Halogen bulb for dynamo headlamp

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Steve
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Halogen bulb for dynamo headlamp

Postby Steve » 9 Mar 2013, 5:45pm

I've just had to replace the bulb in my headlamp. Until now all the push-in type bulbs I've had have dropped easily into the front part of the light, but in the replacement I've received, the little notch in the bulb flange is on the small size, and so I had really to push the bulb into the holder, where it lay at a slightly awkward angle and so didn't sit well when the lamp was re-assembled. Have sent bulb back to the supplier as faulty, but would like to check if anyone else has had a similar experience, or am I just being too fussy?

Given the difficulty in getting 3w bulbs I'm now wondering about replacing the lamp with an LED model but there's quite a jump in price - so if anyone can recommend an LED dynamo light that gives equivalent illumination but doesn't cost more than my old steel frame is worth, please let me know!

PT1029
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Re: Halogen bulb for dynamo headlamp

Postby PT1029 » 9 Mar 2013, 6:06pm

Bush and Muller LED front dyno lights now start from £18.50 rrp : -

http://www.amba-marketing.com/amba_cata ... r=1m7b0s99

I'm sure someone out there can convert lux into watts output.
Amba used to list the basic B&M halogen model at £15, but don't seem to anymore.

pete75
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Re: Halogen bulb for dynamo headlamp

Postby pete75 » 9 Mar 2013, 6:24pm

This is excellent value a 30 Lux led for under 13 quid. Axa is decent quality too.

http://www.rosebikes.co.uk/products/bik ... eadlights/
Last edited by pete75 on 9 Mar 2013, 7:20pm, edited 1 time in total.

Steve
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Re: Halogen bulb for dynamo headlamp

Postby Steve » 9 Mar 2013, 6:45pm

Thanks, yes the Pico 30 looks a real bargain - not much more than the price of a few halogen bulbs - anyone have any experience of it? (it says new so probably not!!!)

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gaz
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Re: Halogen bulb for dynamo headlamp

Postby gaz » 9 Mar 2013, 7:39pm

You could try a LED bulb.
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tyred
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Re: Halogen bulb for dynamo headlamp

Postby tyred » 12 Mar 2013, 11:45am

Very satisfied Axa Pico user here. Excellent beam pattern and the light is white, not blue tinted like some other LED lamps I had tried in the past.

Just be careful, the most basic model has no standlight, as I have found out after ordering it. I expected all modern LED lamps to have one. My Lumotec Halogen on my other bike even has one.

MikeF
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Re: Halogen bulb for dynamo headlamp

Postby MikeF » 12 Mar 2013, 11:55pm

gaz wrote:You could try a LED bulb.

They are good with battery powered lamps. Have you tried this with a "Dynamo"? Isn't the "dynamo" actually an alternator producing an AC voltage. If so you will be relying on the reverse voltage protection built into these replacement bulbs. I don't know how good that is - could only be that of the LED itself, which is of course a diode. If the voltage is AC, you will get half wave rectification, and a reduction in power output, but even this may give a better light than a filament bulb. I must obtain a hub "dynamo" to try out for myself.
"It takes a genius to spot the obvious" - my old physics master

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andrew_s
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Re: Halogen bulb for dynamo headlamp

Postby andrew_s » 13 Mar 2013, 2:43pm

PT1029 wrote:I'm sure someone out there can convert lux into watts output.

Unfortunately not.
Lux is how brightly something is lit (a wall 10m from the light in German standards speak), and ignores the size of the lit area. It depends on how the light is focussed, so with a bare filament bulb you might need 40W to get 30 lux, but with a diode laser it might be only 1mW.

Back on subject, I'd recommend a new light over an LED bulb. LED bulbs have a very different light distribution from filament bulbs, and the reflector in the old light will be fairly useless, being designed for filament bulbs.

james01
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Re: Halogen bulb for dynamo headlamp

Postby james01 » 13 Mar 2013, 4:03pm

tyred wrote:Very satisfied Axa Pico user here. Excellent beam pattern and the light is white, not blue tinted like some other LED lamps I had tried in the past.

Just be careful, the most basic model has no standlight, as I have found out after ordering it. I expected all modern LED lamps to have one. My Lumotec Halogen on my other bike even has one.

+1 for the Axa Pico, I bought the base model for Euro 10.90 and it's not far off my much more expensive B&M Cyo in performance. Lack of standlight doesn't worry me, in the unlikely event of halting in the road with oncoming traffic coming straight at me I have a cheap battery LED as backup.

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Audax67
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Re: Halogen bulb for dynamo headlamp

Postby Audax67 » 13 Mar 2013, 5:28pm

pete75 wrote:This is excellent value a 30 Lux led for under 13 quid. Axa is decent quality too.

http://www.rosebikes.co.uk/products/bik ... eadlights/


Not to hijack the thread, but have you any idea how polite these things are when it comes to interfering with other electronic kit? I have a computer that goes wawa when I use an IQ Cyo but not with a 2008 IQ Fly. I'd like to stick a second Fly in the circuit, but I'm chary of the newer ones because they've probably changed the electronics.
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nickpaton
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Re: Halogen bulb for dynamo headlamp

Postby nickpaton » 13 Mar 2013, 8:45pm

LED bulb
MikeF wrote: They are good with battery powered lamps. Have you tried this with a "Dynamo"? Isn't the "dynamo" actually an alternator producing an AC voltage. If so you will be relying on the reverse voltage protection built into these replacement bulbs. I don't know how good that is - could only be that of the LED itself, which is of course a diode. If the voltage is AC, you will get half wave rectification, and a reduction in power output, but even this may give a better light than a filament bulb. I must obtain a hub "dynamo" to try out for myself.

Reading further down the page of the site, they address this in some detail in "NOTE 4. DYNAMO VOLTAGE REGULATION", and lists various dynamos, and whether a regulator is needed.

nickpaton
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Re: Halogen bulb for dynamo headlamp

Postby nickpaton » 13 Mar 2013, 8:58pm

Audax67 wrote:Not to hijack the thread, but have you any idea how polite these things are when it comes to interfering with other electronic kit? I have a computer that goes wawa when I use an IQ Cyo but not with a 2008 IQ Fly. I'd like to stick a second Fly in the circuit, but I'm chary of the newer ones because they've probably changed the electronics.


In another life I used to prepare electronic equipment for approval testing, especially electrical interference, and it's unlikely simple regulators from the items you mention will cause any interference at all. There may be some issues if switch mode devices are used to regulate or voltage change, but legally it will have to be within approved limits and therefore shouldn't cause problems with other items.

Also before anything can be sold in Europe it has to be CE Approved which will include strict electronic interference limits. This is where grey imports can be a real nuisance as they are "smuggled" in with no approvals and will merrily interfere with all in sundry!

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interestedcp
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Re: Halogen bulb for dynamo headlamp

Postby interestedcp » 13 Mar 2013, 9:56pm

Audax67 wrote: Not to hijack the thread, but have you any idea how polite these things are when it comes to interfering with other electronic kit? I have a computer that goes wawa when I use an IQ Cyo but not with a 2008 IQ Fly. I'd like to stick a second Fly in the circuit, but I'm chary of the newer ones because they've probably changed the electronics.


It isn't so much the electronics as the shielding that makes the B&M Cyo problematic with very sensitive wireless cyclo computers. The SON Edelux light has a metal housing, so it makes very little RF noise, even though its innards are identical to the B&M Cyo (licensed). If I correctly recall some test I read some years ago, it doesn't disturb wireless cyclo computers, even at very close range.

Some wireless cyclo computers have bad "analogue" designs, that easily pick up RF noise, distance between LED light and computer plays a role too, so the effect of the RF noise can be hard to predict. Good quality wired computers can be had for cheap, or advanced GPS cyclo computers have fallen in price too. Both solutions are immune to such RF noise as modern LED lights make. Not much aesthetic value in a wireless computer either, since you have to run a wire along the fork to the hub dynamo anyhow.
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