H11 to H9 Headlight Bulb Conversion

Discussion in 'Gen 3 Prius Accessories and Modifications' started by zebelkhan, Sep 23, 2012.

  1. zebelkhan

    zebelkhan Member in good standing

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    Has anyone replaced the existing H11 bulbs in their Halogen headlights with H9 bulbs? H9 lights are much brighter than H11 and are a good replacement candidates because they maintain their luminous characteristics when installed in a halogen based lighting system.

    I was originally planning to instal an HID kit in my Prius thinking because I had a projection headlight (for low beam) there would be no glare and therefore it would be legal. However I have found out that is not the case. A halogen lighting system, even if projection type, is not designed for HID so with a HID bulb it will have a completely different physical and luminous characteristics leading to all sorts of issues.

    This article by Stern helped answer a lot of my questions.

    Daniel Stern Lighting Consultancy and Supply

    So, to gain the higher light output, my alternative would be to change headlight bulbs from H11 to H9. I am thinking since I am staying with a halogen bulb, it will be compatible with the optics of the existing headlight.

    Here is a quick comparison:

    H11: 1,350 Lumens, @ 55 watts, runs cooler and has longer life
    H9: 2,100 Lumens, @ 65 watts, runs hotter, has shorter life

    One minor problem is that the plugs are a bit different. H9 has an extra tab but that can be easily fixed by cutting the tab off.

    As noted above, H9 has a 65-watt (nominal) filament optimized for maximum luminance and flux at the expense of shorter lifespan while H11 has a 55-watt (nominal) filament optimized for long life at the expense of lower luminance and flux. Both bulbs have equal filament precision, etc. So all else being equal, while providing more light, H9 uses a bit more power (10 watts) so inevitably it will run a bit hotter, but I am thinking that should be insignificant and inconsequential to the headlight components.

    Here is my main problem: Unlike most other vehicles, wiring in Prius is very thin, mostly 18 and higher gauge wires. I am not sure if the higher power draw, even if it is only 10 watts per bulb, will cause some damage to the wiring. Short of installing the lights and hoping for the best, does anyone have any suggestions, recommendations, or experience with this?

    Thanks in advance.
     

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  2. bino

    bino JDM ZVW30

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  3. gliderman

    gliderman Active Member

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    Anybody have a picture of the bulb tab and connector conversion? Thanks!
     
  4. zebelkhan

    zebelkhan Member in good standing

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  5. zebelkhan

    zebelkhan Member in good standing

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    Thanks. I had not seen that thread. But the main question I have is still unanswered. Will the additional 10 watts of power damage the thin wires in the Prius?
     
  6. xliderider

    xliderider Senior Member

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    Your fuse will likely blow before you melt any wiring. Whether or not there are any effects long term, on your light housings, etc. remains unanswered.
     
  7. terpsmandan

    terpsmandan Member

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    I do not have my manual close by but at 55w you will draw 4.5 amps at 12 volts. So 65w will draw 5.4 amps. If the low beam fuse is 15a you should be fine. Check your owners manual.
     
  8. xliderider

    xliderider Senior Member

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    Geez, for $54 I'd sell them too if there wasn't the elephant in the room called liability. :rolleyes:

    Buy the bulbs for under $20 and modify to fit, I'm talking about German made Osram or Philips. You don't even know if you're getting good quality bulbs or not with that Amazon kit. Could be $2 Chinese bulbs, now that's a profit lol.

    SCH-I535
     
  9. mediahound

    mediahound Active Member

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    That makes sense although it would be nice to have the adapter wires at least. Especially given that the H9 bulbs are only supposed to last a couple hundred hours. Who wants to be cutting bulbs that often?
     
  10. xliderider

    xliderider Senior Member

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    Do the math.

    For me, I drive 30 minutes one way 5 times per week, on average, with my headlights on. Times 48 weeks per year. That's only 120 hrs. 500 hrs average life for the H9 bulbs gives me over 3 years. ;)

    Honestly, I'd be happy to get 1 year out of them because they're so inexpensive compared to the "premium" H11 bulbs that go for at least twice the price.

    SCH-I535
     
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  11. mediahound

    mediahound Active Member

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    I wish there was someone who would measure the temperature of an h11 bulb to see how it compares to that of an h9 bulb in the same headlight projector. Would also be nice to know if the wiring gets at all warmer running an H9
     
  12. xliderider

    xliderider Senior Member

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    Do a Google search for the H9 conversion. Someone did take temperatures of the H9 vs the H11. Can't remember which forum it was on, maybe a Subaru WRX forum.

    It was basically a non issue.

    SCH-I535
     
  13. xliderider

    xliderider Senior Member

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  14. mediahound

    mediahound Active Member

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  15. mediahound

    mediahound Active Member

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    Why is there such a discrepancy in pricing of h9 bulbs?

    Looking on Amazon for example: http://amzn.to/1lTH56s

    Philips ones go for as little as $15. a pair and others are as high as almost $70. a pair!

    Are the more expensive ones any better? I know they are trying to be 'whiter'.

    I'm happy with the Philips ones I'm using now and the brightness is an improvement over the stock H11 bulbs, I would like a slightly whiter light if possible.
     
  16. xliderider

    xliderider Senior Member

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    I've tried several H9 bulbs now, including some blue ones that give "whiter" light.

    The visible light on the road, so you can make out detail and potholes, is much better with the clear Osram bulbs than with the blue bulbs.

    If you want the blue ones for aesthetics, go for it, but the warmer temp bulbs give you more effective light on the road.

    SCH-I535
     
  17. mediahound

    mediahound Active Member

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    Good to know, thanks. I guess it's not worth it to buy the expensive bulbs.
     
  18. mediahound

    mediahound Active Member

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    So I was doing the mod last night on an extra set of H9 bulbs and thought I would video it.

    This could come in handy for those searching, etc:



    Thanks to xliderider for the Black & Decker suggestion. Great tool for the price.
     
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  19. xliderider

    xliderider Senior Member

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    Great video mediahound! (y)

    Very clear and easy to follow. Here is a shot of the bits I use. The spiral bit is good to use because it's blunt on the end, so you can remove material flush, all the way down to the bottom:

    [​IMG]

    If you hold the RTX with this grip, you will have better control of the tool for precision work. ;)

    [​IMG]

    The red rubber seal at the bottom of the bulb base can be removed and replaced easily so you don't have to worry about grinding any of it away while working on the tab mod.

    SCH-I535
     
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