Halogen Lights / Dynamo Help

[Ian W]

Hi!

Not strictly retro but I'm sure you don't mind helping out

My misses bike has a set of halogens and a dynamo fitted and I can't figure out how to get it to work? :|

I have the dynamo setup so it rotates when the bike is ridden but there is no on/off switch for the lights which is because you just move the dynamo when it's off right?

Anyway, basically the lights don't seem to work! I tried connecting them to a regular battery to test them but that didn't seem to work either? I am doing something wrong? What is the easiest way to test them? Any idea how much riding is required to get them to kick in?

She only does just over a mile from the train station to home but it's getting dark now and she needs lights, maybe regular batter ones would be a better option?

Thanks

 

[Titiritero]

Re:

Your question is not very "retro" so I'll reply assuming the risk moderators will move your post (you could always argue that now that most bike lights are LED, halogen lights are "retro"! ;-))

Btw, your assumption is correct. In bottle-dynamo designs, the "switch" is just using or removing the dynamo. Hub-dynamo lights have a switch at the back of the front light.

First, the obvious, make sure the halogen bulb is not burnt out! (a replacement costs 1 eur max).

The reasons why your light is not working could be many, so I will list some of the possibilities:
-usually you should have 2 contact points on the light (earth and actual electrical current). In good quality dynamos you would have also 2 contact points. Make sure you connect like with like (most cables are black, with one having a small white stripe so you can differentiate them at both ends).
-if your dynamo is the older type with only one contact, you can do the whole connection with one single cable, but it will be more instable. Better to connect the earth cable from your light to some steel part of the frame (usually the dynamo holding bolt, or to the frame once a bit of paint is scratched to ensure contact).
-if both dynamo and light have only one contact point, then run only one cable, but as said your connection won't be very stable in the long term (you might have to touch the frame, if steel, from time to time with a key or similar to "discharge" it).

Other factors to consider:
-ensure the rolling wheel of the dynamo is rotating in the right direction. Some are designed to be installed on the left side of the wheel (front, or right side at the rear wheel) or the other way around
-make sure the spring of the dynamo is strong enough to force rotation against your tire (without causing too much drag)
-make sure your tire has a dynamo strip on the side (some rugged area) so the dynamo has an area to attach to and doesn't slip.
-make sure when the dynamo is at work, it is approximately in a radial line from the hub for best results.

Also, be aware that usually front lights need 2.4W and rear lights just 0.6W, while dynamo output is normally 3W. That means that is ok but not great to run only a front light, but not ok to run only a rear dynamo light as in a few days you would burn the bulb (it also happens with LEDs , they just hold up a little bit longer).

For city use, I always prefer dynamo over battery lights. Once properly installed you forget about them, they never run out of battery in the worst moment, and you don't need to remember removing them (usual reason for getting battery lights stolen) or bringing them back from home/work. When I go out at night, I hate to carry the lights in my pocket all the time...

 

[Ian W]

That's fantastic Thanks for the info

 

[hamster]

If you have a single cable setup, the best thing is to provide a decent earth return (as said by Titiritero, these are usually the cause of problems). A cable linkage between the lamp bracket and the dynamo bracket will solve this: typically 30cm of one half of a mains cable with a cleaned metal-to-metal contact at each end will improve things no end.

 

[02gf74]

Re:

Why bother when you can buy led emitter lamps that actually light up where you going?

Is it worth risking death and injury for the sake of £15

(And charge the batterh at work for free)

 

[Titiritero]

Re:

Is it worth risking death and injury for the sake of £15

It's obvious you have not used dynamo operated lights lately.

Cheap battery lights, even if LED, are just to be seen. If you really want to illuminate your way, you need to start spending 40 EUR or more just for a decent front light, and for that money alone you can already have a full set of dynamo lights.

I have both types, and battery lights are best for occasional use, i.e on your mtb or road bike for that day you are coming back home late. But for a city bike that is used regularly, parked outside regularly, and used "any moment" (without previous thought and preparation to collect "all your gear"), dynamo lights are best. For 30EUR you can already get online decent LED front lights with 30 or more lumens, more than enough for a city environment and even ok in darker areas. Nearly maintenance free, always "charged", and worry free as you don't need to take them out of the bike when parked and bring them back later.

In Germany, the safety freaks, battery lights were only recently deemed legal for urban riding (before were only allowed in bikes lighter than 11 kg). All new urban/city bikes come equipped with dynamo lights, even the children bikes. For this same reason, German online shops are the best and cheapest to buy dynamo kits.

 

[hamster]

Agreed, dynamo plus LED lamp is a really good solution. The problem with the big off-road LED lamps is that they have no beam-forming and dazzle badly in traffic.