Water bottle battery for bicycle lights

1. Parts:

• Sanyo 20700 x 6

• 8A PCB and M/F Molex connectors

• 16AWG stranded wire

• DC extension cord

2. Weld taps on cells: for 8.4V output battery pack, three cells are bundled in parallel, and serially connected to another bundle of three parallel cells.

3. At the core, I put a 20mm carbon tube, which helps the pack maintain hexagonal shape. A PCB will be placed within the carbon.

4. Lezyne container will be used for packaging.

5. Plastic sheets for insulation of the battery pack - I picked up the plastic sheet from a recycle bin.

6. Connect PCB and connectors

7. Wrapping

8. Packaging in the Lezyne container.

9. Done. Left is the finished work and the right is the original battery pack.

12750mAh, 461g

7800mAh, 336g

Charging

Final test

LED headlight - Radio noise filter

After installing a pair of retrofit LED headlight bulbs, I started getting noise when listening FM radio using my care stereo. The RF noise is from the driver circuits of the LED bulbs, which use high frequency switching similar to the RF radio frequency.

So I decided to design a passive filter, which I found very effective to block the noise. Now, after installing the filters, the radio noise is completely gone.

Capacitor-less AC LED driver

Current waveforms

Let there be extra Lumens!

Lithonia flush-mount LED fixture Mod

Since the original Lithonia LED fixture is not bright enough to illuminate my living room, I have added extra LED strips (4-foot long in total) along with two 12W LED driver. The drivers are manufactured by Illuminous, and 'Triac-dimmable'. Pretty cool, huh? They also worked greatly with my Lutron wall dimmer. On the back of the fixture, i.e., on the wall-side, I had to add extra heatsinks to dissipate extra heat. Anyhow, extra Lumens do not come for free. Thanks to the heatsinks, I managed to suppress the fixture temperature under 71 dec Celsius at the steady state (measured after two-hours continuous run).

- Nominal brightness
  - Original: 1600lm
  - Mod: 4000lm
- Wattage
  - Original: 23.0W
  - Mod: 50.8W
- PF
  - Original: 0.94
  - Mod: 0.89