Due to some issues with my dynamo I am also checking the possibility of installing batteries powered lights.
While checking in a shop, together with the usual LED stuff, I noticed a front light having the indication of "4 lux" on the package. See below info taken from manufacturer web site.
The AXA Scope is a standard LED battery headlight with a light output of 4 lux and 2 bright LED's, very suitable for children's or city bukes.
The integrated retro reflector makes sure you are better visible to oncoming traffic.
LIGHT BEAM: 15 meters ‘to see’ 1000 meters ‘to be seen’
Is that enough, poor or what? I usually cycle on roads with public illumination on, but sometimes I also ride across parks where the only light is that cast from stars and Moon.
Out of curiosity after the detailed answer received, I decided to try the LED above mentioned (the shop allows returning within 30 days) in real conditions. So I took it home and tried it early this morning in my dark garden from a standing position (I didn't want to go through the hassle of mounting it on the bike).
- It casts a decently broad lobe of light, therefore I didn't have to scan around to figure out what I had ahead of me
- indeed it enabled me to see until the backyard door, which is roughly 15 meters from where I stood.
Conclusions: it seems better than the LED torch I am using now as a workaround and comparable with the dynamo powered light I used to have, but I think I will opt for a new dynamo. It will at least saves my money on the long run: if I have to trust their claim on 50 hours autonomy I should swap batteries once a month.