Bicycle Lighting Systems

Bicycle Lighting Systems

Bicycle Lighting

Update: 3 November 2010

New MR16 Dynamo LED Page

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This web site details how to
construct a high performance bicycle lighting system

Also contains information on
bells, horns, dynamo powered lights, and other safety devices

Location Makes a Difference

Table of Contents

“For commuters, the best front light is the very bright rechargeable lamp.”
Ken Kifer, Ken
Kifer’s Bike Pages

Ken Kifer was killed, while riding
his bicycle, by a drunk driver, on September 14, 2003. His wisdom about cycling
lives on.

“With vastly more light available, night bicycling is qualitatively far safer. The road can
be lit
both further ahead and, even more important, far more brightly to the sides of the bicycle.”
Marty Goodman, Writing about the CatEye’s Stadium Bicycle Light,
in History of Electric Lighting Technology


Not everyone can afford to buy a commercially
manufactured, very bright rechargeable lighting system, which Ken Kifer
accurately describes as the best light for commuters. While prices have come
down, a rechargeable lighting system is still over $100 when you add in a
good tail light.

This site
describes how to build a high performance, rechargeable.
lighting system without spending a lot of money. You can spend as little as $40
to construct a system, complete with a sealed beam headlamp, xenon strobe tail
light, rechargeable battery, and charger.

All components are available from retail or
mail-order stores. I don’t sell anything, this is purely an informational site.
This site contains my informed opinions, as well as the views of other groups
and individuals. There are many different solutions for bicycle lighting that
meet the criteria of “seeing and being seen,” and there are many solutions that
do not meet these criteria. Choose wisely and use common sense.

You don’t have to spend hundreds of dollars for
an adequate lighting system. A lighting system is not rocket science, it’s
basically connecting a battery to some lamps, through some switches. The challenge is in sourcing the
proper components and mounting them to the bicycle in a secure and reliable

HID bicycle lights, which cost at least $400 for a
commercial system, are now also available to cyclists wanting to build their own
systems, with all-in-one (internal ballast)

13W HID headlights available for $115
. Yeah, that’s expensive, but it’s
less than the 2 watt LED lamp used on dynamo systems! You can construct a simple
HID system for well under $200.

Not Rocket Science!

This site evolved from a set of plans I wrote back
in the 1980’s for a 78WH lighting system. I also had a side business manufacturing and selling
lighting systems for a while, but it was too much work for too little money.
These systems were sold with a choice of three headlights, 1) a 55W
automobile driving light with an H3 quartz-halogen bulb, 2) a 35W automotive
driving light with a bayonet incandescent bulb, and 3) a 14W sealed beam. From time to
time I would get e-mails asking for these plans; I resurrected them from their Wordstar DOS format, updated them, and put them on a web site.

What About Generator (Dynamo)
powered lights?
High power (relatively speaking) dynamo
powered lights will cost you over $350 in the U.S. (6 watt dynamo plus front and
rear lamp). As even the U.S. distributor for Busch and Muller concedes
(regarding dynamo systems), “they are not as bright as the high end high power
battery systems.” A debate rages on whether or not the 3W dynamo systems are
“bright enough,” but other than a few die-hard dynamo zealots, all the experts
agree that a 2.4-3W headlight is not sufficient for safe riding.

Location Makes a Difference

In the periodic “lighting wars,”
advocates of dynamo lights will inevitably cite Amsterdam, or other
cycle-friendly cities, as examples of why bright lights are unnecessary. Using
glib comments such as ‘dark is the same here as there,’ or ‘the laws of physics
don’t change between localities,’ they fail to look at the big picture and fail
to understand the differences of demographics, politics, education, and history.

Some of the reasons that location
makes a difference are as follows (not all reasons apply to all locations of

  • Strength
    in Numbers. The more people cycling the safer the cycling environment, and
    the better behaved the drivers. The whole concept behind Critical Mass is
    Strength in Numbers

  • Speed.
    Look at the speed of bicycle commuters in various countries. In Amsterdam
    and Beijing, the average speed is about one-third of that of the typical
    U.S. commuter. It can be maddening to be riding that slow if you’re not used
    to it, but you have to go with the flow. Low power lights are more
    acceptable at very low speeds. As Forrester writes: “The maximum safe
    speed for Dutch voonerven has been given as 8 mph. Average travel speeds on
    Dutch urban bikepaths are universally described as very slow, probably below
    10 mph. On the other hand, speeds of American bicycle commuters, now easily
    measured with electronic speedometers, typically are in the 16-22 mph range.
    Dutch cyclists tolerate their low speeds for two reasons: travel times are
    not great because they travel short distances and motoring is so
    inconvenient that it would probably take longer. American cyclists would not
    tolerate Dutch speeds because of the longer distances they must travel. The
    facilities, traffic rules and speed-controlling attitudes that are
    acceptable to one nation are obviously unacceptable to another.”

  • Street
    lighting. Street lighting in European cities is usually very good. In the
    suburban environment of the U.S., street lighting is often poor or
    non-existent. For example, one street I used to ride on fairly often was El
    Camino Real from Palo Alto to Redwood City. For whatever reason, Atherton
    (one of the cities along El Camino Real) decided that they did not want
    their section of this busy thoroughfare to have any street lighting. To
    safely ride through Atherton it is necessary to have bright lights.

  • Facilities: Countries, such as the Netherlands, have extensive systems of
    bicycle paths and bicycle lanes to separate bicycles from the rest of

  • Driver
    Education. In the U.S., the driving test is perfunctory, unlike in countries
    like the U.K. and Scandinavian countries. In the U.S., it is vitally
    important that, as a cyclist, you ride more defensively, part of which
    includes using bright lights at night.

  • Driver
    Experience. Many parts of the U.S. have a disproportionately high number of
    adult drivers that learned to drive late in life, and that are from
    countries where the relationship between bicycles, vehicles, and pedestrians
    is based on size and intimidation, where drivers believe that they always
    have the right of way. Visit China, Taiwan, or India for verification!

  • Social
    attitudes. As Forrester writes,

    The different physical and
    economic histories produced the expected social attitudes. In America, since
    cars were obviously the most convenient means of transportation, the person
    who did not drive was considered a failure unable to afford a car. Americans
    did not possess the European tradition of genteel poverty. In American eyes,
    those who cycled were economic and social failures. While there was
    considerable class-consciousness about European cycling, as about all
    European social life, cycling still had sufficient utility in the cities and
    the country towns that cyclists were not automatically rejected by society,
    at least until recent decades.”

For a nice photo-essay on Amsterdam
bicycling see
. On the subject of the
pervasive use of dynamo lights, the author writes,
bicycle in Amsterdam is outfitted with a dynamo powered head lamp, where the
rider has to pump extra super hard and the head lamp shines dimly. If you are
younger than 35 years old, you probably have never seen one of these in the USA,
we have very bright headlamps for bicycles that add much less weight and do not
increase resistance. I haven’t seen a single dynamo powered bicycle in San
Francisco in over 20 years. Once I saw a “Simpsons
(animated comedy) episode where Bart turned on his dynamo bicycle headlamp and
could barely make forward progress-> in the USA these dynamo powered headlamps
are considered a JOKE, but almost a quarter million bicycles in Amsterdam all
have them.”


Making Your Presence Known

Riding safely at night (and even in the daytime)
means doing everything possible, within reason, to make yourself visible and
your presence known. Your life depends on being visible to vehicles. This is the
U.S. we’re talking about here, complete with lunatic drivers (both drunk and
sober); elderly drivers who should not be driving in the daytime, let alone at
night; and inexperienced drivers (young and old) who may look out for other
vehicles, but don’t look for pedestrians and cyclists very carefully, even in
the daytime. It’s a place where motorists that engage in serial red light
running, and that never stop for pedestrians in crosswalks, will complain
bitterly about a cyclist not coming to a complete stop at a stop sign.

Except for yahoos and drunks, most
motorists don’t intend to behave badly around bicycles–they are simply
clueless. Even non-clueless motorists, including myself, get very upset when I have a close call with a
bicyclist that is not visible at night. On the other hand, motorist behavior when they see a highly visible
bicycle is truly amazing. They don’t crowd you, they don’t cut you off, and approaching from the rear they arc around you giving you plenty of room.

Stadium Lights

Advocates of inadequate lighting, that are unable to present coherent reasons for
their position, will often claim that I am advocating that
bicyclists install desk lamps, stadium lights, nuclear reactors, etc. on their bicycles. Such an exaggeration shows just how weak the position the poor light advocates is. No one is saying that you should tow around a car battery that
powers dual 130 watt off-road driving lights. There are both commercial and
home-made systems that will make you very visible without going to ridiculous
extremes. Cyclists that have gotten away with inadequate lights for years are
fond of pointing to themselves as proof that in fact their equipment is just
fine, but of course all it proves is that they’ve been lucky so far.

Discover the Pleasure and Safety of Night Cycling
Many cyclists are discovering the enjoyment of night and early morning
riding. The weather is cooler, the traffic is much lighter, and a ride before or after work is a great way to start the day or unwind after a grueling day.
I especially enjoy a post-dinner ride to a coffee house because I can pretend that I’m in Amsterdam or
Taipei instead of San Jose.

In the 1980’s I used to lead all night bicycle rides for
a local bicycle club (Western Wheelers). These rides started at 2:00 a.m.. We rode throughout Silicon
Valley with no problems other than one drunk coming out their house and hurling
a beer bottle at us (he missed). I also led the same type of ride up in San
Francisco, riding through North Beach (including Lombard Street), Chinatown
(with a 3:30 a.m. restaurant stop), downtown (via the Stockton tunnel),
Fisherman’s Wharf, Golden Gate Park, and across the Golden Gate Bridge. It was
wonderful riding through San Francisco on virtually traffic-free streets (if
anything, people were scared of us!). Take back the night!


Nothing can eliminate the dangers inherent in
riding a bicycle. No lighting system can completely eliminate the dangers
inherent in bicycle riding at night. In no way do I intend to imply that use of
a bicycle lighting system built according to these instructions will reduce or
eliminate the dangers inherent in bicycle riding at night. Bicycling can be a
dangerous activity regardless of the time of day due to unpredictable,
inattentive drivers, as well as by poor cyclists . I assume no liability for
accidents, death, or injuries incurred as a result of using a a system built
according to these instructions. You should take following precautions to lessen
the danger:

  • Check state and local laws regarding the use
    of high wattage lights on bicycles, and regarding flashing strobes (as well
    as legal colors). In most states, flashing red lights (i.e. LED blinkers)
    are not legal, but flashing amber lights are fine. Most LED blinkers can be
    set to steady-on if law enforcement objects to the flashing mode.

  • Always carry spare batteries, bulbs, fuses,
    and the tools and knowledge to install them.

  • Carry a legal back-up lighting system in case
    your primary system fails. Check state laws regarding bicycle lighting
    requirements to ensure that the back-up system is adequate.

  • Ensure that the system is properly attached to
    the bicycle. Check mounting brackets, Velcro straps, wiring harnesses, and
    rear rack attachment hardware every time you ride. This is especially
    important because if the system fell off, or if the wiring harnesses became
    tangled in the spokes, it could cause you to crash. 

  • Check wiring harnesses for fraying or
    breakage. A short in a wiring harness will cause the fuse in the system unit
    to blow. 

  • Ride safely and obey all traffic laws. Ride
    defensively. Anticipate the actions of inexperienced, poor, and reckless

  • Wear reflective clothing. 

  • Properly wear an ANSI or Snell approved
    bicycle helmet.

  • Install a loud horn on your
    bicycle (audible devices are required by law in some places)

  • Make sure that your bicycle is in safe riding

versus Being Seen
There are two things you have to
consider when riding at night:

     1. Seeing the road

     2. Being seen by motor vehicles (as well as
pedestrians and other cyclists)

Being Seen
On streets that are well lit you need
lights that will make you visible. The best lights for this are xenon strobes. You can
put a red or amber xenon strobe on the back of your bike and a clear xenon
strobe on the front. You’ll still need a low wattage front headlight to remain
legal. A xenon strobe is similar to what’s used in a camera flash. An electronic
circuit charges a to a high voltage and then discharges it through a xenon tube.
Xenon lights are incredibly bright considering their relatively low current
draw. Xenon strobes are visible in areas with a lot of ambient light, and are
even visible in the daytime. Avoid low-intensity LED blinkers which are cute, but not very
visible except in total darkness.

On darker streets you need to be able to see the road in front of you. How
far you need to see depends partly on how fast you ride. For quartz-halogen
lamps, a good rule of thumb is a minimum of 10 watts, then an additional watt
for every mph over 10 mph. So at 20 mph you should have a minimum of 20 watts.
To reduce the amount of watt-hours you have to carry around, it is a good idea
to have two headlamps, and select either or both depending on your needs. This
is why commercial lighting systems often offer dual lamp systems, i.e. one 20
watt and one 5 or 10 watt headlamp, or two 10 watt headlamps.

Myths and Facts About High Quality Rechargeable Lighting Systems

I added this section because there are
so many myths being promulgated by individuals who are very much against the
use of bright, high
quality bicycle lighting systems (because they don’t use them, and think
everyone should live their lives the same way they do). As these people create more myths, I’ll
add to this section. Some of these people are fairly desperate, and make all
sorts of amusing accusations, and I include these in this section for your

Myths and Facts

Optics Debate
(and field of view)

Headlights intended for use with dynamo systems are
designed to work with the lower intensity 2.4-3.0 watt lamp bulbs. They use a
tightly focused beam that illuminates directly in front of the bicycle, but that
doesn’t provide much illumination to either side.

The Optics Debate

You can equip your bicycle with very good quality
lighting without spending a fortune. In some cases this may require that you do
a bit of work to connect a battery to a light through a switch, but it’s not
rocket science. This section looks at how much you’ll have to spend.

Cost Section

As an electronics hobbyist for most of
my life, and an electrical engineer who frequently is involved in prototyping, I
am very familiar with component sourcing. Non-engineer types often have no idea
where to buy the parts at reasonable prices and are shocked when they see how
much parts cost at places like Radio Shack or Fry’s. This section tells you
where to buy components.

Sourcing Section

Watts Versus Lumens
Technically, a watt is a unit of power, not
light. Lumens are a better unit to use because the lumen is weighted to how the
human eye responds to light.
This table compares different
lamps, their power consumption in watts, and their light power (luminous flux)
in lumens. This section looks at illumination.

Watts Versus


While each person’s needs may vary, here are some suggestions for lighting

Buy one set of Optronics MR16 based driving
lights, one 10W narrow flood MR16 lamp, one 20W flood MR16 lamp, a 5AH sealed lead-acid
battery, a dual-rate 1000mAH charger, a 12 volt Xenon strobe tail light, a frame bag for
the batteries, connectors, a plastic box for the switches, and three switches.
As an alternative to the MR16 lights, buy two 14W sealed beams. I prefer the
latter solution but it is a bit more work to construct.

For a budget system, use one 5AH battery, one 14W
sealed beam, one xenon strobe, and one dual rate charger. You can construct
something for less than $50.

For an HID system, buy a TrailTech
HID (flood), a 5AH sealed lead-acid battery, a dual-rate 1000mAH charger, a 12
volt Xenon strobe tail light, a frame bag for the batteries, connectors, a
plastic box for the switches, and three switches.

You will have to figure out a place for the
battery pack and a way to mount the headlights to the bicycle. I prefer mounting
the lights to the front reflector bracket (use a rectangle of aluminum or wood
for two lights, but for one light you can mount it directly to the bracket).
The batteries can be placed in a frame bag, seat bag, or rack-top bag.

I am less enthusiastic about NiMH systems because
of the need to parallel AA battery packs in order to provide sufficient current
to the lamps if going over 16 watts or so. Using C or D cells will work, but is
very expensive because C & D cells are much more expensive per AH then AA
cells. Also, it is rather a pain to build the AA packs with a battery holder due
to the tiny solder tabs on the holders. While parallel AA packs solve the cost
and current issue, you have to charge the packs separately which is a pain if
you want to charge your batteries overnight (unless you buy two chargers).

This section looks at selecting headlights for a
home-brew lighting system.

Headlights Section

Mounting to Bicycle

This section looks at methods of attaching
headlights to the bicycle. This has traditionally been a source of frustration
to people building their own systems. You want to mount the headlight securely
and neatly. No hose clamps (jubilee clamps) or U bolts!

Headlight Mounting Section

This section looks at selecting tail lights for a
home-brew lighting system. The few good LED flashers are very expensive, but an
excellent xenon flasher can be purchased for less than $10.

Taillights Section

12 Volt or 6

This section discusses the trade-offs between a 12
volt system and a 6 volt system. A 12 volt system is usually the better choice.

12 Volt or 6 Volt Section


There are many types and capacities of batteries to choose from,
with various trade-offs of weight, cost, and size.

Batteries Section

This section looks at switches and enclosures.
Choose carefully to avoid a kludgey, unreliable system.

Switches Section

Use connectors to make your system modular. The
battery, headlight, and tail light can all be connectorized. This section
advises on the best connectors.

Connectors Section

You’re going to have to do some soldering in order
to get reliable connections.

Soldering Section

Run Time
Calculating run-time is complex, because battery
ratings are not always as they appear. Sealed Lead Acid (SLA) batteries have
amp-hour ratings that are based on very low current discharger rates, and at
higher rates the ratings are less.

Run Time Section

This section looks at various types of battery

Chargers Section

Can Build This


of this system should only be undertaken by a reasonably well mechanically
inclined person. You should be able to solder, know your
way around Home Depot and Radio Shack, and know how to use drills, Xacto knives,
Dremel tools, heat guns, etc..

(note that there are multiple possible sources for most of these items)

Parts List Section

Electrical and Mechanical

This section details the construction of a system.

Electrical and Mechanical
Construction Section


No, this doesn’t mean lights for riding in reverse.
It means that you should have a back up lighting in case your primary system
fails for some reason. For a headlight, this can be as simple as a TwoFish
LockBlock with a Mini-Mag-Lite. For a taillight, an LED flasher in addition to a
xenon strobe, is a good idea.

Back-Up Lighting Section

Dynamo Powered Lights

The main purpose of this web site is to
explain how to construct a high performance battery powered lighting system.
I’ve gotten some not-so-nice e-mails, and seen some bizarre-logic Usenet posts,
that promote dynamo powered bicycle lighting systems. These e-mails and posts
also dispute the need for the greater illumination provided by higher power
lights. I decided to add this section on dynamo powered lights, so the reader
can get an unbiased evaluation of the pros and cons of dynamo powered lights.

Dynamo Lights Section

Flashlight Type

Decades ago, a flashlight on the handlebars was a
common type of bicycle light. Ironically, with the advent of new flashlights
with very bright Cree LEDs, along with improved methods of mounting the light to
the handlebars, this type of light is making a comeback. A Cree LED flashlight
that costs $30, has equivalent light output to a bicycle light costing five
times as much, and far exceeds the capability of most dynamo powered lights.
There are many discussions of these types of lights on
Candlepower Forums

Flashlight Type Lights Section

with Built-In Lights

A few commute bicycles now come with integral dynamo
hubs, and front and rear lights. This section looks at this option.

Bicycles with
Built-In Lights Section

HID Lights
HID lights are the best bicycle
lights in terms of brightness and efficiency. Prices have fallen and you can now
put together an HID system for less than the cost of a good dynamo based system.
However you can spend a fortune on HID lights if you really want to, as
evidenced by the German made Busch & Müller “Big Bang” (see
) which sells in the U.S.
for $953 (plus $3 for a wall plug adapter). I was all set to buy one, but I
didn’t want to pay for the wall plug adapter (c’mon Peter, you really could
throw in a 50¢ plug adapter for free).

HID Section


LED lights offer long run time, but fall a little short in the
brightness department.

.LED Section


Flash Flags help visibility.

Flags Section

we’ve discussed lighting, now what about sound? The prepared and properly
equipped bicyclist has both a
polite bell and an obnoxiously loud horn.

Sound Section

Cell Phone

As long as you have a 12 volt system, you may as
well keep your phone charged up.

Phone Charging Section

over to
The RBRC is a non-profit, public service organization created (and funded) by the rechargeable power industry to promote the recycling of portable rechargeable batteries. As part of the program, all components of the products shipped back for recycling are broken down and re-used: for instance, the cadmium is used to make new batteries; the nickel and iron are used for new stainless steel products.

Wear a

While I am not a helmet zealot, wearing a helmet is
a good idea.

Helmet Section

While proper lighting is important
for commuters, proper caffeineation is also
crucial. Please visit Bicycle
Coffee Systems
for information on how to keep properly caffeinated
during your ride. A major update to Bicycle
Coffee Systems
occurred in March 2005.

Caffeination Section

Commute Bicycles

If you are looking for the proper
bicycle on which to commute, please visit
Don’t depend on the generator lighting systems used on these bicycles.


It is not difficult to construct a
high performance bicycle lighting system, and it’s much cheaper to build your own
as long as you are reasonably mechanically inclined.

to other Bicycle Lighting Sites

I have explained what I do, and what I believe is
best. Get some other views on the subject of bicycle lighting at some of these
other sites.

Links Section

About the Author

Steven M. Scharf is one of Earth’s leading experts on bicycle lighting. An electrical engineer by trade, he enjoys cycling and
designing lighting systems. He lives in Silicon Valley and works for a small semiconductor company. He has bicycled all over the world, including Canada, Russia, Thailand, Japan, Taiwan, and China. See a list of his bicycle related web sites at

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