Thanks, Guys. 6V sounds good. 12V can be for the cars :-)

As for LEDs, do more watt mean more brighter light? Also, do LED lights burn out ever?

More watts= more light to a point. The optics of the lens and reflector are more important IMHO. Which is why I usually buy B&M lights. I have seen some impressive home built lights too. Most LED lights are purported to be good for 10,000 hours...that is a loooong time to be riding at night, even if you rode at night for 8 hours at a time every night of the year it would take 3.5 years to maybe burn one out.

Aaron

LEDs don't "burn out". LEDs are rated up to 100,000 hours. What this means is at 100,000 hour point,your LED will put out about 70% of the light when new. If you rode for 8 hours a day, your light at about 35 years will output about 70% of the initial light output.

Watts are not really a good way to classify LED lights. It is better to say how many lumens. With incandescent bulbs, a 6v 1 watt bulb will not be brighter than a 6v 3 watt bulb. A watt is a measurement of how much power is used, not how much light is put out. For incandescent bulbs, watts are a good way to determine their relative light output. LEDs are current driven, not voltage driven like incandescent bulbs. If you had two LEDs that were both at 100 lumens at 200mA, with one LED from a 3v bin and one from a 4v bin. Both lights are being driven at 200mA, then they will both put out 100 lumens. The 3v bin LED will use .3 watts and the 4v bin LED will use .4 watts. But the .4 watt LED will probably run hotter. LEDs are less efficient the hotter they are. So in our example the .4 watt LED probably won't put out as much light as the .3 watt LED. But it will indicate how much power you must supply.

But this doesn't mean that a higher lumen LED light will be a better light. As wahoonc said, the optics can make a dimmer light better for riding. You can get more useful light for road riding. I also use B&M lights. They have a nice focused beam. The symmetrical beams of other light manufacturers don't have (not saying they are no other manufacturers with good focused beams) will throw light where it is not needed or even worse into the eyes of oncoming traffic.

^^^^ I got to quit posting while half asleep...

SweetLou has the floor. Not sure where I got the 10k hours from

Aaron

Awesome. Very helpful information. I prefer to go the LED route with good optics, but can anyone explain why LEDs drain less battery than a incandescent bulb with same voltage requirement? (or am i imagining things)

Also, are all dynamos voltage regulated? (eg going fast will not produce more voltage)? If not, how do i find out about it? (I am assuming, if a generator is not voltage regulated, it could burn out a LED as well (while going downhill 40 mph? ) ?

Thanks everyone. The feedback is much appreciated.

Battery drain has nothing to do with voltage, LED, or incandescent. Battery drain has to do with total power used. If you use a dynohub, you don't need to worry about it.

Dynamos are not voltage regulated. The lights are... at least the modern LED lights are. Some old incandescents without regulation could blow the bulb at high speed. Not an issue with modern lights.

If you buying pre-built lights and dynos, none of this is an issue. It'll just work. If you want a DIY setup, then maybe you should learn a little more about electronics first.

I had a 12v Sanyo bottle dynamo 30yrs ago, yes it was bright but it had as much drag as sitting up and opening your jacket does at 15mph, you notice it. 6v hub dynos can put out more than 3watts with parallel lamps.

I don't know of any hub dynamos that are regulated, but bottle dynamos are often regulated.

Today's Power LEDs are putting out over 100 lumens per watt. An incandescent bulb puts out a lot less lumens per watt, probably around 20 lumens per watt. LEDs are just more efficient than incandescent bulbs. That is why batteries last longer, or you can get a stronger light from a dynamo.

Also, with hub dynamos, they are usually listed as 6v 3w systems. This isn't really true, the volts will change with speed. The hub dynamo is more of a constant current supply at 500mA. You can get much more than 3 watts out of a hub dynamo, just by adding more LEDs. You will have to supply more power to the hub though, there is always a trade off.

What SweetLou said. Hub dynamos are, simplistically, more like constant current generators. They are also somewhat self-limiting in current, so you can calculate how much you are over-driving the system. This is why LEDs are wired in series, because there is only a small reduction in current, as opposed to roughly halving it by wiring them in parallel.

I have a two LED homebrew system that works great, though would work better with custom optics. (It used to have three LEDs, but I stupid me forgot to discharge a capacitor one day when I was doing some re-fitting...)

Oops, glad to hear that it was just the LED and not you.

I have no idea if this voltage regulator is wanted or needed but I did find this Shimano SM-DH10:
https://www.starbike.com/php/product_...g=en&pid=11712

I bought a Shimano DH-2N70 on sale on eBay. I know that model is 2.4 watts. From what I read, the 3 watt models are for 2.4 watts for the front light and 0.6 watts for the rear light. If you go to the Busch & Muller website (https://www.bumm.de/), you'll see examples of 25 lux, 40 lux and 60 lux of light. Thing is, there isn't just power. There's also WHERE the beam of light is going. If you look at the peterwhite site, you'll see how one of the B & M models projects the light much closer to the bike. But that one is only 40 lux. At the same time, the model I wanted (Busch & Muller Lumotec Lyt) is only 25 lux but it cost way less at bikexperts.com and I read the beam is sufficiently spread out (although that's not clear in the photo I saw lol). Either way I intend to save more money by just buying a cheap WBT Freedom Ryder 23 rim and DT Swiss Champion spokes.

I'm hoping for the best. One thing I wonder is, what happens when you back up your bike? Would it cause damage to go in the opposite direction? If I take a while before buying a dynamo powered light, can I ride safely on the wheel with the dynamo hub without having a light attached to it?

PeterWhite has the real thing in his light tests. You can see what the different lights do in a fixed situation. All are tested in the same spot. Lots of time involved. I have bought from him with pleasing results. Blues Frog

Short distances of backing the bike up doesn't make any difference. Running the dyno with no light doesn't hurt it either. My city bike has the same hub you are looking at. I power a B&M IQ Fly and a Spanniga LED tail light with it, not problems. The head light has a built in sensor to turn them on and off depending on the ambient light.

I am currently use B&M Lumotec IQ Fly, Lumotec IQ Cyo and a Lumotec Retro. I plan on buying that Cyo Lyt for another city bike that I am building up.

Aaron

No, damage can only travel in one direction. We live in a right hand universe, so damage is always to the right, causing more not less damage. Ok, kidding aside. This won't be a problem. As a matter of fact, you could flip your wheel around and have the connections on the other side and have no problems.

Dynamos are AC and your lights are DC. You don't want DC going in the wrong directions, but to turn AC into DC a rectifier is used. It won't matter which way the hub is rotating, DC will flow in the correct direction.

Riding without a light will also not be a problem. Without the light or if the light is turned off, there isn't a complete circuit so no electricity is flowing.

Just an FYI...i gave my first dynamo a try. I have to say i am very impressed. It's much brighter than i expected, and it only cost me less than $20. It does add quite a bit of resistance when engaged, but not something noticeable when I ride. If i like using this unit, i will eventually upgrade to a hub based dynamo and a better light.

Thanks everyone for pointing me out to the right direction. I am hooked to Peter Whites site. There is so much to chose from, and I'm loving it

Some pics of my power bottle

Anyone happen to know where i could find spare roller for bottle dynamos? The roller that came with my dynamo is plastic (see pic above)..and it will wear out or break sooner or later. It would nice to have a spare. I am not even sure if it's available...i guess...that's what happens with cheap stuff..

Glad to hear you like it. I am a huge fan of dynamo lighting. Bottle dynamos do have higher resistance than hub dynamos. But, they have less resistance when not using the light. If you rarely need the light or don't ride in snow and rain, then I think bottle dynamos are a good choice. My commute home is at night and I ride in all weather conditions, so the hub dynamo is a better choice for me. But I have been thinking about getting a bottle dynamo for my dog walking bike.

I know you can get replacement rubber and wire rollers for the B&M and other dynamos but I don't know if they will fit yours. Call Peter White and ask, he might know.

Replacement part with shipping is going to cost about what your dyno set did...

Aaron

Hey, don't knock 12V systems completely! I've been very successful with a 12V solar charger and 12V battery to handle all my lighting and gadget-powering needs. I plan to supplement this with a 12V dynamo for the dark winter in Denmark.

First (and last) time I plugged in my American battery charger over there, I made the assumption that it would take universal input.

Three seconds later...bzzzzfffft...oops.

That's what got me started on the dark path of dynamo nav.

Yer right, sir. I bought two more units yesterday for $11 a piece including S & H from Amazon (ace hardware). I can't believe how one can make any money off of these units. I believe the bulbs would cost more from Ebay. I got a good deal for a dozen bulbs, but it has no indication of the wattage. I tested the bulbs, and it was bright enough.

Now time can tell how it holds up.

Yeah. I agree. I am now a dynamo convert after only using cheap bottle unit. I wonder what it would be like if i upgrade to some of the mid or higher end dynamo/lights. I dont need dynamo power during summer, but i absolutely will be needing it during dark winter days.

I am thinking of buying a spare wheel and fitting the hub dynamo, so i can switch it during winter period.

By the way, how difficult or easy is it to grease hub dynamo bearings? Any special yearly maintenance needed to be done? Are these brushless dynamos?

You'll find that a modern LED headlight will be much brighter than your light. It will also cost a lot more.

A cheap bottle dynamo with a plastic wheel will slip in wet weather. A nicer bottle dynamo will have a wire roller that works better. A hub dynamo will never slip and has less drag.

Dyno hubs need very little maintenance. I believe the SON doesn't allow maintenance. I have the SON28 and it just works. I have no idea how it's put together inside, but I assume it's brushless, or it would require maintenance.

You probably won't notice much of a difference with the higher end bottle dynamo, they are a bit more efficient, less drag. But, what you will get is a higher quality device that will last a very long time. Higher end LEDs will be more expensive, but they last and last. You won't have to worry about a bulb burning out while going down a dark hill. Then have to replace that bulb in the dark or ride home with no light. Also, the beam is better, as you know from Peter White's site, they will put more light where it is needed.

You can get some good deals with a built wheel on eBay. I'm kind of particular when it comes to wheels, so I build my own, but I was tempted with some of the prebuilt wheels.

The SON hubs use cartridge bearings and hub has a service life of 50,000 km. You won't need to grease the bearings. Shimano uses cup and cone bearings. These can be serviced, but it is kind of tricky, you can easily damage the dynamo. If you don't know what you are doing, I recommend taking it to a shop that knows how to service the Shimano dynamos.