Headlight - Halogen to LED

[MMACH 5]

I currently run two headlights on my 45-mile commute. One is a NiteRider Trail Rat Select, 15w halogen with a 4.0 Ah-6 Volt NiMH battery. The other is a Planet Bike Super Spot, 1w LED with rechargeable AAs.

I used to only use the LED, but there are areas along my commute where it does not give me enough light, especially if the pavement is wet. So I got the halogen which gives me plenty of light, but its runtime is too short for my ride to work, let alone the ride home. Travel time is 1.5 to 2.5 hours, each way and the Trail Rat claims to have a run time of over two hours, but I've found that it is done at just under an hour and a half. I think this is because the manual that came with it is for a Trail Rat II which comes with a 10w bulb.

So now I use the LED for most of my commute, it gives me enough light to ride on the street, as long as there are street lights. The halogen only gets kicked on when I'm in areas without street lights. Usually for about five minutes in the morning and 15 minutes in the evening, (the sun comes up part way through my ride to work).

NiteRider does not make a dimmer switch or LED for this light. I think either one would allow me to drop the other light altogether. I'm hoping to extend the run time by either running the halogen at half or quarter power, (save for the aforementioned twenty minutes) or replacing the halogen with a 3w LED.

If either option doesn't allow me to make a full round trip, I can always keep another charger at my desk to charge it while I work.

Would a 3w LED give me as much light as the 15w halogen?
How much more efficient is a 3w LED than a 15w halogen?
I'm guessing I'll go with a modified u-bin.

Thanks.

 

[Szemhazai]

Depends on halogen class :
HQ 15W halogen will give you 300+ lumens / Cree XR-E R2 @ 800mA wil give you 200+ lumens.
More than 3x more efficient, at higher currents (over 350mA) and more than 4x at lower currents (to 350mA).

 

[MMACH 5]

attached to the back of the LED?Sorry for my ignorance, but is the current determined by the "circuit board" Is that the driver?

Is there such a thing as a variable driver, (with a dimmer switch)?

I could see how being able to run at half power for most of my commute, even with the LED, could be helpful in extending run time.

Thanks.

 

[Szemhazai]

In the bikelights - not, in the flashlights it's quite common in case of little space avalible for batteries.

Yes, the driver is setting the current (sometimes the resistor is enough) - advanced drivers can offer 4-5 dimming levels so you have multiple choice . Look for Luxdrive BuckPuck + pot & TaskLED drivers.

 

[n4zou]

You could install a tire driven dynamo to recharge or supplement the batteries for your halogen light system. The dynamo will easily supply 6 volts at 500mA for your batteries. If the lights are off you will be recharging them with 500mA of current. With the lights on the batteries will have 500mA helping to power the lights so run time is extended. As an example if your lights are drawing 1.5 amps adding the dynamo would supplement power for the lights so the battery drain would be 1 amp instead of 1.5 amps. If your battery is rated at 3 amp hours you would extend run time 1 hour for 3 hours of run time instead of the normal 2 hours of run time. Turning off the halogen lights with the dynamo engaged recharging the batteries would extend run time even more when you need to turn on the halogen lights. You'll need a simple diode bridge rectifier to convert AC produced by the dynamo to DC for the batteries. Here is the circuit I use on my touring bike.

I use a standard bottle type dynamo rated at 6 volts-3 watts.
S2 prevents power drain from the batteries when the bike is parked.
The 4 Ni-MH batteries regulate voltage to 5.2 volts (USB standard voltage available on USB connectors) and provide a place for excess current produced by the dynamo. They also provide power for any electronic devices connected to the USB connector. I power/recharge a GPS or Cell phone with the USB connector as I pedal along.
S1 disconnects the LED headlight and taillight during the day and when powering and/or recharging USB devices. You can't power USB devices and run the lights at the same time.
The resistors are used to limit the current to the LED's. Current draw is limited to 380mA. This provides 120mA of excess current produced by the dynamo to recharge the batteries to compensate for stops and hill climbing. This provides a lighting system that never goes out when the bike is stopped or moving very slowly and I need never worry about the batteries ever going dead.

 

[BUZ]

You need this! :naughty: :naughty: :naughty: http://www.cpfmarketplace.com/mp/showthread.php?p=2124624#post2124624




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