Fun Stuff > CHATTER

Bickering about bicycles, now with occasional tips about motorised vehicles

<< < (193/203) > >>

ev4n:

--- Quote from: The Seldom Killer on 15 Oct 2014, 03:49 ---There's no shame in investing in a decent set of lights.

--- End quote ---

True.  The problem is the large overlap of dark and snow in Canada.

Still, I'll probably pull the trigger on something like this over the winter, to be ready for spring.  Daytime highs in the single digits are looming.

Akima:

--- Quote from: bhtooefr on 15 Oct 2014, 04:18 ---I just wish I could put a dynamo on my trike, rather than have to recharge that thing.
--- End quote ---
Dynamo lights (actually, modern systems use an alternator, not a dynamo) are elegant, and the better ones impose little drag. The problem with them, in my opinion, is that they are simply not bright enough for riding at night in city traffic where they have to compete with so many, much brighter, lights in an environment designed around motor-vehicles.

Most good quality hub generators (Schmidt, Shimano etc.) are built to meet German legal requirements and have a rated output at 15kph of 0.5A @ 6V, or 3W. Even if you install a battery-powered rear light, so you can devote that entire output to your headlamp, it is not very much. Good systems have very well designed optics to make the best possible use of the light, but it is just not adequate for night riding in a totally car-centric city in my opinion.

I think the 12V Busch-Muller Dymotec S12 is still available, and that has a more respectable 6W output, but it is a "bottle" style generator that relies on a drive-wheel pressed against the side of your bike's rear tyre. These tend to suffer from slippage in wet weather, and impose wear on your sidewall, but are an option to consider. The 6W output is still not that great, however.

I have a 12V 5A/Hr rechargeable battery on my bike, driving a 25W halogen headlamp and a 9-LED non-flashing rear light. The current drain is such that the battery can run the system for about 1.5 hours (my current commute ride is roughly 30 minutes, my longest ever was just under an hour). I went for a sealed lead-acid battery rather than anything more exotic because they are relatively inexpensive, and good-quality "float" battery-chargers are available from car/motorbike accessory places at low cost so you can easily afford to have one at home and one at work if needed. More modern, lighter weight battery types (NiCd, NiMH, LiIon etc.) and their chargers are much more expensive. A general rule with bike lighting is: "Light, Cheap, Powerful: Chose two".

If I were thinking about doing the Paris-Brest-Paris randonnée, or something else that required riding all night, I would install a generator lighting system, but for city night-commuting I think the money (for good generator systems are not cheap) is much better spent on a powerful rechargeable battery system.

bhtooefr:
Mind you, my cycle commuting is mostly on cycle infrastructure or through business driveways, which does help with the whole having to compete against cars thing.

I could always get new steering knuckles made for my trike to take the available single-sided hub (the SON XS-M), mind you... and then on a tadpole trike, there's the possibility of running two of them for extra power.

The other thing that can help increase power output is reducing wheel size while using a hub set up for a large wheel, although the SON XS is already set up for ~20" wheels.

Akima:
Boosting the output of your generator by fitting it in a smaller wheel than it was designed for, or simply riding faster than the stately 15kph assumed by German law, raises problems of bulb-matching. Many generator lighting systems have voltage-control electronics to prevent excess voltage blowing the bulb. If you bypass that and install a bulb that can run at higher voltage, you need to make sure the mounting can stand up to the increased heating. And even if you double the output, it is still not high compared to a battery system.

I have seen clever designs for home-brewed electronic regulators that divert excess generator output to charge batteries, and then draw on the batteries to prevent the headlamp dimming when riding slowly, uphill for example, but I don't think anything like that is available on the retail market. If I went for a generator system, I would consider building one.

bhtooefr:
Although, if you're designing the light driver electronics specifically for the higher power available, complete with a LED module and all that's optimized for it... (It might be worth looking at the pedelec version of the Saferide 80, for that, actually...)

And, actually, the B&M IQ2 Luxos U stores excess energy to do short bursts of 90 lux operation (default is 70 lux). Of course, that doesn't say anything about how many lumens it is...

Navigation

[0] Message Index

[#] Next page

[*] Previous page