Part 2: The Power and the Glory (or Batteries and Lights)
In the first part of our series, we got you in touch with the darker side of your riding. In this, the second part of the Fly By Night series, we're going to give you the low-down on the two most important components of any serious night-riding light system: the battery and the bulb.
There are a lot of different choices out there for light set-ups, with plenty of variations and choices for the exact kind of characteristics you're looking for, but the parts of the system that usually dictate the price and overall effectiveness of your lights do really just come down to the title of this segment.
Batteries:
The bottom line? The more you spend, the better the "energy density" (or "storage density") the battery will have. "Energy density" means how much power/energy a battery can store per kilogram. The higher the "energy density", the more power the battery can contain in a smaller/lighter space. So if you really need to save money or don't have much to spend, you can still have a half-decent light-setup…. Just be prepared to be lugging a heavy brick of a battery around with you, and try to keep your night rides relatively short. But if you are even half serious about having some fun in the dark, just remind yourself that investing more at the beginning in your battery, will mean a long lasting power supply that will be small enough for you not to think about when you're riding, letting you concentrate on more important things… like that step-down gap rapidly approaching at the end of the ladder-bridge your on…
Battery capacity of rechargeables is measured in mAh (milliamp hours) or Ah (ampere hours). For comparison, 1000mAh is equal to 1Ah. Obviously, the higher the capacity, the more energy the battery can hold and the longer your light can stay on in one sitting… But the greater the capacity, the longer it takes to recharge as well…
Energy Density is measured in watt-hours per kilogram (Wh/kg), and the higher the value of this, the higher the energy density.
The following batteries will be presented from least to most expensive:
Disposable alkaline
These are just your run-of-the-mill batteries you can buy from anywhere, whether they be AAA, AA, C, D or other variants. Easily and cheaply purchased as one-offs, they have a slow, predictable decline. In other words, their power drops off gradually as they get used up, making your light go dimmer and dimmer over time (as opposed to running at full output to the very end, then suddenly dropping off severely). Whether you consider this to be an advantage or disadvantage depends on the kind of person you are. Alkaline batteries won't suddenly surprise you by going "belly-up" abruptly, but from the moment you turn them on, they continually getting dimmer so you really only see full brightness at the very beginning of the battery's life They don't last long, they're bad for the environment, and they'll cost you a LOT in the long run. Generally, if you're serious about night riding, you shouldn't be buying a light that runs on these types of batteries.
Bottom Line - disposable alkaline
Duracell, Energizer, Eveready, etc…
Advantages:
cheap (in the short term)
readily accessible
steady, slow, predictable decline
energy eaten up quickly by high wattage bulbs
Disadvantages:
Low energy density (heavy)
expensive over the long run
bad for the environment
steady, slow, predictable decline
Sealed Lead Acid batteries
Similar to your typical car battery, the SLA battery is the solution for people who want to have high powered lights, but don't want to spend a lot of money on them. Cheap as chips, able to hold plenty of power and rechargeable, these batteries can power the brightest of lights, but at the cost of large size and heavy weight being that they have one of the worst storage densities out there. They come in a variety of sizes, but to run a 20 watt bulb for an hour, you'll probably need to lug around an SLA battery weighing close to a kilo. But, if you're the type of person whose bike weighs 20kgs or more, seriously… do you really care about weight anyway? Also needing to be stored charged, and can get damaged from over-charging or deep-discharging (running the battery down so it's COMPLETELY dead…), they're not exactly a low-maintenance battery. Very few companies sell light-systems powered by SLA batteries nowadays, but if you're looking to make your own system, and value savings over inconvenience… they're a good choice.
|
Bottom line - Sealed Lead Acid (SLA)
Like your car battery
About 200-500 charge cycles
Must be stored charged
Storage density: 30 Wh/kg
Advantages:
inexpensive
Disadvantages:
low-energy density (big/heavy)
heavy
susceptible to deep-discharge/overcharge, and low temperatures
stored uncharged can result in permanent damage (can even make them useless) |
 |
Nickel Cadmium (NiCad)
One of the most common battery systems out there, NiCads are a usually entry point for the battery choice in serious lighting systems made for bicycles. Hence when looking at the most affordable lighting system from many companies, you'll usually find that they're powered by NiCads. Unlike SLA's, the voltage coming from a NiCad is constant (as opposed to steadily decreasing), which means you'll get the full brightness of your light for the entirety of the battery's stored energy, until it's practically empty, at which point the output voltage drops sharply (your light will "yellow-off", or go dim VERY quickly…). As usual, the increased price of the NiCad over the SLA means a higher storage density, letting you carry more energy for the weight and size of your battery. Unfortunately, the cadmium inside NiCads is toxic, making them terrible for the environment, so if you do decide to purchase a system using a NiCad battery, make sure you're cautious with them and dispose of them properly.
Another one of the big drawbacks of NiCads is "memory". When some NiCads are recharged before they've run out of energy, they may remember at what point they were recharged and see that as the new empty point. In other words, if you have a NiCad that can store an hour's worth of light on the trails, but you only use half of it before recharging the battery again, the battery will think it only can store a half hour of light from now on, unless it's recharged early again, in which case it can drop even more. You can bring your battery back from this debilitating condition and recover the full capacity of your battery by doing a deep-discharge (running your battery past it's minimum working level) but this demands caution, since you can also permanently damage your battery doing this.
Manufacturers of NiCad batteries say they aren't plagued by the memory effect any more, but this hasn't been proved in practice yet.
All said, you can have a great life out of your NiCad battery if you follow the simple rule of operating your battery between extremes. Run the battery down to it's minimum working level EVERYTIME before charging it up to it's maximum level again. It might not need it, but better safe than sorry…
Bottom line: NiCads
25% lighter than SLAs
500-1000 recharge cycles
40-60 Wh/kg
Advantages:
Can handle deep discharges
Better at low temperatures than SLAs
Constant voltage through energy supply
Disadvantages:
Many NiCads are susceptible to the "memory" effect
Materials used in NiCad are very toxic and bad for the environment
Steep power-drop off when battery is almost empty |
 |
Nickel-Metal Hydride (NiMH)
Nickel-Metal Hydride (Ni-Mh) is the next step up from NiCads, with several advantages Most importantly, it's storage capacity is 50% more than NiCads (meaning it's 50% lighter for the same amount of energy), it has no toxic materials so it's much better for the environment when it comes to disposing of the battery, and it has no "memory" effect, meaning you can charge up your battery whenever you feel like it without any ill effects. Like NiCads, they output a constant voltage, dropping off severely when nearly empty (maximum light for the entire battery capacity, then "yellowing-off" suddenly…). NiMhs, however have less charge cycles before the battery is worn out (around 500), and have a higher self-discharge rate (they slowly lose battery power while just sitting there doing nothing) - as much as 5% of their energy per day, although more refined NiMh batteries coming out today are fixing this…
Bottom line: Nickel-Metal Hydride (NiMH)
similar to NiCads, but are up to 50% lighter
can handle any recharging at any point in their cycle
60-80 Wh/kg
Advantages:
Up to 50% lighter than NiCads
much better for the environment (much less toxic during recycling process)
Disadvantages:
lose charge faster other batteries (whether used or not - and should be topped up if stored for more than a week) |
 |
Lithium Ion (Li-Ion)
Lithium Ion (Li-Ion) batteries are the new king of the heap when it comes to night riding systems. Relatively new (they've only become available in the last few years), these batteries are about the lightest you'll be able to get with a lighting system, weighing about half the weight of a NiMh and don't suffer any "memory" effect. They are AWESOME. The disadvantage? Price. 40% more expensive than NiMh batteries and 300% more expensive than SLA's! But when you consider the amount of power you can store in a small, light Li-Ion battery, the idea of paying that much for up to 6 hours of bright light in a small, out of the way battery, the sting of the price isn't that bad…
Bottom line:Lithium IOn (Li-Ion)
50% lighter than NiMH
65% lighter than NiCads
80% lighter than SLAs
Storage density: 90-150 Wh/kg
Advantages:
Smallest, lightest option going
Disadvantages:
Most expensive (including expensive computer-controlled "smart" chargers for their sensitive batteries)
Bulbs
You've got several choices for the kind of bulbs that bike lights use. Generally, most high end systems use either halogen or HID bulbs. If you're going to be doing any kind of aggressive riding on the trails at night, you should stick with either one of these kinds of bulbs… not that you have much choice if you're buying a light system $100 or more… FYI, colour temperature defines the light's appearance ranging from "warm" to "cool". "Warm" means you have a yellowish light, whereas "cool" means the light is more white (and even slightly blue). Warm/yellow lights have a "friendlier" colour about them, whereas "cool" lights seem brighter and more closely resemble daylight.
Incandescent (inert filament) -
The simplest and cheapest of the light bulbs, this is the kind of bulb you'll find in your run-of-the-mill cheap torches and bike lights. Lousy output of light, these bulbs also use a lot of power for their inefficient design. Stay away. I only make a mention of these in case you see the term incandescent pop up and you don't know what it means. At least they're cheap to buy and easy to find.
Bottom line:
Colour temperature: warm (yellow light)
Advantages:
cheap
Disadvantages:
very inefficient (most of the energy given off as heat and not light)
not very bright
require lots of battery power
short bulb life
low colour temperature (yellowish light)
LED (light emitting diode) -
A surprising new player on the lighting scene is the ol' LED light. Once the realm of electronics and toys, the new generation of LED lights can put out an amazing ratio of light intensity to power drain, and although most lights using LEDs in the bike market today are tiny single bulb units more suited to alerting other people to your presence (like motorists or pedestrians) or close quarter repairs, some light companies are pushing the realms of what was thought possible for LED systems, by putting out multi-bulb high intensity LED lights that give amazing amounts of light, while being miserly on energy consumption.
All LEDs have the advantage of almost unlimited bulb light, and far less power drain than all other types of bulbs. The small, single bulb units can be powered by watch batteries and come in waterproof units no larger than a 50 cent coin, and weigh less than 50 grams, while the large multibulb units can give you enough light for riding, while pushing your battery life further than most other bulbs, all within a maintenance free package!
Bottom line:
Colour temperature: cool (white(slightly bluish) light (or a multitude of other colours, depending on the bulb colour))
Advantages:
ultra long life bulbs
very durable
unaffected by jarring shocks
efficient
Disadvantages:
not as powerful in output as other kinds of bulbs |
 |
Halogen (filament bulbs containing halogen gas)-
The most popular type of bulb, it has the best ratio of brightness to cost. The higher colour temperature means a whiter light than an incandescent, while the bulb life is much longer and it puts out a brighter light. The bulbs are also relatively easy to find and replace yourself. Although more efficient, halogens can still eat up battery power pretty quickly while getting fairly hot in the process…
Bottom line:
Colour temperature: Cooler (Yellowish-white light)
Advantages:
longer life
brighter
Disadvantages:
Still somewhat inefficient, and uses a lot of power |
 |
HID (High Intensity Discharge) -
Like the Li-Ion battery, these are the kings of the night. Ever see those cars driving along at night whose headlights seem to be bluish-white? And usually they're BMWs, Mercedes, or more expensive cars? Those are HID lights you're looking at. Their cool colour temperature means that the light they give off is a cool-bluish white, which closest resembles daylight. This obviously is the best for riding the trails at breakneck speed at night. The brightness of these lights can easily be up to three times brighter than a halogen that requires the same amount of power, and the bulb's life can last five times longer than your typical halogen bulb. Very efficient, these bulbs create the least amount of heat for the huge amount of light they put out. The disadvantages? Well, they actually need a "warm-up" period when first turned on (about 15 to 20 seconds) before they reach their full brightness, and when turned off, may need a cooling down period of several minutes before you can turn them on again. And of course, these are the most expensive option out there for bulbs. Not to mention, you probably won't be able to service them (such as change a bulb) yourself.
But if you have any doubts about HID, you simply have to see one of these lights in action to do it justice. Wow. If you can, try a comparison between a halogen and an HID… You'll see why HID lights usually come with the warning NOT to shine these things at oncoming cars, since there's a good chance you'll blind them…
Bottom line:
Colour temperature: Cool (Bluish-white light)
Advantages:
efficient (3 times more efficient than the best halogen lights)
light closest resembles daylight
longer battery life
bulbs last 3 to 5 times longer than halogens
Disadvantages:
price
warm up time (15-20 seconds before it reaches peak brightness)
repairs aren't easily or cheaply performed
Cool-down period needed after turning off the light before turning on again |
 |
Understanding measurements of a lights brightness:
Probably the biggest jungle to wander through when comparing lights, the power or the brightness of the light will be measured by one of these units, depending on the company who made the light system. When in doubt, don't be afraid to write to the company to ask for the measurement of the brightness of their lights in all the units. If they're a serious about their lighting systems, they should be able to provide you with the answer you want.
Candela (cd) -one unit of luminous (light) intensity. The term has been in use since the early days of lighting when a standard candle of a fixed size and composition was used as a basis for evaluating the intensity of other light sources. This unit is used in measuring headlight output.
Lux: another unit for rating the intensity of light
Lumen (lm): the illuminance (quantity of light or luminous flux) equal to the light given off by one candela.
Kelvin (K) - A basic unit of thermodynamic temperature (colour temperature) used to measure the whiteness of the light output. The higher the number is the whiter the light is.
Watts: the power intake of a light - this is a VERY subjective way of stating a lights power or brightness since, depending on the efficiency of the bulb, a 10 watt HID could produce more light than a 30 watt Halogen, and probably more than a 90 watt incandescent.
|
But due to the fact that it companies can advertise their lights at watts, lumens, lux, or candlepower, it makes it really difficult to actually compare illumination with just numbers on paper...
Some sneakier companies may also use these ratings to give the customer a false impression of the performance of their light. For instance, some companies use Lux (or "candlepower") ratings to make their light sound better than it is. Just remember when reading light ratings, that a small keychain laser pointer is MILLION "candlepower" or more, but try riding at night with one of those!
Hence why the best way is to compare is to actually see the lights in action themselves in a dark area with enough space to give a realistic impression of what they would be like on the trail. Also bare in mind, that colour temperature (the colour of the light) makes a big difference as well on the trails. The whiter the colour of the light, the closer it'll resemble daylight, and therefore create the best visibility and definition for seeing objects and your environment - a handy thing when you're hurtling down that technical downhill trail at night…. |
 |
|
