how to mount a bottle dynamo?

[keithb]

Hi all,

I'm considering switching to dynamo lighting for commuting next winter, but have some questions that I could do with some help with, if possible.

Firstly, I'm looking at a bottle dynamo for now, as the time and cost associated with a hub generator is too much at the moment.

My bike is modern, with disc brakes, allow frame and carbon forks... And no dynamo mount! So how can you mount a bottle dynamo to such a frame? It's a trek crossrip by the way.
Also, as the rim's don't have a braking surface, can a dynamo run on the rim, rather than the tyre? Would it need a special or modifies roller?

I'll be looking to power both front and rear (mudguard) lights.

Also, do lights and/or dynamo's come with all the connectors wiring in general?
Cheers,
Keith

[mercalia]

I suspect with great difficulty. At the front carbon forks and no cantilever bosses to use as a bracket attachment? On the rear wheel maybe. But alloy frame easy to damage by attach a steel bracket.....?

[fatboy]

I would recommend using the rear wheel as I find it less noisy there.http://www.sjscycles.co.uk/busch-and-mu ... prod11215/ would be quite a good solution.

Much as it pains me get dynamo stuff from Germany. Rose bikes or bike24 do very good deals. You might find you can go for a hub dynamo instead.

[[XAP]Bob]

Rear wheel...

[Brucey]

bottle dynamos tend to work best on braze-on brackets, or failing that on canti bosses. After that they tend to be a bit flaky, (and so might your paint be... )

One trick is to use a seatstay clamp bracket, with rubber padding, and then brace this against turning/provide a ground connection by making an angle bracket that goes up to the mudguard mount on the seatstay brace.

The rim paint/anodising on a disc-only rim will wear through if you use a rim drive dynamo; it is just a matter of time really.

Personally (for regular use) I'd favour a hub generator too; it needn't be dreadfully extravagant in price.

Generators usually come with any special plug they need, but no wire. Front lights usually come with enough wire to reach a front generator (sometimes more), and rear lights don't always come with wire; so you usually need more wire for the rear light, and sometimes the front light too. The rear light connections are often onto the front lamp body, and may need additional connectors; this varies with lamp design though.

Even if you plan on a bottle generator in the short run, it might pay you to get lights which are switched, in case you convert to a hub generator later on.

cheers

[mjr]

http://www.maplin.co.uk/p/maplin-equipm ... -10m-fa26d is readily available and I think it's OK for extra wiring (3W/6V = 2A right?) but might not be exactly what I used. From memory, I've also used heatshrink tubing (for protecting the connectors against the worst of the weather), electrical tape, various coloured cable ties, wire stripper/cutter/crimp, a craft knife, a hairdryer that gets hot enough to shrink the heatshrink and a heatproof mat to protect the paintwork while applying heat nearby. Nothing expensive, but annoying if you start fitting things, need one of them and haven't got it to hand.

[mercalia]

Rose have twin cable to go to the rear at a not too high a price and with slip on plugs commonly used
obviously buy as part of a larger order
http://www.rosebikes.co.uk/product/detail/aid:51531

[fatboy]

Personally (for regular use) I'd favour a hub generator too; it needn't be dreadfully extravagant in price.

http://www.bike24.com/1.php?content=8;n ... ;orderby=2

[keithb]

Thanks all, I have been looking at some of the German sites but that Bike24 fatboy linked to wheel is by far the best value I've seen.

May have to reconsider the options now, as the bottle was kind of meant to be a cheap interim solution (for maybe some years) until a hub-dynamo was affordable...

Need to rethink that now!

Cheers all,
Keith

[Brucey]

http://www.maplin.co.uk/p/maplin-equipment-wire-16-02mm-black-10m-fa26d is readily available and I think it's OK for extra wiring (3W/6V = 2A right?) ... .

6V, 3W = 0.5A.

Most hub generators will just about scrape 0.6A or 0.7A into a low resistance load, so they work quite well as ~0.5A current sources into a typical load.

cheers

[markfh]

If you are looking at various bottle dynamos it is worth remembering that some are designed to use the frame as as the return path and make the connection to the frame via a screw though the clamp that clamps on to the fork/seat stay - it is the thread hole visible in the Busch & Muller High Quality Aluminum Stay Fitting Bracket linked to in fatboys post above but other clamps have similar threaded holes/screws. I personally don't like the idea of connecting to the frame in such a manner as you are, of necessity, damaging the paint if not the actual tube. If using such a clamp I prefer to omit the screw and run a separate return cable from the dynamo/clamp to the both the front and rear lights, possibly combined with the normal feed using either a twin cable or a figure of 8 cable.

[mercalia]

If you are looking at various bottle dynamos it is worth remembering that some are designed to use the frame as as the return path and make the connection to the frame via a screw though the clamp that clamps on to the fork/seat stay - it is the thread hole visible in the Busch & Muller High Quality Aluminum Stay Fitting Bracket linked to in fatboys post above but other clamps have similar threaded holes/screws. I personally don't like the idea of connecting to the frame in such a manner as you are, of necessity, damaging the paint if not the actual tube. If using such a clamp I prefer to omit the screw and run a separate return cable from the dynamo/clamp to the both the front and rear lights, possibly combined with the normal feed using either a twin cable or a figure of 8 cable.

Well the B&M dynamo isnt one of them as it has 2x2 connections "earth" and "live".

[WOOLIFERKINS]

You can mount a bottle dynamo on the rear seat stay with one of these Both extra cable and connectors are available. Don't try and earth through the frame it's a quaint historic practise that doesn't work with modern lights. Fine in its day but duplex wiring is the way forward. Remember when buying from mainland Europe if you have any warranty issues you'll have to deal with them and shipping costs become a bun fight. I would also say go for a hub dynamo first you won't regret it.

[robc02]

If you plan to mount a dynamo on the seatstay check it doesn't interfere with any rack you have or may wish to use in future.
I had to move a B&M from behind the RH chainstay to in front of the LH chainstay for just this reason.

[ukdodger]

Rear wheel...

Front. They're easier to turn on and off.