New second hand bike (which I'll post detail of later, as it contains minor niche content 🙂 ) has come with an Alfine DH-S700 front hub & the snappily named "Lumotec IQ Cyo-T LED Senso Plus Licht 24" front light.
Q: The hub is only 1.5W, is that enough to power this light ? The reason I ask, is that the light does not seem to move up to its "full" setting, I just get a smallish square of light in front of the bike, which I think is its "city" setting. The stand light works. I've Googled but cannot find the power requirement for it, just that it's 6V.
Although I would not be surprised if it's been wired up wrong, tbh.
Most dynamo's are 3W so you're right, it's possible its not got enough to power the lamp.
You can't wire them up "wrong" - the dynamo output is AC, inside the light is a rectifier circuit which converts that to DC.
I've one of the B&M lights and the output pattern is square(ish) - this is because they conform to German road regulations so you don't get the flare that MTB lights produce for example.
1.5W does seem low but a search seems to suggest that the Alfine hub produces the required output, similar to a Schmidt.
Whitestone - when you say square, is it also small ? I'm talking about a patch of useful light that's only a couple of feet square. It doesn't look anything like the pics on the B&M website ([url= http://en.bumm.de/produkte/dynamo-scheinwerfer/lumotec-iq-cyo-t.html ]clicky[/url]).
By wiring it wrong, I meant the input/output of the light, sorry. There's one feed in from the dynamo, and then a feed out to the rear light. If the dynamo is mistakenly connected to the "out" then it might just illuminate the standlight and never the main light, because the light is not seeing an input ? I'll pull it apart during the week. I only picked it up yesterday.
No, my light is closer to that on the B&M site, good enough for 20mph. My light only has one set of connectors, the rear light is simply wired in parallel. You should get a decent output just by spinning the wheel by hand.
Yeah, tried spinning it, and also doing a quick ride round the block. Tiny square of light.
Ho, and, hum.
Bad wiring I hope, otherwise it's new hub time !
I had a 1.5w hub paired with a B+M LUMOTEC IQ Cyo and the light output was very poor. It was insufficient to ride at speed on unlit lanes.
I swapped the hub to a 3w one and it has made a marked difference. The light output now matches the beam pattern images on the B+M website and I can comfortably ride on unlit lanes.
Not sure what wattage your light is looking for but if your hub is too low, then you won't be getting the best from your light.
I had a 1.5v
Watt, not Volt, they're all 6V.
Hmm, looks like new hub then. Anyone want to buy an inadequate dynamo ?
Those 1.5W dynamos are for Bromptons or things with smaller wheels which spin faster, I thought?
1.5W should be enough for most modern LED lights, though you would have to ride a bit faster to get full brightness. It should still be bright enough for most city riding etc.
You can wire it up wrong, if its earthed through the frame/forks. That could give a short circuit.
So make sure you have the earth/live the right way round on the hub and light.
Also not sure about the Cyo T, but its designed to be a daytime running light. Maybe it is set to day mode, so not the full beam? It should use the light sensor to switch to night mode.
they're usually the same power, just a different version of the hub designed to spin faster. Brompton hubs are narrower too aren't they?Those 1.5W dynamos are for Bromptons or things with smaller wheels which spin faster, I thought?
1.5s are for powering smaller be-seen lights on city bikes. Most bright road lights I know of are 3w so you need a hub that can put out that much. You may get more than 1.5w from the hub you have when going really fast, but not 3.
Busch Muller now make specific lights for 1.5w dynamos:
https://www.bike24.com/p2144796.html
I'd imagine even a 1.5w LED is still brighter than the old 3w filament bulbs that were used when dynamos were first used, so may be bright enough for what you want?
Your old Cyo will fetch a decent price on ebay.
Otherwise a new 3w hub. I use a Cyo 80 Premium which is pretty good.
The "T" mode makes the bottom row of LED's brighter and reduces the brightness of the main beam at night. In daylight, it will run like this regardless i think.
FWIW, I think the quoted wattage is what the dynamo produces at a certain speed, and as you go faster it generates more and more volts/power.
This guys using a 2.4w dynamo to run a 40w bulb!:
I'd rather keep the light & upgrade the hub I think. No point downgrading. Thanks all !
Show us the bike then.
🙂
[img] 
?0213193559[/img]
Bloody hell, and, I mean did the OP seriously nearly overlook posting that picture!?
That head tube makes me want to pole dance up it. Extended Frodo anybody?
Five Alive!
That's lovely.
Posh AWOL?
Very nice.
New, or is the previous owner now begging on the streets?
OK, fine, I'll start a "new bike" thread.
😉