that in most of the newer vehicles (not on any Royal Enfield though). This one is not as exclusive as those come from the factory, but it serves the purpose and when the tail lamp cover is fixed we don’t see the setup inside but the light. This alteration has been done on a TB tail lamp that has more than enough space inside to add a circuit board. Same setup is possible inside a regular tail lamp too, but need to reshape the circuit board a bit which is not a big deal.

Components:
Line Circuit board - 1
LEDs (bright and focused type. Ordinary ones are useless) - 8
Resistors (4K7 Ohm) - 2
Wires (about 6 inches in length) - 3 pieces
Bulb that suits the socket of the tale lamp, glass and filament removed - 1

There are two different circuits for the tail lamp and the break lamp. A set of 4 LEDs are used for each. The LEDs are connected in parallel with the resistor in series to them. Ground is common for both circuits. Wires are soldered directly to the terminals pop out from the broken bulb, which are insulated with sleeves or insulation tape.
Two small aluminum clamps are soldered to the board and is fitted on the base tightening screws.

Tips
I have used red colored LEDs for the break lamps and are pointed straight (The top row in the pic). Two of the tail lamp LEDs are connected straight and are red in color. The other two are pointed down and are white in color to illuminate the number plate.

Gain
Instead of 10W/21W the new set up draws only a fraction of a mW. (I haven’t calculated the correct value though)

PS: The circuit can be improved by designing a bigger and shaped circuit board and by adding more LEDs to improve brightness.

This is a new design I have tried on my new bike. The setup has more LEDs. The illumination is not very impressive. It would have been better with reflectors.