Dynamo vs Electromagnetic Induction

[TrailRat]

OK, so I'm looking for some lights for Camille. Preferably LED and I'd really like to go with a dynamo.

On my travels, thanks to Google, I found something called an Induction generator! If you're unwise to the concept then basically from the looks of it, you strap two magnets to your back wheel and as you pedal you make electricity! Or something along those lines.

Anyone tried it? What do you think?

I know I don't want to go down the dynamo hub route though so just surfing for ideas!

[Smut Pedaller]

Reelights are a commercially available induction system
http://road.cc/content/review/14883-ree ... -light-set
From what I've seen most electromagnetic induction lights are similar and only flash, someone correct me if I'm wrong. They seem to be mostly a "be seen" type light rather than a seeing light.

I won't start on dynamo lights as they are pretty well covered, but if you don't want to go down the hub dynamo route what about a sidewall dynamo?

[gentlegreen]

How much do you value your personal safety ?
I value mine at significantly more than £100, and a lot more electrical power than I could easily generate myself.

I want 4 watts of LEDs minimum on the front to make an impact in traffic.
If you need to see where you're going on unlit roads you need a lot more - in my case a couple of 5 watt LEDs.

I've yet to see any single front light on a bike that satisfies the dual needs to see and be seen. A good dipped beam is the most difficult thing to achieve.

The only ready-made lights I would consider would be something like the Philips for front and a couple of decent half watt rear lights (you should have a backup) - though I've been impressed by the 1 watt B&M CYO - though it isn't enough for me.

You won't power those from a couple of magnets strapped to your spokes - that's for cycle computers, not lights.

[Valbrona]

I think you might want more of a 'shed project' over the winter months than practical lights, so the dyamo option is probably best for you.

If you only need lights so that you are seen, rather than those that light up the road, modern LED lights are easily good enough.

[Ayesha]

One recent project of mine was powering a 3W LED torch off a Sturmey Archer dynohub. I constructed a Full Wave Rectifier unit inside the torch where the batteries usualy lived.

It worked great.

I used a battery powered Rear LED lamp.

The Sturmey hub produced 1.8 W and the Cree LED required 0.8 W to start and 1.6 W to be pretty damned bright.

A 'nominal' 5W Cree LED torch unit will start at about 1.0 W and give good brightness at 2.8 W, so can be powered off a Shimano or B&M 3.0 W generator.

A sidewall bottle dynamo should do the business.

[james01]

I've yet to see any single front light on a bike that satisfies the dual needs to see and be seen. A good dipped beam is the most difficult thing to achieve.

.

I'm very satisfied on all counts with my B&M Cyo powered by a sidewall dynamo. Are you sure it's only 1 watt? The stated nominal wattage is 2.4watts, and it certainly outperforms my 3 watt Cree LED torch.

[alicej]

I've got Reelights (the kind with magnets). I love them because they're fit and forget, but if you go for them make sure you get the right ones - for ages you could only get the ones which attach right down by the hubs, which is too low, plus not all of them store a charge so they switch off as soon as you stop.

Go for the ones which keep flashing after you stop - they go on for quite a while - and which have an adjustable length of cable between the capacitor and the lamp so you can mount them wherever you like, on the seat post or whatever.

Good enough to be seen by, but I would say they're not powerful enough for actually lighting up the road when you go somewhere dark, so depends what you need.

[[XAP]Bob]

Different ways of generating electricity have different costs.

They all take energy from forward motion - but unless you're racing that's no bad thing (even if training it's good)
They don't take enough to be noticed any more
They are reliable sources of light

Modern LED dynamo lights can be pretty bright - mine is certainly enough to be seen from behind (and frankly I care much less about being seen from in front, but it's the first lamp I've had that I get to see street signs really brightly from a few hundred yards, so they can't be bad)

They are both german (B&M, powered from a SON hub dynamo - which was a revelation after the previous B&M sidewall - much more power to the lights now!)

[TrailRat]

Camille is only a town bike. I can't see us being out anywhere where they don't have street lights or at high speed.


But thank you for the options presented, certainly one to mull over

[[XAP]Bob]

In that case reelights sound like a good option - maybe a battery based additional lamp

[alicej]

Actually I'm about to sell my front Reelight light because I've started using a bar bag all the time and I can't mount it in a spot where it can be seen over the bag. PM me if you might be interested in it.

[Ayesha]

There is also MagTenLight.

[TrailRat]

Actually I'm about to sell my front Reelight light because I've started using a bar bag all the time and I can't mount it in a spot where it can be seen over the bag. PM me if you might be interested in it.

Will it be alright with a basket on the front? I'm hoping to get one for Camille.

[[XAP]Bob]

With a basket you may be able to mount it on the basket...

[BigG]

"To be seen by" lights do not need to be very bright. They just need to catch the eye of other road users. Almost any flashing light does this well and is the hallmark of a cyclist. For additional safety, I find as a motorist that moving reflectors are also very effective. Pedal reflectors are good even though often partially obscured: reflective trouser bands are equally good. Finally, for side visibility those much denigrated wheel reflectors are excellent.