3 Watt LED Bike Light Experiments
June, 2008, Rev f
Michael Krabach

Contents

Introduction
Synopsis of Experiments
Prototype 1 - Resistor Controlled Prototype
Prototype 2 - Triple Cree with large heat sink
Prototype 3 - Double Cree with Individual regulators
Prototype 4 - Single Cree and regulator
Prototype 5 - Single Cree and regulator
Prototype 6 - Triple Cree revised heat sink
Prototype 7 - Triple SSC in C Mag-lite Head
Prototype 8 - Triple Cree in D Mag-lite Head
Prototype 9 - Prefabricated 3 LED Mag-lite Head
Prototype 10 - Red flasher with Wide Optic Lens
Prototype 11 - Yellow flasher no Optics
Prototype 12 - Red flasher no Optics
Prototype 13 - Red flasher two LEDs
Prototype 14 - Triple Cree with 8 deg Optics
Prototype 15 - Red flasher two Cree LEDs
Prototype 16 - Red flasher two LEDs Clear Case
Prototype 17 - Auto 12 v clearance light
Light and Beam Measurements
Conclusions, Recommendations, and Further Speculations
Summary Table and Parts Sources

Synopsis of Experiments

Prototype 1 - This light utilized a 3x3x1 watt modular 10 watt LED with a resistor controlled current. The heat sink is a surplus TO-3 type power transistor and the reflector is from a Mag-lite. All handlebar clamps are spring loaded wood clamps. It uses a 12 volt gel cell. Weight 6.2 oz.

Prototype 2 - This light uses 1/3 of a large heat sink from an surplus linear power supply. The three Cree 3 watt LEDs are in series powered by a 1000 ma Buckpuck with variable output. A shield was added on the top to stop the LED glare in the riders eyes. It uses a 12 volt gel cell. Weight 8.3 oz. My favorite bike light for general road riding.

Prototype 3 - This light uses two Cree 3 watt LEDs. Each LED has its own current regulator (at 550 ma) with a clicky switch. Can ride with one LED for low brightness or both LEDs for greater brightness. Partial cooling fins from a 486 CPU were added to enhance the heat dissipation. The light uses 1 aluminum angle stock. A 6 volt lantern battery or 4 NiMH AA batteries are used for power. Weight 6.5 oz. My favorite prototype for bike paths.

Prototype 4 - This light is a simplification of the one above using only a single 3 watt Cree Q5 Bin LED powered by a 1000ma AMC7135 type current regulator. The light uses 1 aluminum angle iron and a surplus heat sink from a TO-3 transistor assembly. A 6 volt lantern battery or 4 NiMH AA batteries are used for power. Weight 3.5 oz.

Prototype 5 - This light is the same as the one above except I needed a design that did not use the power supply heat sink. Here heat sinking is all from locally available 1 and 3/4 aluminum angle stock. The 3 watt Cree LED is powered by a 1000ma AMC715 type current regulator. A 6 volt lantern battery or 4 NiMH AA batteries are used for power. Weight 3.5 oz. Favorite prototype for emergency light using the 4 AA batteries.

Prototype 6 - This light is a variation on prototype 2 except I wanted to construct one without using the surplus heat sink The heat sinking is all from 1 and 3/4 aluminum angle stock. The three Cree 3 watt LEDs are in series powered by a 1000 ma Buckpuck with variable output. It uses a 12 volt gel cell for power. Weight 7.7 oz.

Cheap 20 Watt Bike Light - This is the 12 volt halogen M-16 spot light I am trying to replace with LED lamps. It is powered by a 12 volt gel cell. It is the prototype for the following variations. Weight 8.5 oz.

Prototype 7 - This light uses three 3 watt SSC LEDs in series powered by a bFlex programmable current regulator. The optics are a tri-optic reflector which fits the proper depth of Mag-lite C flashlight head. A film canister was used to close of the rear of the unit. It is powered by a 12 volt gel cell. Weight 8 oz.

Prototype 8 - This unit uses a Mag-lite D flashlight head with the battery barrel cut short. There is more room inside for electronics. Three 3 watt Cree LEDs in series are powered by a 1000 ma Buckpuck with variable output. A tri-optic reflector was found that fit the depth of the head. It is powered by a 12 volt gel cell. Weight 9.5 oz. My favorite (1912 tri-optics) for straight busy roads, not wanting to blind oncoming traffic.

Prototype 9 This light is similar to Prototype 8 but uses a prefabricated three 3 watt emitter module which eliminates having to mount 3 LED's on a homemade heat sink slug. This considerably speeds up construction of this light. The C head and body makes installing a 1000 ma Buckpuck and 5K ohm pot a tight configuration. It is powered by a 12 volt gel cell. Weight 8.5 oz.

Prototype 10 This rear flasher uses a 3 watt red Cree LED and a 17 multi-mode controller to give a very bright tail light. The controller will hold the last setting when turned off. An oval sub-lens (8x25) creates a wide rear beam. Powered by one AA battery, will last 6 hrs in warning flasher mode. This unit has enough heat sink to be used on steady high mode. It is highly visible from the side,

Prototype 11 This flasher was an attempt to mount a LED and flasher controller inside a VistaLite case. A white 3 watt Cree LED was used. A multi-mode flasher has 5 modes and but does not hold the last setting. This unit should only be used in a flashing mode or low mode, but not the high mode because of the small internal heat sink. It used 2 AA batteries and will last only 4 hours on flashing mode. This unit is much brighter than the original VistaLite Xenon strobe flasher.

Prototype 12 This flasher used the same components as prototype 10, but with a single clicky switch and no L2 optics or sub-lens. This was an attempt to create a weather resistant flasher, like Prototype 11, that is less prone to damage like Prototype 10. The single AA battery will last about 6 hours. The lack of the L2 optics does not diminish the visibility of the flasher by much. This is my favorite tail light.

Prototype 13 This flasher uses two 1 watt red LEDs in series with a 17 multi-mode controller. The beam pattern is taller and wider and not so well defined as prototype 12. It is also not as bright as prototype 12. This flasher uses a single AA battery and will last over 24 hours.

Prototype 14 This unit is the same as Prototype 6 except the optics have changed for 8 degree snap on lenses. The resulting beam pattern is quite narrow, but very bright and good for long distances. The three Cree 3 watt LEDs are in series powered by a 1000 ma Buckpuck with variable output. It uses a 12 volt gel cell for power. Weight 7.7 oz.

Prototype 15 This unit is an adaptation of Prototype 13 but using Cree red LEDs. The case and regulator is the same. Because of the size and placement of the LEDs, the beam is shaped slightly narrower than Prototype 13. The light is very bright. This flasher uses a single AA battery and will last over 24 hours.

Prototype 16 This is the result of using an off the shelf commercial flasher in place of the old Vistalite flashers, which are scarce. The LEDs used are the generic red LEDs used in Prototype 13. The cover plate is clear so the light has a very wide field of view. The flashes stand out because from a distance they seem as very bright pricks of light. I run it in the police (warning) flashing mode. This flasher uses a single AA battery and will last over 24 hours.

Prototype 17 - This is an adaptation of the commercial LED clearance light for a car or truck. It uses 12 volts directly from a gel cell. This tail light is used in combination with the triple LED front lights which use a 12 volt gel cell. Very effective tail light.