Difference between H9 and H11 bulbs?

rushnrockt

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I've tried searching forums and the interwebs, but have not found a good explanation yet. There is a minor difference in the connector, which many easily get around and H9 is a 65W bulb instead of 55W for H11. That doesn't seem to explain the ~750 lumen difference between the two. Anyone wants to shed some light on this for me? Thank you.

EDIT: Mods, please move to automotive forum, I had too many tabs open! *embarrassed*
 
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mrb

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I believe the H9/65w makes more lumens by being run harder, it has a lower filament resistance and also half the life of H11/55w.

The bulbs are not really interchangeable, one of the metal tabs and the socket needs minor "adjustment/modification".
Some H11 lamps may not be up to the job of running a H9 without problems.

Also on Daniel Stern's product page it looks like that particular H9 does not have the same treatment to the envelope probably meaning they are only suited to lights that have the inbuilt bulb shields.

I'm sure next time Scheinwerfermann is online you will get the definitive answer to their differences.
 

tay

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Harder driven filament, no glare cap, higher wattage, shorter life. But significantly higher output.

FMVSS says 70w maximum, 1760-2240lm for H9
versus 59w maximum, 1100-1400lm for H11

I know the electrical connector is slightly different (but easily modified). I have H11 and H9 here on my workbench and the twisting socket tabs are similar but not identical, however my H11 projectors were able to fit H9 bulbs without a problem.

With a decent headlamp, H9s are a major upgrade. However, I wouldn't reccomend it for H11 foglights or for lamps that don't have a glare cap built in but need one.

I posted this about a month ago. The second set of pics is a comparison between H11 and H9.

https://www.candlepowerforums.com/posts/3171747&postcount=34

The beam pattern is completely unaffected, but it does get brighter (which is most noticable to the sides... the center is overexposed on the pics, but its the quickest exposure I could get on my point-and-shoot)
 
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rushnrockt

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Thanks for the responses, I figured that some trade-offs have got to be part of the equation. Tried looking for lifespan comparison, but getting stuck in many forums discussing the actual alteration from H11 to H9, not the technical merits of the bulbs.
 

-Virgil-

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It's basically a matter of different filament with different characteristics. The H9 has a 65w (nominal) filament optimized for maximum luminance and flux at the expense of shorter lifespan. The H11 has a 55w (nominal) filament optimized for long life at the expense of lower luminance and flux. Both bulbs have equal filament precision, etc.
 
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