H4 Bulbs

From: David Harrison <harrisonfamily@worldnet.att.net>
Date: Sat, 26 Sep 1998 12:23:28
Subject: H4 Lamps

I am forwarding this discussion of the Raybrig H4 to the general list after being encouraged to do so by Brian Curry. I have gone out of my bootlegged testing business since my original Xenon-filled halogen test sequence.

IMHO and 30-something years of experience there are a simple set of trades in incandescent lamps. You can spend more money for exotic fills, which is the state of current production lamps, requires just dollars, or francs, or rands or whatever you find convenient. After that there are simple trade spaces: input power, operating temperature, and lifetime. You can have any two of those three.

Operating temperature will affect lifetime. A constant input power at a higher temperature will yield higher light output, but at the expense of operating lifetime. Anyone who claims lower input power, higher temperature and longer lifetime simultaneously is likely not telling the truth. There is a possibility that a manufacturer has found a better fill to improve the art, but the current literature does not indicate such a breakthrough. More input electrical power will buy more light output without compromising lifetime IF the socket for the bulb is designed to handle the power. Interestingly, I have seen no comments on changing the bulb mounting when going to higher power. That could also be a source of abbreviated lifetimes, hotter bulb base with greater stress on the glass to metal seals.

As far as another writer asked, a 9003 is an H4 with DOT certification for automotive use in these United States. The Sylvania/Osrams have both 9003 and H4 stamped on their bases. I just looked at my 9003 cage spare and it is clearly marked H4. If you cannot find an H4, go to the automotive section and buy a 9003, usually a little more expensive.


Dave H - not a lighting engineer, just an engineer who has applied lamps in designs (terrestrial and space) for over 30 years. Cut my teeth on the first halogens when they turned deep purple during cool-down.

> From: Brian Curry <bmwbrian@voicenet.com>
> To: David Harrison <harrisonfamily@worldnet.att.net>
> Subject: To the black body radiation guy. Re: BMW: H-4 Headlight Bulbs
> Date: Tuesday, September 22, 1998 10:52 PM
> >The Raybrig H4 "Super Beam Halogen Bulb" comes in blue, white and yellow.
> >The draw is 60/55w, yielding 130/125 output.
> >The color of the hyper whites is 3,800 degrees kelvin.
> >Warrantee is one year.

No it does not make sense, especially with a 1 year warrantee, potentially 9000 hours. The strawman comparisons to 130/125 mean nothing without specifying the bulb type. For all we know they could be comparing it to a non-halogen bulb optimized for long life. The color temperature listed is pretty high. If it is the filament temperature, the bulb life is probably very short. If it is color temperature, then the blue goop will bias the normal 3200 Kelvin halogen up to the reported 3800 Kelvin and reduce output lumens, the stuff we detect as visible light. Color temperature specification by itself means very little. It is also amazing that they can maintain a 3800 Kelvin color (their words) with a yellow filter.

My opinion is that there were quite a few snakes squeezed of their oils in the marketing of this product.

As far as lifetime, it is interesting that people with higher power lamps are reporting longevity in miles instead of hours. One person's 3000 miles might be the same operating lifetime as another's 6000 miles. My total average speed is probably around 30 mph, considering that I spend a lot of time on back roads and in the city. My brief forays over the ton generally do not use up much of the hour rating of my bulbs. I estimate that the mileage reports are likely equivalent to 100 to 200 hours of operation, about right for a bulb run hot for higher output.

I have yet to burn out a motorcycle bulb, a bit fussy about changing $8 bulbs before I have to. My cage uses the same 60/55 standard H-4s and I usually get 500 to 1000 hours on a low beam, never burned out a high.

Enough of my pontificating, thanks for the query.

Dave Harrison

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