Who sells B&M D'LUMOTEC topal LED front dynamo lamp

[AHB]

Can a UK person buy the Busch & Muller
D'LUMOTEC topal LED front dynamo lamp anywhere (eg mail order etc)?

(http://www.bumm.de/index.html?docu/ledsw.htm)

From their (translated by Google) FAQ web page it sounds very good:

Qtn: Is B&M D'LUMOTEC topal brighter than 2.4W Halogen dynamo lamp?

The brightness depends on the speed.
In the speed range to approx. 18-20 km/h the LED headlight is brighter as the halogen headlights.
At higher speeds the halogen headlight catches up and becomes more brightly than the LED headlight,
the larger brightness goes however expense the expense of the life span of the halogen lamp.
With 6 V our LED headlight is still brighter as a halogen headlight.
The average life span of the halogen lamp amounts to 100 hours with this tension.
With 7 V the halogen headlight is more brightly as the LED headlights, the life span of the halogen lamp amounts
to however only 15 hours.
The question, which headlight is better, must judge everyone by its personal driving habits.
In any case one already produces the LED headlight a homogeneous, broad and very pleasant light field,
at very low speeds. A 12-Volt-Scheinwerfer is however in all speed ranges far superior to the LED light and
the 6-Volt-HalogenlichtAlternat

[Marc]

Have you tried St Johns St bikes Bridgwater : http://www.sjscycles.com/store/vIndex.htm they are big B + M stockists.

Marc

[Simon Simpson]

The 100 hrs down to 15 looks excessive....

a NiMHidride battery lamp maker was over volting by 10% to 13.2 v and the bulb life was reduced but by nothing like those proportions... I have to say I've been using a Shimano Ultegra dynohub on my 20 mile round trip commute..... it is the business...I run it with 2 times 3 watt 6 volt bulbs in series with a switch as recommended by CJ in a post last month. I also have a 1000 candlepower Cateye on the bars which does at lights right turns etc. I've seen the set up oncoming and the Cateye is ultra bright but directional and the two Hella lamps (from ctc shop ) are white but not as bright and far less directional....

On a recent 80 mile night run I switched the cateye off and used the twin Hellas ..in the unlit country road they were streets ahead (pardon the pun)...

The dynohub is unobtrusive and 100% reliable.. no slip no loose wires etc.. I previously used AXA ( on the trailing fork edge to increase traction) and Nordlicht (positioning unimportant) I can't envisage going back to bottle dynamos. The dynohub is on full time as I haven't got round to rigging up a switch.

I'm riding a Xmas 10 tomorrow and I'll be riding my touring bike wuith the ultegra front hub on and twin lamps burning....

The hub was under £50 from Alistair Gow at Wheelcraft 01360-312709..£20 cheaper than StJohn St....

ss

[CJ]

"The 100 hrs down to 15 looks excessive....

No, that's about right. Bulb life is approximately proportional to voltage to the power thirteen – and that's a pretty extreme relationship! But the rated life of the bulbs used in bike lights is usually 200 hours, pro-rata that'll reduced to 30, which isn't so bad. And of course it cuts both ways. Given you spend far more time crawling up hills at 5V than whizzing down them at 7V, the aggregate effect on bulb life is probably more positive than negative.

"A NiMHidride battery lamp maker was over volting by 10% to 13.2 v and the bulb life was reduced but by nothing like those proportions...

Exactly: that's only 10% rather than 17% over-volting, which (assuming an identical voltage/life relationship) cuts bulb life to 30% of its rated value, rather than 15%. Also consider that these rechargeable systems are using general-purpose bulbs. Many of those other purposes involve leaving a light on for long periods of time, so the bulbs have rated lives of at least one thousand hours. Cut this to 300 and it becomes comparable to a cycle bulb, which has already been designed to maximise efficiency at the expense of duration.

In case you are wondering: the brightness of a bulb also varies quite sharply with voltage – to the power of 3.6. That's nothing like as extreme as the life variation, so you cannot take the over-volting very far before the lost life vastly outweighs the illumination gain. For example: that 7V dyno bulb gives 74% more light in exchange for one seventh the life, whereas 10% over-volting gives 41% extra in exchange for one third.

LED's have a much more linear relationship between light and power consumption, which is why they outperform bulbs when the battery is flat or the dynamo is turning slow, but don't do so much with extra power or speed. But they last a whole lot longer anyway.

[CJ]

In reply to your original question, where can you buy a B&M Topal: try www.roseversand.de. I did and they have it for only 17.90 Euros (or 39.00 in the senso version).

[AHB]

The http://www.roseversand.de site just seems to have the standard (non-LED non-D'Lumotec) Topal.

[CJ]

Sorry, of course it is. Try Veloplus (Switzerland). There's also an interesting article (if you read German) at Velojournal.

[AHB]

I havent't had any success trying to order from this website, even using google language tools for translation.
I can add to my basket but I cant get to the buy/register page.

[AHB]

Amba Marketing will be importing the D'Lumotec Front LED lamp. I noticed the Basta Pilot Steady review in the latest cycle. The velojournal pictures made the B&M look brighter but B&M use a separate little LED standlight which presumably means no BS6102/3 K~ compliance when stationary away from kerb. I presume running the same LED from a capacitor means the Basta would comply with the letter of the law (or is it a bit dim because big supercapacitors are expensive).

I have 4AA cells to power my indicator: I have thought I could exploit the B&M LEDs low voltage brightness by isolating the dynamo from DC with two large backtoback Bipolar caps (>1000uF) and feed in 3-3.5Volts dc. At above walking speed the dynamo would take over, but when stopped the main front LED would be at reduced power and the rear at full (because I made the rear circuit myself).

Does the Basta Ray Steady reach full brightness at a brisk walking pace? This is easy to do if manuafacturers would spend the few exta pennies: perhaps the K~ should require it.

[AHB]

I forgot to mention the diode in series with the battery pack.