Upgrading halogen light

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I have a cateye 6v 10w halogen headlight with a dip and full beam function. Quite the thing about 7 years ago, but surpassed now. Last year I bought a new battery for it. This year I'm wondering about replacing the bulb with something brighter - a 12w for instance.

Is this possible? Do the bulbs come in one size? Or are they different sizes? And what effect will it have on run time?

Any help appreciated.



Senior Member
I don't think you can get 12W models. You might also have issues with heat if the lamp body is plastic - I melted my cateyes like this.

The best performance lights for the money in the entire universe are as follows:

Philips 20 watt ES MR16 bulb 8 degree - about £4)
14.4V NiMH (best from the USA if you have contacts) - about £30
cheap METAL MR16 housing - About £8

For 20% more voltage you get 160% of the brightness! So for less than £50, you can have something that easily out shines any HID or LED on the market almost regardless of cost. You will pay in runtime though. I use a 35W set-up with a bigger battery and it was still less than £100. It is comparable to a car dipped headlight.
Behind a desk
Yes, it's curious. I was comparing the old Cateye rechargeable halogen with the new Opticube on the road last night. The halogen has been completely surpassed - the Opticube is lighter, brighter, lasts longer and was cheaper. LEDs have become a mould-breaking technology.

What is the runtime on the model you describe above? And how do you wire it up?


Senior Member
Believe me, your LED would not outshine this halogen. It's gives you about 800-900lumens from a 20W lamp.

Wiring up is easy, just a length of mains flex. A switch and a fuse might be a good idea.

The tiny halogens aren't ever going to be very effiecent, because you cannot use a decent relector. Going for this bulb and running it overvolted will give you around 3 times the efficiency.

As a guide:

cycle lamp (MR11) 11 lumens/Watt
Typical incandescent light bulb 15 lumens/watt
Typical domestic halogen 18lumens/Watt
ES type halogen (upto) 25lumens/watt
old-school luxeon about 45 lumens/watt
bike HID lamp (alwyn welch) 50lumens/watt
latest cree LEDs up to 85 lumens/watt
flourescent strip lighting 90-100lumens/watt
high powered HID lighting (stadiums, security etc) upto 120lumens/watt
Maximum possible (all energy into light) 683.002lumens/watt

An overvolted halogen ES lamp when overvolted can give you upto 34lumens/watt so you can see how typical bike LEDs and HID lamps (40-50lumens/Watt) are not really "all that", especially when you consider the price difference and that fact you need no fancy electronics.

The latest LEDS are (literally) brilliant. The problem being you can't get much more than 3Watts out of each emitter (some do 5 but efficiency sufffers). This means you'd need 4 and possibly 5 of the latest and greatest to even come need a simple domestic halogen and a bit of know-how.
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