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Headlight overheating danger?

Allen Rowand

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I put the Aerostich headlight protector on a while back- the one that has adhesive that goes directly on the lens. Today I installed an Eastern Beaver headlight relay kit (still using a stock bulb) and am wondering if the higher output will cause the lamp to overheat with the film on the lens.


What a difference in output! I know it's not HID, but my headlight looks like a proper light instead of a little candle behind a lens. Thanks for the idea, Selden!



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I wouldn't worry about it. Due to the extra heat the bulb may fail a bit sooner but for the extra visibility you achieve it sounds like it would be a reasonable trade-off.

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At the other end, I replaced my brake light bulb with a Candlepower 55 watt halogen. Big mistake: both the socket and the part of the tail light assembly it plugs into are melted. If I can buy a socket alone, I think I can futz with the tail light assembly enough to get it to fit and stay in place.


Anybody have a surplus R1100/1150RT tail light assembly they want to unload cheap?

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I don't think the incremental increase in output using the same headlight bulb with relays will cause any problems. It's only a few tenths of a volt you gain, it would be on the order of a 10% increase in power at worst. If you were switching from a 55W to a 100W bulb, then you start to be concerned. But with the headlight relay, you're upping the power from 55W to maybe 60W - not enough extra heat to worry about.


Bulb output is non-linear, that's why you get a huge increase in light output from a small increase in voltage. Quoting from Daniel Stern's lighting site :


The drop in light output is not linear, it is exponential with the power 3.4. For example, let's consider a 9006 low beam bulb rated 1000 lumens at 12.8 Volts and plug in different voltages:


10.5V : 510 lumens

11.0V : 597 lumens

11.5V : 695 lumens

12.0V : 803 lumens

12.5V : 923 lumens

12.8V : 1000 lumens ←Rated output voltage

13.0V : 1054 lumens

13.5V : 1198 lumens

14.0V : 1356 lumens ←Rated life voltage

14.5V : 1528 lumens

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SO, now you have me curious. I am going to put a volt meter between batt + and the + on the bulb to see how much voltage I am losing. I'll do the same for ground. I doubt its more than a couple of tenths.

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