Tom Barber

I few weeks ago I ordered some new 100 Watt H7 bulbs from classicgarage.com. The little plastic container that they came in says "Mega White". They have a slight blue coloring on the glass. "Made in Korea" is printed on the metal base.

I wanted to be able to compare these with the stock bulb, so naturally I only installed it on one side, the driver's side. When I pulled the car up close enough to the garage door so that the pattern thrown by each side was easily distinguishable, I could tell that the new bulb threw a broader pattern, both in width and in height. But I wasn't sure whether this was useful, and I wasn't sure that in the same area that was light by the stock bulb, that the new bulb was any brighter. When on the highway, there is no way to determine what light originates from which bulb because they overlap substantially starting only at a few dozen feet.

I kept trying to figure out how to tell whether the new bulb was brighter. I don't have a garage door opener so when I open the gargare door I also walk into the garage and open the door to the inside. When I did this this evening I was paying attention to the light pattern on the far wall and as I approached the wall I noticed my two shadows converging and then overlapping in the middle. The overlap area is the umbra. I dropped my arms down to my side in order to make a reasonably smooth outline, and on both sides of the umbra there was a half-shadow, where light from only one or the other of the two headlights reached the wall. As I faced the wall, the left penumbra was shaded from the passenger side light, but was lit by the driver side light. The right penumbra was shaded from the driver side light, but was lit by the passenger the side light. The penumbra on the left was noticably brighter than the one on the right, and was also noticeably whiter, i.e., less yellow.

The 100 Watt, blue-tinted bulbs were clearly brighter, but not nearly as much as they should be. The blue tinting is just barely visible on the glass, so there is no way that it absorbs enough light to explain the difference. I checked the resistance of both bulbs, and although my little Radio Snack DVM isn't very precise at this low resistance, it was accurate enough for me to determine that the resistance of the "100 Watt" bulb is only about 20% lower than that of the stock. Of course, the resistance will change when the filaments get hot, but I assume that they will change by a similar proportion. Power is inversely proportional to resistance for a given voltage, so these bulbs are actually only about 20% more powerful than the stock bulbs, which agrees perfectly with my subjective observation.

These bulbs cost $13.50 each, and shipping was another $8.44. This is a rip-off. Do not buy these bulbs.

Does anyone know of a 100 Watt H7 bulb that they are fairly certain is a true 100 Watt bulb?

Jim De Arras

trying to "eyeball" light differences is nearly impossible. A better test would be to illuminate a uniform subject and use a light meter. A camera or camcorder that displays settings would be close. Again, I do not know the brightness to f-stop ratios, but I'm sure that is a known science and can be derived.

My test was to observe the top line of the lo-beams, with the highs on. That line was much less noticable with the 100w highs, so they are brighter. 55w to 100w worth? Maybe, maybe not, but certianly closer to 100 than 55.<p>Jim De Arras

<a href="http://www.imola.org">2000 00 Imola/Onyx/Alcantera S4</a>
MTM Stage II on order (III on hold :-( )
MTM Suspension on order

nubS4

I believe the blue is not a "tint" but the true color of the quartz after processing.

Tom Barber

I have done similar replacements in motorcycles in the past and the difference was like night and day. Watts are Watts, whether the voltage is 12VDC or 120VAC. The difference in a 55W and a 100W house light bulb is enormous. The difference between the stock bulb and this bulb is just barely detectable. It is probably about 65 Watt.