Bike Regulator
Bike Regulator
Lighting Links

Bicycle Regulator

This is a regulator for a 6V/3W bicycle generator system. The purpose is to switch to rechargeable batteries when the generator is idle. In addition, the device limits the voltage across the bulbs when the generator operates at a high speed.
As you can see, the circuit is purely electrical. In the presented design, the switch has been moved, compared to the original to a location where the switch better functions under different circumstances. I kept the regulator on the bike for 2 years during which the circuit operated fairly satisfactorily. Thereafter, I moved on to an electronic regulator optimized for the operation with a hub dynamo.


When the main switch is in the on position, and the generator is not running, the bulbs are fed by five reachargeable batteries. Either NiCd or NiMH batteries may be employed. A running generator feeds the relay, which switches the bulbs to the generator in place of the batteries. Excess voltage across the generator is used to recharge the batteries. The Zener diodes are for protection. The batteries can be further recharged through the charger jack. I have used a 7.2V Radio Shack Battery Charger for the purpose.


As is seen, the circuit, generator, and lights share the ground. All unmarked diodes are 1A Schottky. D1 is some generic all-purpose 1A diode. The low-current polarized DPDT (double-pole double-throw) relay was purchased from Electronic Goldmine. Since many relay manufacturers start their lineup with such relays, you might be able to get one from elsewhere. The relay's line of action goes horizontally across the figure. Different connections and colors are for my own reference.

All elements may be nicely packed onto a 1_3/4"x1_3/4" circuit board and placed, with the 5 AA batteries, switch, mounted LED, and the charger jack, in a 1_5/8"x2"x2_3/4" aluminum box. I have used 800mAh nicads from Radio Shack, which I soldered in series. Currently, higher-capacity NiMHs are available.

I mounted the regulator box on my wire basket. Using reflector holders, it could be mounted on the frame.


I have used a FER 2001 generator and lights with a halogen bulb in the front and with a regular bulb in the back. The regulator ensures that motorists see me at an intersection while I'm standing. The device genuinly gives me more security and the drivers respect me more.

We do not have any hills here, so I cannot assess the operation for a steep climb. A possibility is to include a trimmer resistor in series with the relay for adjustments.


The schematic shown above is the most conservative, letting the generator to take over whenever there is a slightest sign of life from that generator. As the system performed reliably, I decided, eventually, to tip the balance more towards the batteries. Thus, I reduced the capacitor value from 330uF to 75uF (the capacitor affects the delay in the reaction of the regulator) and I put a resistor of 270ohm in series with the relay (the resistor affects the threshold at which the generator takes over). The particular values would, generally, depend on the relay and on the taste, and should be experimented with. In my case, the batteries now take over when the light driven by a generator dims significantly.


to share with would-be designers:
  • The use of Zener diodes for protection, when dealing with such large inductances as that of a generator, or of a charging transformer, is absolutely essential. Without the diodes, you will fry the delicate relay poles in no time. Capacitors are useless for the purpose.
  • Finding a right charging adapter turned out to be quite tricky. I tried a number of them using the generous Radio Shack return policy and buying individual adapters from different outlets.
  • Do not count on the different relay poles to fire simultaneously.
  • Solar cells can deliver a respectable charging current in bright sun. However, the current becomes abysmal under cloudy winter skies. Around here (Michigan) these cells offer no alternative to a generator.
  • Standard battery holders are not practical on a bicycle. The batteries easily pop out.

Another Regulator Version

Someone has asked me for a version of the simple regulator with a full-wave rectification, for a dynamo with separated ground, without the option of charging with an AC adapter, given that batteries could be taken out and charged outside. The schematic and comments are given here.

Dynamo Lighting Links

General Information:
  • Francis Cooke Lighting Pages, BBCi: Bicycle Lights
  • Bikecurrent: List, FAQ, Reviews
  • CandlePower: Bicycle
  • Wikipedia: Bicycle Lighting
  • Dynamo Bicycle Lighting by Wouter H. Scholten, with a strong personal tint
  • Brompton Spotlight on Lights , Dynotest by Chris Juden, Lights by Pamela Blalock and John Bayley
  • Generators for Bicycle Riding by Frank Krygowski and Don Slanina in Human Power (PDF)
  • Myra VanInwegen's articles on lights, Small bicycle lights - a quick test by Günther Schwarz
  • Testing the Efficiency of Generator Hubs by Jan Heine and Andreas Oehler in Vintage Bicycle Quarterly (PDF)
  • Headlight Beams shot by Peter White
  • Articles in ADFC Radwelt (PDFs in German): Overview of Hub Dynamos (05/08), LED Illumination (06/05)
  • 2008 Dynamo Light Comparison of Velociped (PDF in German)
  • Articles from Aktiv Radfahren on lamps & hub dynamos (PDFs in German): 2008, 2007, 12/2005, 2/2005
  • Andreas Oehler in Fahhrad Zukunft (German): Tests of Hub Dynamos, Two-Lamp Tests
  • Veloplus (PDFs in German): Beleuchtung, Fehlercheckliste, Dynamos im Test, Radnabendynamo, Lichttest
  • IG Velo "Licht an", de.rec.fahrrad FAQ (German)
  • RadRatgeber Beleuchtung (history of hub) (in German)
  • Design and Operation of Dynamos by Wilfried Schmidt (German in Fahrrad Zukunft)
  • Dynamos, Peter de Leuw Fahrradbeleuchtung, Stefan Brix Beleuchtung (German)
  • Fahrradbeleuchtung by Olaf Schultz (PDF in German, tons of data, schematics, lamp comparisons)
  • by Olaf Schultz and Andreas Oehler: Fahrradscheinwerfer im Test, Scheinwerfer im Vergleich
  • goniometer results: headlamps street & wall 10m away, rear lamps
  • by Frederic Danjon: Eclairage, L'Eclairage de Velos (French)
  • Iluminación para bicicletas: las dinamos by Martín Dupont (Ciclopedia in Spanish)
  • Verlichting in Fietsersbond Fietsonderdelen (Dutch)
  • Íslenski Fjallahjólaklúbburinn - Rafalar fyrir reiðhjól (Icelandic)
  • Jedź i świeć (Polish), Dinamo u osovini prednjeg točka (Serbian)
  • About Bicycle Reflectors by John S. Allen

  • Principle:
  • How Does a Generator Work?, Bicycle Dynamo - How It Works?,
  • The modern bicycle dynamo - by Guy S.M. Moore in Physics Education (access charge)

  • History:
  • Die Entwicklung der elektrischen Fahrradbeleuchtung (1886 - 1936) by Jos Rietveld (in German)

  • Specific Products:
  • Edelux Lamp by Peter Eland in Velo Vision
  • Dissection of Edelux by W. H. Scholten
  • SON dynamo: Measurements by Nick Ray, SON+Lumotec, 12 V, SON Presentation (PDF in Dutch)
  • Joerg Spaniol & Jan Greune in Trekkingbikein (PDF in German): Schmidt Maschinenbau
  • SolidLights by Pieter Meiring
  • Hella Micro-FF lamp by Chris Wilby
  • Lightspin reviews by Peter de Leuw and Rob Hague & Tim Kirk (PDF)
  • Overhauling Shimano Dynamo Hubs at Trinity Bicycles
  • in German: Dismantling Shimano dynohub NX30
  • in German: Dynamo Axa HR+, Repairing
  • Photo Album: Taking IQ Cyo Apart

  • On-Line Stores (Ordering and an Auxiliary Source of Information):
  • Peter White Cycles (Schmidt, Shimano, Sanyo, Inoled, Dymotec, Edelux, E6, IQ-Cyo, IQ-Fly, Lumotec, Supernova E3, Inolight, Spanninga, brackets, but 'r e-mails may be unanswered)
  • Harris Cyclery (Busch&Muller, IQ-Fly, Lumotec, Schmidt, Edelux, E6, Shimano)
  • OEG Products (B&M lighting; inexpensive dynamo replacement bulbs, brackets 'n shipping, but beware: can ship used stuff)
  • Yellow Jersey (Sanyo dynohub, nearly as much drag w/light off as on; BB Union; Soubitez standlight, Litespin dynamo+Litespin lamp that looks like E6)
  • Quality Bicycle Products (QBP), go to Extended Special Order Catalog e.g. at: Bicycle Habitat, Bicycle Garage Indy (Sram, Shimano, Planet Bike)
  • (Shimano, Union, Planet Bike, Sigma Sport Vario lamp)
  • xxcycle - France with cheap & fast delivery to the US (IQ Cyo, D-Toplight Plus, bulbs, Shimano dynohubs)
  • Jos-International (France, company mail-order w/US delivery of Hella Micro FF- great f/folders - Radius, LED taillights, brackets, cheap!)
  • solidlights (UK, 2*3W LED w/standlight)
  • Britain, ship to US, take CC: St John St Cycles (Schmidt, Pioneer hub, Sturmey Archer, Shimano, B&M Cyo/IQ/Lumotec/Topal, E6, DT Swiss=Bisy, Basta, Jos/Soubitez)
  • Britain - US & CC: Bike Plus (Schmidt, B&M), Bikefix (Schmidt, Axa, basic B&M)
  • more Britain, w/US shipping & CC: Gearshift (Lightspin, Nordlicht, Axa, Renak Enparlite dynos; Basta and Hella lamps; B&M)
  • more Britain: dynamolight! (B&M)
  • Australia: St. Kilda Cycles (some B&M)
  • Switzerland: Veloplus-Shop, vitelli velobedarf (ship to US, payment via bank transfer, many small useful items, Supernova, Edelux, IQ Fly/Cyo, SON, Shimano, Novatec, FER 2002, Union BB, Axa)
  • more Germany: Bicycles Online (Shimano, B&M, Axa, Nordlicht, small parts), Zweirad Weigang (Axa, Basta, B&M)
  • Germany: Rose Versand (CC, ship to US, EUR 18.41+kg*5.62-VAT at writing)
  • Radplan Delta (Novatec hub dynamo, Halo front lamp), Zweirad Experten Gruppe (more German stores)
  • Germany: On-line bike shop for normal riders! (Shimano, FER spoke dynamo), Bikeimperium (Shimano), Berens und Reus (SON, Shimano, Axa, B&M)
  • more Germany: Fahrradversand (take CC&ship abroad, but SH is outrageous; range of Shimano hubs, B&M, Basta/Union, Hella, Axa, Aufa/FER, Renak!)
  • StarBike (Germany; take CC & ship to US, but frivolous SH)
  • Netherlands: Gerritsen & Meijers (importers, SON dynamo, Edelux, B&M)
  • lighting for special bikes: Kinetics (Britain), Pedalkraft (Germany, B&M, SON, ship abroad)

  • Manufacturers:
  • Schmidt Maschinenbau (best hubs, E6 and Edelux lamps), E6 Technical description
  • Busch & Muller (front and rear LED lamps w/stoplights, IQ Cyo, Toplight Line+ TopLight Flat+, E-Werk charger, good bottles)
  • Shimano (several hubs, best DH-3D71/DH-3N71/DH-2N71; Shimano LP-R600 lamp), hu b, lamp technical info
  • Supernova Lighting Systems (Supernova E3 LED lamp - expensive, looks good; on-line store)
  • Philips (SafeRide LED lamp)
  • Renak Enparlite (dynohub from the former GDR, can be mechanically disengaged)
  • aufa (formerly FER, survived unification; makers of lamps, spoke, bottle and block dynamos)
  • Basta, incorporated Union and Soubitez under Marwi, recently acquired by the Dutch Axa (some good bottle and bottom bracket dynamos and halogen lamps)
  • Büchel (lamps, bottle dynamos)
  • Dynosys Lightspin (efficient bottle)
  • Spanninga (Bird-Ekolight headlamp w/backup, Radius, rear lamps w/backup, efficient bottle; used to distribute Pioneer Eurolight dynamo system), Jos (lamps, low-end bottle dynamos)
  • Trelock (LS 885 front & LS 660 back LED lights w/standlight function)
  • Hella (Finnish lamps, including front LED w/battery backup; taken over by Spanninga??)
  • Inoled (Inolight: 1&2W LED headlamps w/standlight function)
  • RMS (low-end, Italy)
  • Planet Bike (dynamo LED headlight with standlight function)

  • Homebrew:
  • Axle Mount for E6 by Benedikt Thum
  • Dynamo powered LED lights by Martin Schmidt
  • LED Dyno Lights by Mike Carden
  • Bicycle Light Projects (dynamo experimentation, LED lights)
  • Generator-Driven LED Headlight by Bill Connell
  • Dual Cree XR-E LED Light by Joe Gross
  • Eigenbau LED-Scheinwerfer mit Hausmitteln by Olaf Schultz (lamp out of 2 Luxeons, in German)
  • Bau eines LED-Fahrrad-Fernscheinwerfer auf Luxeon Basis (Luxeon lamp, in German)
  • LED-Lichtanlage am Liegerad by Herbert Renkewitz (LED lighting system for a recumbent, in German)
  • Dynamo-LED-Treiber (1W Luxeon lighting, in German)
  • 12V Dynamo System (in Dutch)
  • Un feu rouge … LEDs marchant sur dynamo (French)
  • Union generator system
  • Multi-charger
  • Schematics for LED Current Regulators provided by Rob Paisley

  • Off the Beaten Track:
  • Nokia Bicycle Charger for a phone, Pedal & Power, E-Werk
  • Dynamo as a Synchronous Motor
  • Minigenerador Eolico - Wind generator out of a bicycle wheel (Cuba), Catching Wind in Malawi (windmill by William Kamkwamba)
  • Electrification through Bicycle Dynamo (Nepal), Village Lit w/Cycle Dynamos (India)
  • Symphony for Bicycles , veloncell Marcel
  • Dynamo Secession
  • Radio Bicyclette (Katarina Soukup, Montreal)

  • Other Links:
  • Translation Engines
  • Bike Coffee
  • Bike Coffee Addendum (P.D.)
  • Bike Furniture
  • Bicycle Podcasts
  • Muzyka rowerowa (Polish: Bicycle music)
  • Bicycle Haiku (including dynamo)
  • My Electronics Links

  • Occasionally I am going to post copies of sites that have disappeared. If you would like your site to be removed, please e-mail me.

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