Today I’m going to be covering motorcycle light bulbs on your ride, how to see things better — and more important — how to be seen better. But in order to do that, I’m going to have to toss around a few electrical terms. You know, like watts and volts and amperage.
Wait! Don’t hit the Back button, because I’m going to try and make this as easy to comprehend as possible.
A watt is a unit of measure that takes into consideration the mathematical relationship of volts and amperage. What it looks like is this: Watts = Volts X Amps.
The standard motorcycle headlight that comes attached to most of today’s models has a rating of 55/60. That means the low beam draws 55 watts (12 V X 4.5 A), while the high beam draws 60 watts (12 V X 5 A). The higher the wattage, the more light is supplied.
How we doing so far? Still with me? Good. Now a great number of halogen headlamps are using a two-piece system that has a reflector with a changeable bulb. These changeable bulbs are given numbers like H3, H4, H7 and H13. There are higher wattage bulbs available in this type that can provide even more illumination.
For instance, we offer German Rally bulbs in 55/60, 80/100 and 100/130 wattages. But I digress. Going back to our formula, a 100W low-beam bulb draws 8.3 amps (12V X 8.3 A = 100W) while a 130W high-beam bulb draws a whopping 10.8 amps (12V X 10.8 A = 130W).
These bulbs add new meaning to the term bright! However, this is acceptable up to a point. Higher wattages require heavier components to handle the higher current load. These higher wattages increase the amount of heat produced and require a metallic or glass reflector. Some lower-priced halogen reflectors are made of plastic, and these high-output bulbs can easily melt the unit. In addition, the wiring on your bike is only designed to handle a specific amount of power.
Changing to one of these Rally bulbs will most likely require an increase in the size of the wire going to the lamp in order to keep it from melting or burning up. Sounds like a lot of effort in order to get a brighter lamp.
But this brings us to a neat solution engineered by the PIAA Corporation. What PIAA has done, is increase the light output, without increasing the wattage required. These bulbs are a bit more expensive, but modifications to your bike are not required. And that’s a good trade off, if you’re asking my opinion.
We’ve got one bulb here at J&P — Part No. 330-752 — that doubles the light output with the standard 55/60 wattage requirement. And if it makes any difference, this bulb is on both of my family’s motorcycles.
Another thing to consider with these super bright bulbs is the effect they have on the bike’s charging system. Shovel’s 1966 to ’84 come with 15-,17- and 22-amp alternators, and early Evo BTs 1984 to ’88s have 22-amp alternators. Sportsters 1967 to ’79s have 10-amp charging; the 1980 to 1984s have 13 amps; the 1984 to ’90s have19 amps; and bikes between 1991 and 2005 have 22-amp systems.
Upgrading to the higher-wattage bulb is impossible on the smaller-amp charging systems. To upgrade, the 22-amp system would be the lowest amp output recommended. There just isn’t enough current output to run everything required, and keep your motorcycle battery charged. Big Twins built from 1989 on have a healthy 32-amp alternator, so this isn’t a challenge.
Now, what’s your opinion of LED lighting? This acronym stands for Light Emitting Diode, and these little guys provide a lot of light with minimal wattage requirements. Used as a tail light/brake light on our bikes, no changes are required. However, when used as a turn signal, we’ve got issues.
In applications that have a self-canceling turn signal, a load equalizer is required. Since the LED light changes the wattage in the circuit, the difference in current draw will confuse the original processor into thinking that the bulb is burned out.
This can cause a no-flash or double-flash condition and believe me, we get a ton of calls about this. A load equalizer, like those from Badlands, will correct this condition by fooling the processor into thinking the stock bulb is still in the circuit. Your new LED turn signal will flash and cancel normally. A load equalizer is also required if a small, marker light is used as a four-way flasher.
Due to possible heat buildup in the unit over a longer period of time, it’s a good idea to keep usage down to a minimum. And just a reminder: While these small, marker lights look good on a show bike, they should not be used on the street, because they can’t be seen as easily as a DOT-approved light, especially in the daytime.
I certainly hope this sheds some light on today’s subject, and hope I set things out in an understandable manner. If not, our friendly and savvy tech staff is always available to answer any questions that you may have.