The Bontrager Ion 200 RT /Flare RT light set is one of the best daytime running light for bicycles. It is not only very lightweight but also highly visible at long distance. The light set is of a particularly high quality. For my bicycle on solar energy, the Maxun One, I made daytime running lights myself and that is why I was curious how the Bontrager works. I cut the Bontrager Ion 200 apart to find out at what's inside.
Cars are an increasing danger to cyclists. This is because the motorist is distracted by operating the abundant of electronics in the car, such as navigation, smartphone, etc. A car sometimes looks like an airplane cockpit, with the difference that in an airplane there is a co-pilot to operate everything.
Bontrager Ion 200 RT holder 3D CAD model
I designed a holder in Freecad, you can customize it to your liking. See here at GitHub.
You can cut open the case with a knife and glue it back up later, for example with a glue gun.
Lens reflector collimator
For bicycle lighting, you cannot properly use a bare LED without a lens because:
The light surface of a LED is too small
The beam angle is too large, usually 125 degrees, see Fig4.
That is why a lens, reflector and a collimator is used. The lens and reflector focus the light on a surface of 17 mm. The collimator consists of a bead surface of the lens and creates a parallel light beam, see Fig5.
The Bontrager can be wireless controlled by a Garmin navigation device by ANT+. This is conceptually similar to 2.4 GHz Bluetooth low energy, but it is specialized for sensors.
Apparently, the device can be controlled by Serial Wire Debug via the USB connector. Note that the Bontrager connections of the USB are completely different from the standard.
Synchronous step-down converter
The converter operates at a frequency of 1.4 MHz, see Fig3. However, the LED current is not constant as expected, but it has a sawtooth shape with a much lower frequency, namely 1.6kHz, see Fig1. I wonder why this is made so.
LED current and luminous flux
The LED current can be calculated as follow: UR1 = 50mV average, see Fig1. I led = 50mV / 0,3Ohm = 170mA With a Cree Xlamp XTEAWT-00-0000-000000HE4, the luminous flux may be about 170/350 * 150lm = 70lm.
Flash mode
In flash mode there are 3 pulses of 50ms and 2 pulses of 100ms, the period is 1,3s. See Fig2. The total on time = 100+100+3x50 = 350ms
Battery life during sleep mode
The microcontroller and the two crystals are running during power off. The sleep current is between 90 and 150uA, the average is about 120uA. The battery life during power off = 420mAh / 120uA = 3500h = about 20 weeks
Battery life at flash mode
The average LED current = 0,35/1,3 * 167mA = 45mA The theoretical battery life = 420mAh / 45mA = 9 hours In practice it is approximately 5 hours.
Battery replacement
If the battery is worn out, you can replace it with a new one: 3,7V, 420mAH
