How to understand Motorcycle Lighting...
Three Sections:
Basic Lighting Theory - How light is generated by different types of lighting.
FAQ/Q&A - answers to some of your motorcycle lighting questions.
What You Really Need To Know - to upgrade your motorcycle lighting effectively (or the least you should read).
Lighting: Basic Theory 1101
METHODS FOR GENERATING LIGHT:
Incandescent light:
the traditional light
bulb. Used in blinkers, old headlights, cheap home bulbs (the type you
get 4/$2 at the supermarket). A filament, when fed power, vibrates at a
rate to give off excited electrons sits inside a vacuum. Normally
failure occurs when the filament finally has vibrated so long that it
breaks or burns (thus the pop of a light bulb when it burns out).
Upside: Cheap.
Downside: Low efficiency.
Halogen lights:
pretty similar to the
above traditional incandescent light, but because the space around the
filament is filled with over-pressurized halogen gas (halide gas - mix
of an inert gas with a halide buffer), the filament can be designed to
run hotter, thus producing more light for the same amount of power
without burning out. Halogen also interacts with tungsten filaments in a
special way to redeposit vaporized tungsten back onto the filament,
which extends the filament's life. Because Halogen bulbs run at higher
temperatures, halogen bulbs are surrounded by quart or
high-quartz-content glass, which can handle the heat without breaking.
Quartz on the other hand, will shatter or lose structural integrity from
moisture (especially oils) and salts, and thus you are told to never
touch them with your hands (using a clean rag or paper towel instead to
act as a barrier for the oils in your skin -- if you do get any on the
bulb, wipe it with a paper towel and rubbing alcohol to remove both the
oils and salts). Xenon is another fire-retardant gas, and it works
similarly to halogen (and is often mixed with halogen in filament bulb
designs).
Upside: Only slightly more expensive than traditional incandescent with
a substancial increase in light produced.
Downsides: Quartz doesn't like oil, water; runs hotter than incandescent bulbs.
One Word of Caution:
The wiring for your bulbs is rated at a maximum power draw without over heating -- the same power draw as is specified by your owner's manual in terms of bulb wattage. If you decide you want to go with brighter lights (brighter by virtue of drawing more electricity), such as a 80/110 bulb instead of the stock 55/60, you need to replacing the wiring and the relays to the headlights to handle the extra power without overloading the wires and the relay(s), effectively overheating them -- because having your bike catch on fire sucks.
Fluorescent lights:
the gas contained in
the bulb or tube is a special formulation which supports a "rest state"
and an "excited state". The excited state occurs by loading up the gas
with extra electrons, and then when it reverts to it's rest state, the
extra energy in those electrons are shed in the form of light. There is
no filament, but instead a ballister, an electronic part designed to
convert the power from the local draw into a high voltage state required
to lift the gas into it's excited state, and does so many times a second
(so fast that you can't see the blinking, at least if it's working
right). Very cost effective, but space consuming.
Upside: Very efficient, low temperature.
Downside: Requires large volumes to produce good quantities of light & difficult to focus, thus impractical for motorcycles.
Neon Lights:
Just like fluorescent lights,
except the gas is neon (or some mix with neon as the basis), which
causes the excited state to shed it's power in a specific light range
(i.e. - color, such as red or blue or green, etc).
Upside: Very efficient, low temperature.
Downside: Requires large volumes to produce good quantities of light & difficult to focus, thus impractical for motorcycles.
Light Emitting Diode (LED):
basically a
very tiny, weak laser of a sort. LED's produce very intense light in
very narrow wavelengths, but do not produce large amounts of light
compared to the other technologies listed here. A current
high-efficiency LED light will produce about two lumens (compared to
something like 1500 lumens for a typical headlight bulb on low-beam).
This means they are not very useful at this point for lighting the way
for you. On the other hand, LED's are very useful for "See Me, Notice
Me" applications, such as brake lights, blinkers, daytime running lights
and other uses where they are to be spotted from a distance by a viewer
in direct line of sight.
Upside: Very efficient, low temperature (individually).
Downside: small quantity of light output, useable focus is poor.
Arc lights (limelight, sodium lights):
Yet another way of making light, one that isn't used very much any more
except in parking lot and highway lighting. Again, there is no filament
as such, but instead an electric arc jumps between two points, and that
arc is bright enough to light up everything around it. The color nature
of the arc is controlled in part by chemicals the electricity is jumping
(arching) between.
Upside: Immense amounts of light.
Downside: requires large physical size, thus impractical for motorcycles.
High Intensity Discharge (HIDs):
True HIDs are a
variation between the fluorescent/neon concept, and the arc-light concept. Here,
an electrical arc jumps through a specific gas (generally xenon) to produce a plasma
state of the gas itself (the 4th state of matter, after solid, liquid and gas),
which results in an exceptionally bright light. Because of the gas or
gas-mixture used, the resultant plasma produces a bright white to blue-white light, depending
on the rated temperature of the gas-mixture. To
get the electricity to excite the gas into this plasma state in this set-up, the
power is stepped up to a very, very high level (extremely high voltages, typically
as alternating current). Actually, there are two power steps, one to jump-start
the plasma state (the initial surge), and one to maintain it once it's
happening. When I first wrote this webpage, the equipment to create a true HID
ran from $500 to $4500 dollars -- per light -- including the projector lenses,
the arc chamber, the required electronics (capacitors, etc). As the HIDs became
more main-stream, prices dropped, and you can now find bolt-on external HIDs in
very small sizes at far lower prices than before. There are conversion kits out
there designed to use the existing bulb fitments and reflectors with a
substitute bulb that is a true HID; these run in the $40 to $300 range (as of March 08),
depending on manufacturer, quality of the electronics, whether the bulbs contain servo's or
secondary filaments for high-beam use, et cetera.
There's also the two-beam issue: no HID on the market has both high and low beams as
true HIDs in a single bulb (can't engineer two arc chambers that overlap, can't shrink
the arc-chamber further economically and still get the same power-output). HIDs claiming
they do both high and low-beam add a standard halogen filament bulb into the design to
give you the secondary beam (usually the high-beam); or there has to be a servo motor to
actually reaim the bulb itself by moving the bulb (by the base; Bosch did these for a while), or by moving a metal
shade outside the bulb (common, more cost-effective to manufacture). These servo-based HIDS
are commonly referred to as Bixenon HIDs, because both high- and low-beam are HID-based light.
Upside: Immense amounts of high-contrast light without excessive power-draw.
Downsides:
Cost to acquire;
Temperature concerns when modifying halogen designs;
placement of ballasts & their heat (some run hotter than others);
No high/low beam true HID bulbs (in a single bulb) available.
Buyer Beware:
Note that halogen and xenon-based filament lights can be filtered to give a "HID" appearance in the light frequencies they cast, but they still only produce the amount of light that a halogen (or xenon+filament) light would produce, less whatever the filter subtracts. This is a far shot from the quantity of light which is produced by a true HID. Furthermore, because filtering removes some of the useable light, such HID-look filament-based replacements actually produce less useable light than the equivalent halogen-filament design.
Buyer Beware:
True Halogen bulbs come at a Kelvin-rated temperature, typically between 4,000°K and 12,000°K. Bright sunlight (daylight, noon) is approximately 5,500°K, and is what your eyes are atuned to best utilize the light from by virtue of millions of years of evolution (or intelligent design if you prefer that) -- buying 8,000°K and higher bulbs will give you both shorter bulb life AND less useable light in terms of what your eyes can see.
Carbon Nano-tube filament bulbs:
Still in the
development phase, but prototypes have been shown. Expect 2009-2010 before the
first ones make it into a motorcycle-compatible bulb. Basically the same as an
incandenscent bulb, but the tungsten filament gets replaced with a carbon
nanotube filament instead, resulting in more light per watt, and lower voltage
requirements to get it to the initial glow. Lifespan concerns in mobile
applications are still being addressed, as this technology is still in the lab.
See related story: Physics Web: Nanobulbs make
their debut
Upside: Better lighting per watt at low voltages.
Downside: Not available yet, may not turn out to be practical for vehicles due
to vibrations & shocks.
FAQ - Q&A:
You talk about excess changing capacity of the motorcycle. What do you mean by that?
Every motorcycle with a battery and alternator (or generator) produces
some amount of electricity (if working correctly). If we take everything
on a motorcycle or vehicle that consumes electricity while the
bike/vehicle is running (headlights, blinkers, horn, coils & spark
plugs, CDI, et cetera) and add it together, we arrive at some amount of
electricity required (we'll call this consumption level the Baseline Draw for
our purposes). The electrical system of all modern motorcycles is
designed to exceed the baseline draw by some percentage (at least by 5k RPM), to
ensure that the battery stays charged up, and that the battery recovers
whatever power was consumed during starting the bike. For our purposes
in explaining these concepts, we'll call the whatever the bike's
electrical system produces above required the baseline draw the
Excess Charging Capacity.
Different kinds of bikes come with different baseline draws and
differing degrees of excess charging capacity. Pure sports bikes (like
the Suzuki GSXR series, or the Honda 954RR) are usually built with
minimized baseline draws, and minimum excess charging capacities, to
help keep the weight of the bike down (less power moving around means
they can use a smaller battery, a smaller alternator or generator, and thinner
wires, all of which reduce the total weight of the bike).
Heavy sports-tourers (such as the Honda Gold Wing, BMW K1200 series) and
upper/mid-class sports-tourers (such as the Honda ST1300 and the Yamaha
FRJ1300) are designed by their manufacturers to inherently produce
higher amounts of excess charging capacity, because the riders of these
bikes are expected by the manufacturers to add on additional
power-drawing equipment beyond that supplied with the bike (such as
heated hand grips, radar detectors, radio & CD players, extra lighting,
et cetera).
Then there's everything else, which falls somewhere inbetween. Some
bikes have small excess charging capacities (8% to 25%), while others
have larger excess charging capacities (35% to 50%). Even within the
same year and model of bike, any two bikes can have significant
differences in the actual excess charging capacity due to variations in
the charging system (rectifier pack, voltage regulator), battery condition,
actual load.
Balancing Act:
It is important that you always leave your bike, even after adding equipment, with a degree of power surplus (excess charging capacity), so that you leave power to recharge the battery from negative draw conditions (such as starting the bike). We recommend at least a 10% excess be left after adding any equipment.
It is also important to note that many bikes run at a negative excess charging capacity at idle (such as the original Honda VFR700's), and only generate a positive excess above a certain RPM (such as 3500 RPM). The best way to be sure you are not drawing too heavily when you plan on adding lighting or other equipment is to add a gauge to inform you of the current status or measure it in testing, and to ensure that any additional equipment has a switch to turn it off.
I know in certain cars euro spec lights are better than DOT ones.
It's true that DOT lighting specifications (specifically for cars) often
result in lense and reflector designs that do not place as much of the
light into the sweet spot in front of the car that Euro-spec headlight
casings do. Do not confuse this with the lights producing less light --
they usually use the same bulb technology, and produce the same amount
of candle power or lumens -- but the DOT standard spreads that light out further,
reducing the harshness between the dark and the lighted areas, while the
Euro-specs (such as on our Audi) tend to form a harsher line between the
lit areas and the unlit areas. It's a matter of taste, where you drive
(urban vs. rural) and legalities.
To the best of my knowledge, Japanese and European-built motorcycles don't have
that same twin-market variation for acceptable focus designs. The only
difference I know of between the US and certain other motorcycle markets are in
the bulb wiring and bulbs. In Europe, pre-1997 motorcycles were only permitted
to light up one headlight bulb on low-beam (dim as it's called in the UK); the
EU changed that regulation for 98+ motorcycles, although some manufacturers
continued to ship single low-beam set-ups on their dual-headlight motorcycles to
specific European countries (Denmark comes to mind).
Another continental difference is power levels: E.G. - the UK market version of
the GSX600F & GSX750F (Katana) uses the same reflectors and lense system as the
US model, but the bulb spec (55+55 watts, instead of the US spec 60+55
watts).
As for HID lighting, who would want to put one on a bike anyway...
dont the ballasts weigh a lot for those things?
About 10 lbs at most, although weights on ballasts have been dropping in recent
years as manufacturers figure out how to make them deal with their own heat better (early
models had absolutely huge aluminum heat sinks). In the weight category for most sports-tourers (fairly heavy
bikes), it wouldn't make a noticeable difference. On the other hand, the
start-up surge for igniting the plasma reaction in the gas could be very
noticeable (very heavy draw initially, typically four times that of them operating).
As for why to put one on a bike -- the same obvious reasons they put them in
cars, both from the factory and aftermarket: 40%-100% more light delivered to the
road than the stock H4 halogen lights, in a brighter, higher-contrast lightwave
length (higher-contrast in terms of typical human sight, given a 6,000°K HID bulb vs. a
filament-based Halogen-filled bulb).
What about lights that are higher in luminescence (brighter), BUT more efficient, after all heating a wire for light isn't the best energy conversion to light.
Whatever it is, it needs to be:- Cheap enough for mass production;
- Put out light that's generally yellowish-white or white (good visibility to humans);
- Stand up to the environment in a car or motorcycle (vibration, temp, exposure); AND
- Be focusable and from a small source (the reason flourscent
technology isn't used in car lighting -- too big a volume requirement
for the amount of light needed, even though it's much more energy
efficient than halogen).
Could you plug in a bulb into a motorcycle that requires same or less
wattage but pumps out better luminescene [more lumens]?
If it drew the same or less electricity and ran at the same temperature
or lower, and connected to your existing power type (12-15V DC), created
light concentrated in the same spot as the current bulb (to maintain the
focus), you could use it with no problems. Does such a creature exist? I
doubt it, or else it would be in wide-spread use (of course, there are
high-efficiency xenon-halogen & true HID bulbs out there, but they are already in
wide-spread use).
What's the feasibility of LED Headlights at this point (like those shown on the Audi
prototype at the Geneva Auto Show)?
The following comments came from a technical conversation I had in late
November, 2003, with the US representative for Nachia, one of the
world's leading LED manufacturers. If a few years has passed since then,
this information may be technically outdated. In a nutshell: we are
currently at 3rd Generation LED-technology levels, and that's
insufficient. Maybe 5th generation Super-LED's will
make it happen.
Current market leader in the headlight LED game is Lumilux, who have gotten
there by increasing the physical dimensions of their LED's (but even
their product isn't ready for prime time by a long shot). It was
Lumilux's LED's that appeared in the Audi prototype at the Geneva Auto
Show. Still, they are a pipe dream at this stage as a headlight
technology, and hopes are pinned on developing a LED light engine in a 3
to 5 year horizon for an 8 year horizon of implementation (a light
engine is the back-end of a light assembly, to which auto manufacturers
design their casing and glass around). Apparently, LED's are moving
along at about half the rate of Moore's law, in terms of progression of
light quantity (lumens or candlepower) emitted, so they aren't
progressing as fast as some might hope.
The major problems for an effective headlight assembly are:
- Raw LED cost (preassembly) to do it effectively. We're talking a
projected cost of $400 - $1k or so for the number of lumens you need, without
addressing any of the other issues below.
- Focus. Hundreds of LED's, each having at least two focal points
(one at 90 degrees to the main focal point), provide a serious issue in
focusing the light effectively (much less focusing to the degree that it
would pass muster with DOT's requirements). On the other hand,
wide-spread LED's exist that are excellent for "See Me" requirements
(such as marker lights and daytime running lights).
- Heat generated. That many LED's clustered together would
generate a significant amount of heat. Since LED's run around 2-3 volts
for the brightest ones, even more heat would be generated by whatever is
used to step down the voltage and keep it at a stable level as the
bike's electrical system varies between 12.2 and 14.8 volts with the
RPM.
- Heat exposure. LED's are actually rather heat intolerant, and
one of the major issues against putting them in cars is the need to
ensure they do not get exposed to temps above 150 - 170° (F). This is a
design issue for the assembly design, and probably wouldn't be as much
of an issue for motorcycles because the headlights tend to be held
forward and away from the engines. Still problematic because of heat
coming off the oil/water radiator(s), but he didn't mention that.
- Compliance -- with DOT requirements for focus, lumens actively
put on the road, etc.
He did say there was a conference in the next few days (Friday or
Monday) in Southfield, Michigan for the major players in the industry
about the direction of LED headlight and daytime running light
technologies (GM, Ford, Chrysler, and possibly Harley will be
represented).
He also said that his firm was already working with one particular firm
that was trying to design an aftermarket bolt-on LED based headlight for
the off-road and Harley markets in particular, with the off-road market
as their first target (since no DOT requirements exist for off-road
vehicles); they have a projected 18 to 36 month time frame for getting
the off-road version out, and the street version after that (with a hint
that they weren't worrying about complying with DOT requirements even
for the street version at this point -- a disclaimer in the package
would be enough at this stage).
To be effective, what is really needed is a higher lumen to watt ratio
(for heat reasons), and a higher lumen to cost ratio (for economic
reasons).
LED UPDATE (Mar 08): we still haven't reach the point that LED's are viable for the light-engines of modern vehicles, but we're getting a whole lot closer. Lumilux was sucked up by Osram, and although their LED's are commonly used in many newer high-end vehicles for daylight visibility (i.e. - to make cars more visible), they are still not ready for prime-time as a headlight technology.
What you really need to know...
INCREASING THE LIGHT TO THE ROAD SURFACE:
You have five basic choices:
- Replace the stock bulb (E.G. - 55 watt draw on low beam/60 watt draw on high
beam, commonly written 55/60) with a bulb that draws the same current and yet
produces more light (Example: for 55/60 H4's, you could try the Sylvania
SilverStars or HELLA Part Number 8GJ 002 525-821, both of which are said to be a
55/60 draw with a +50 watt output efficiency, effectively producing the light of
a 105/110).
Short Term: No problems, more light.
Long Term: Runs somewhat hotter (temperature wise inside the casing), potentially resulting in earlier failure of the silver backing on the back of the reflector housing (say 15 years rather than 20 years).
End Result: More light now is more important, and if you have to replace the reflector in fifteen years of use instead of in twenty years, so what.
Final Analysis: Very Good choice.
- Replace the stock bulb (55/60) with a bulb that draws the more
current (say an 85/100 or a 100/110). Use the same wiring. This produces
more light and more heat.
Short Term: More light in the same place, fuses popping every so often, wires running at higher-than-rated loads and thus the wires start overheating. Sooner or later, the wiring or the bulb retainer melts, or the wire catches fire. Fuses are annoying in that they go out regularly too.
Long Term: Electrical nightmares (melted insulation, melted bulb retainers, wires getting glowingly hot, possible electrical fire, failed headlights and, rare, but does happen -- possible failed rectifier to the alternator). Melted insulation = unexpected shorts, which will kill the battery and/or rectifier pack, requiring replacement. Plus shorter life on the silver reflective coating on the headlight reflector (more watts = more heat, even with the same watt per lumen rating). Less of an issue if you only run short distances (the wires don't have as much time to heat up), but still asking for problems.
End Result: More light now, but this starts getting really costly, not to mention dangerous, since you have no clue when or how failure will occur, or when you can expect the wiring to fry.
Final Analysis: Really stupid choice.
- Replace the stock bulb (55/60) with a bulb that draws the more
current (say an 85/110 or a 100/110). Upgrade the wiring, fuse and relay
to be rated to handle the extra load plus a safety margin. This produces
more light and more heat. You can find premade kits to do this upgrade at
various vendors, including: SUVLight.com offerings.
You can also get the suitable parts at NAPA + Radio Shack,
and some better-stocked auto parts stores.
Short Term: No problems, A lot more light in exactly the same spot.
Long Term: Bit more draw on the charging system may cause failure of the battery and rectifier pack to the alternator at an accelerated rate on bikes with low excess power production, causing failure in 4 years rather than 5 (or 8 years rather than 9). Plus shorter life on the silver reflective coating on the headlight reflector, causing it to fail in 5 years rather than 20 years.
End Result: More light now, a somewhat accelerated wear schedule for certain components, but a worthwhile trade-off if you drive in unlit locations or have even a hint of night-blindness.
Final Analysis: Good choice for a serious upgrade.
- Leave the stock bulb (55/60) and wiring alone. Add additional
lighting in the form of added driving lights (Halogen, Xenon or true HID) mounted to the underside of
the center of the fairing, to a mounting bar, or to the forks. Seriously consider
also mounting a charging/discharging anameter gauge in sight.
Short Term: As long as you don't exceed your excess charging capacity, no problems, about the same useable light, but with a much bigger area illuminated.
Long Term: Slightly higher probability of rectifier pack and/or alternator failure, plus shorter battery life expectancy by about 15%.
End Result: More light now is more important, and if you have to replace the battery or rectifier in four years of use instead of in five years (or eight instead of ten), so what. Final Analysis: Good choice for a serious upgrade.
- Replace the stock bulb (55/60) with a HID replacement, and wire in
thicker wiring to support the extra draw when the HID first fires up.
Short Term: Make sure you consider the high-beam/low-beam issue before ordering, and wire in some heavier-duty wire to handle the high-draw load for when the power-packs first fire up the arc in the bulbs (draws about four times the regular draw to initiate the arc). Once you've got those resolved, great light on the road.
Long Term: Aside from the heat produced by the bulb and the power pack, no draw backs.
End Result: Quite a lot more light now, with few drawbacks if your bike has the space to store the ballast system in a dry location.
Final Analysis: Great choice for a serious upgrade as long as you buy wisely.
To make these choices a little bit clearer:
Metal vibrates when electricity passes through it. Vibration always
turns into heat over time (natural energy-state decay). The thicker the
metal strand(s), the greater the heat sink to suck up extra heat, the
more surface area to dissipate the heat, and the more dampening of
vibration (by virtue of more mass), thus the more electricity it can
carry without reaching a significantly raised temperature. If the wire gets
too hot, the insulation will smolder and catch fire, igniting the bike's plastics & fuel in
a worst-case scenario (been there, seen that).
All wires are rated for a specific current load at an ambient temp (you
can look this up for yourself). Also note that automotive grade wiring uses multi-strand
wires to handle flexing and engine-related vibration better, so this
reduces the load capacity (the inherently higher temperatures around the
engine compartment also reduce the effective rating).
There's a really cool voltage drop calculator on
the PowerStream.com wire size webpage -- very quick & easy way to see why you might want to
use heavier wire (aside from heat/fire issues). There's also a great Wire
Parameter Calculator here that lets you factor in temperature in the engine compartment to come up with maximum amperage
across a wire.
Personally, I always wire with the next lower standard AWG over
what's called for just as added safety margin (i.e. - calls for 16 AWG,
use 14. Calls for 14, use 12. Etc.); in motorcycle engine-areas, drop two standard
sizes to offset the engine heat.
As for the fuse: fuses are, in essence, thinner wire (that will overheat
& break earlier by virtue of it's thinness), which is designed to give
before the wire it's protecting gets overheated.
Now, given that, figure that motorcycle manufacturers use the thinnest
wiring they can get away with usually, for two reasons: cost (vs.
profit for the manufacturer) and to help keep the weight of the motorcycle down. So, if you
draw more power, replace the wiring for the item doing the heavier draw
to match it's needs. And replace the relays too, because they too carry
rated specs and can have similar problems (again, they are usually rated
for the expected load plus a small safety factor and not a significantly
higher load).
Hope that makes it all clear. Base the wiring on the load...
