Originally Posted by
avole
The Brompton front light is mounted too low, turns off when you stop and the dynamo increases resistance when you pedal. At night I have both sets of lights on, and it is the USB that lights up the road, though it is on more for visibility, as we have street lights everywhere here, until 23:00h anyway.
Do not forget: You have an outdated halogen front-light on your Brompton that has been exchanged on new Bromtons aready six years ago. The
BuM IQ X has standlight, lightsensor and daylight-lightening, near-field light and offers 100 Lux of bright white LED light. The picture of the light fieled from BuM is typically on the very optimistic side of life but still gives an idea:
Your's offers ~15 Lux of yellow halogen light and has no other features. So it is obviously not possible to judge on an IQ X if you only know your halogen light and it is close to impossible not to offer better light than your current one, even with a candle...
The light-filed-picture of an 10 Lux halogen-light from BuM is again more than just optimistic (from my experience the Brompton's factory halogen-lamp is far worse than that) but offers a bit of a relative comparison to what the IQ X offers:
(both pictures from
here)
Dynamowise you have the low end shimano dynamo (the lowest end dynamo that shimano offers) that is heavy and has a lot of drag in on- as well als in off-mode. The SON has no noticable drag in neither mode and is a lot lighter and bullet proof (but expensive). The SP8 and SP9 as possbile alternatives are in between.
With a IQ X or an
Edelux2 nothing is left to desired lightwise, even with the low mounting point on the Brompton. If you wish you can mount both on the bars as well, then offering an even better field of light but possibly leading to the same issues with the fold that battery light on the bars habe. Of the two I clearly prefer the Edelux2 because of longer warranty, less blinding and better build quality. My IQ X failed after only 10 months while my Edelux 1 + 2 lamps have been running strong already for years. Plus the IQ X is very (!) sensive for correct adjustment otherwise it will blind other traffic very badly.