| Bicycle Dynamo Generator 12V 6W

This bike generator is a gem! I have five (count 'em 5) of these puppies and they have been working for over 4 years and doing a bang up job of providing outstanding lighting for three bikes in our family. I just bought 2 more from Amazon's original vendor for future projects. No, the plastic wheels have not worn out but go ahead and put "O" rings on them if it will make you feel better. It is a good idea however, to "lock" the jam nut on that spinner with a drop of penetrating lacquer.I finally decided to write a review because there were only 3 good reviews and a couple of crummy ones written by people who apparently, did not know a whole lot about the product they had purchased. At the risk of raising the price, I'm here to tell you that this is the best buy and the best performing bottle generator available ANYWHERE, bar none! Even with the extra six bucks for shipping, it is a bargain.IT IS IMPORTANT to understand that this well-built unit has two generating windings and that they share a common ground point at the case mounting bracket. The 2 windings are NOT in phase and they are intended to drive two separate lighting circuits! There are THREE electrical connections to this generator. One, marked "H" is for the headlight and this delivers ~12 VAC between the "H" terminal and the case/mounting ground bracket. The other one marked "T" is for the tail light and delivers ~3.6 VAC between the "T" terminal and the case/mounting ground bracket. These windings cannot be combined in any simple way, so don't try. If you do, in series they will "buck" each other, and in parallel they will load down each other. Those two terminals that you see, go to two separate windings of different thickness wire whose other ends share a common connection at the case mounting bracket.Granted, the instructions are inadequate, but the product itself is superb.To reiterate, THIS IS NOT A SIMPLE GENERATOR. It is actually two generators of differnt voltages and different capacities, in one package. If you drive incandescent lamps (a 12 V headlight and a 3 V tail light), you will have no problems except periodically replacing the burned out bulbs. Just remember that this is a THREE wire, dual lighting system. The Bike frame is the SINGLE return "wire" for each of the two lighting circuits and connects to the generator through a pointed set screw on the mounting bracet. The set screw is cranked in until it shatters the paint and galls itself into the frame by dimpling it. When fresh, the connection offers a relatively low resistance to current flow but over time, it loosens and corrodes and needs to be cleaned and retightened. Similar connections are provided on the headlight and the tail light.In practice, I like to attach two well soldered wires to a single large ground lug and, using plated star lock washers, compress it securely onto the main mounting bolt right at the generator, where it will stay put and not deteriorate. Then, with the "H" and "L" terminal wires, I now have FOUR wires leaving the generator, a pair for the headlight and a pair for the tail light. Expect 12 VAC at ~ 0.480 Amps from the headlight circuit and 3.5 VAC at ~0.100 Amps from the tail light circuit. I prefer to run double wires to the lights, say 18 gauge to the tail light and 12 gauge to the headlight rather than the old fashioned and shakey practice of using set screws and the bike frame as the return conductor. Since we are using low voltages, speaker wire works just fine. It is super flexible, easy to find, and looks really spiffy.THIS IS AN A.C. GENERATOR. So if you are using LED's, when you build your lightoliers, you will be best served by employing Schottky diode rectifiers, super caps, 2 parallel full wave series strings acting as reverse voltage snubbers, proper heat sinking and all the rest of the good stuff that makes for decent engineering. In short, you should really know what you are doing.The GOOD NEWS is that a generator is ideally suited to power LED's. LED's need to be current regulated, period! An LED is a current SINK. A generator is a current SOURCE. If you set up your LED lightoliers so that they can handle the current output of your generator, the generator will automatically voltage limit to provide it's maximum design current. In other words, an LED headlight assembly that can absorb 750 ma. at 10 volts, will keep THIS generator output (to the // LED strings) at 10 volts up to 750 ma. of current draw. Because this is more than 6 Watts, you can't burn it out! The same design goes for the tail light assembly. Now this means that you will not get all of the lumens out of your LED's that they are capable of producing but you will get all of the light that this 6 watt generator will deliver. Take it from me, with the new Luxeon Stars this is a WHOLE LOT more than you will see from incandescents and your LED's will last longer than many bikeframes.Write me for particulars about sources and configurations for DIY bike lightoliers. If you build your own, you can light up any trail on the darkest of nights and all the pavement and road signs for a block ahead when you're cruising in town. With such a capability always with you, your 24 hour bike riding gains spontaneity, true safety and becomes more fun. Instead of merely being seen, you can see as well as with a single car low beam, even at moderate speeds.To recap, this generator will deliver the goods. Mechanically, the bracketting is twice as heavy as any 6 V bottle or those cheapy (but more expensive) 12 V combo packs you see. So disregard the naysayers and grab one of these babies while you can (the price keeps going up but the supply seems stable). Find a Radio HAM to help you if you need it, you won't be sorry and you'll make a new friend. A little timid? Consider the following: By adding approximately $80 in parts to the $34 you spend for AC power, you can easily put those $1600 OTC lighting systems to shame and have a bunch of fun in the bargain. The money and aggravation you would spend on batteries and charging schedules is soon repaid and you can feel as green as the eyes of those who watch you light up the night as you speed on by. KI6W

UPDATE4:A tip. I found that to prevent the plastic friction wheel from wearing out, you need to align the friction wheel properly against the bike wheel.Make sure that the vertical grooves on the friction wheel is aligned with the radius of the wheel. The problem is, dependingon your bike frame, sometime this is not possible.--------------------------------------------------------------------------------------------------------------------------------UPDATE 3:A warning! if your bike frame has an oval cross section instead of circular, you may not be able to properly install this dynamo.One of my bikes has an oval cross section in the back and I could not install this dynamo there. I had to install it in the front.-------------------------------------------------------------------------------------------------------------UPDATE 2:I discovered that in the rain, the plastic friction wheel will wear much much faster than riding without the rain.--------------------------------------------------------------------------------------------------------UPDATE:Just to let you know, this dynamo can handle the heavy rain very well. It just get better as I use it. You will never findany bottle dynamo like this one.----------------------------------------------------------------------------------------------------------------Wait for the price to come down before you buy. It should be about $17I had a good feeling about this generator and it was confirmed when I received it. This generator hasthat classic traditional look, so it does not look slick or high tech but it is rugged and it does deliver.Everything the other reviewer B. E. Sharrow said about it is true. The metal bracketts that is used to mountthe bottle generator is maded of steel and is very strong. It has just the right voltage, Amps, and Wattsthat it claim and is also what I am looking for. Yes, the drive wheel is made of plastic and other reviewersfear that it will wear out but the plastic is hard and tough that I am not concern. Beside for my purposeI want the drivewheel to spin as fast as possible so the "O" ring or the cap protector will not work for me.And also No, there is no instruction but it is very obvious how to install this. But if you need help, there isa blog for this purpose. I can not post a link here so just Google "Tung Lin Dynamo" and pick the linkthat says "Bless This Bike: Do It Yourself, and if you CAN't...".. Also make sure you read B. E. Sharrowreview here. There are some useful info. there. Anyways one thing you might want to pay attention to is thespring loaded lever that engage the dynamo. When you press that lever, the dynamo drivewheel should makea quick snap, swinging it toward the tire. If it swings away from the tire, then you are not installingit correctly. In this case, by switching the generator to the other side of the "fork" and fliping thebrackett over, you may arrive at a more correct orientation.I have identified three different points on the bike that satisfy the above requirement. Of these, onlyone is on the back wheel and it is on the left side of the bike - the side without the chain.On the front wheel, if you mount it on the right, the generator must be in front of the front fork.But if you mount it on the left front wheel, the generator must be behind the front fork.Also to mount the generator on the front wheel, you must buy two longer bolts and nuts, if your front fork is too thick.In my case, the size of the bolts is: Crown Bolts, Hex Bolt M6-1.0 x 40mm Zinc Plated CB# 35828and the size of the nuts is: Crown Bolt, Hex Nuts M6-1.0 Stainless Steel CB#00188This generator is the only brand that I found that is rated at 12V 6W. Most bike generators including thehub ones are rated at 6V 3W. And with all the high tech stuff, I got the feeling these generators will notbe around for long.-----------------------------------------------UPDATE----------------------------------------------------I have been curious about the electrical characteristics of this dynamo. I decided to settle the issue. I deviced a way totemporarily mount a multimeter on my bike and attached the test leads to the output terminals of the dynamo. In this way, asI am ridding my bike, I can measure the AC voltage of the dynamo. Also with my bicycle computer, I can read off the speed atthe same time. Here is the results:At 15km/hour, I got about 15V AC. At 20km/hours, I got about 24V AC (both without load). As far as the Amps, my meter does notsupport AC Amps below 1Amp so I could not measure. Note, with a load connected, the voltage will drop considerably-------------------------------------------------------------------------------------------------------I mounted two of these on a mountain bike and connected them in parallel to get enough voltage (12V) andAmp (1A) to charge a big laptop battery pack. It works like a charm. It will take about 8 to 10 bikinghours, but it does work.So if you don't have access to the grid, and you must charge your power hungry laptop while biking and have itready for use at your destination, this is the best way (maybe even the only way) to do it.Here is some dimensions of the generator bottle just in case you need them:weigh: 0.75 lb. or 0.34KgDrive Wheel diameter: about 19mm or 0.74" which means at biking speed of 15km/hr or 10mile/hour it willspin at about 4200 RMPLower Diameter: 4.46cm or 1.75"Smaller Upper Diameter: 1.37cm or 0.54"Total Heigh: about 11cm or 4.33"Heigh of lower generator body: about 4.5cm or 1.77"

I thought i was to get the light kit with it. cost to much for what you get. found same generator with front and back lights for 5 dollars less. works good, but not enough product for the money.