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CFL Headlight and Taillight for (Electric) Bicycles

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Rider View with Dogs 9 feet from Headlight ISO1000 AUTOMODE DSC02023.JPG
Full Bike Side View with Dogs 9 feet from Headlight ISO1000  DSC02031.JPG
1DrivewayOverheadsOff Rear View ISO1000 DSC02070.JPG
2DrivewayOverheadsOn Rear View ISO1000 DSC02073.JPG
3DrivewayOverheadsOn Rear View CFLs OFF  ISO1000 DSC02074.JPG
4DrivewayOverheadsOff Front View ISO1000 .JPG
5DrivewayOverheadsOn Front View ISO1000 DSC02072.JPG
6DrivewayOverheadsOn Front View CFLs OFF ISO1000 DSC02076.JPG
12 feet Away Oncoming View with Dogs 9 feet from Headlight ISO1000  DSC02030.JPG
CFL HL Front First Version DSC02006.JPG
CFL HL side First Version DSC02007.JPG
Yard Rear View CFL light ISO1000 DSC02080.JPG
"Electric" is parenthetical because the CFLs (Compact Fluorescent Lamp) need a high enough DC voltage to start, and carrying a battery that big around on the bike isn't practical unless you already need it to run a motor. ;-)

Many CFLs will run on as little as 28VDC, once they startup, but may take 44VDC or more to get them started.    The key is to find CFLs that say 110-240VAC, 50/60Hz for their input.  If they just say 110VAC, 60Hz, they probably don't have the right electronics inside to work without modification (which is outside the scope of this instructable).  In areas that use 110-120VAC household voltage, you should be able to use the ones sold where you live at around 44 to 60VDC.   In areas that use 220-240VAC, it's probably going to take *at least* 70VDC to run the ones sold in your area.  The best part of them is that they will only use about 150-250mA, so total power consumption for the light they give is very low, especially for the price. 

As with any other glass item, you should be aware that if you ride your bike where you expect big bumps or potholes, it's possible for the shock to break the glass tube off the base if you don't have any shock absorption for it.  I don't cover making that, but it's possible to do.  It's probably better to just use some other more solid-state form of lighting, even if it's more expensive--you probably need the better beam/spot those would provide, too.

This instructable assumes a typical road-bike scenario, in which the main purpose of these lights is for *others* to see *you*, not necessarily for *you* to see *by*, so you don't get run over in traffic despite obeying all the rules and watching out, simply because someone didn't see you in the dark.  With these, if they say they couldn't see you, and you're riding where and how you should be, they probably ought to take off the sleeping mask before driving.  :-P

There is no specific parts list, as you'll be scrounging the items according to what's available to you, with the exception of the type of CFL noted above.  

There are some additional modifications you can make to the bulbs if you really need a little more voltage headroom, but I don't recommend them unless you're absolutely sure of what you're doing.  Those aren't in this instructable, but are documented on my e-bike project blog at http://electricle.blogspot.com/2009/11/diy-cfl-hl-wdc-dc-inverter.html  if you are really determined.


The photos taken on the carport are first with just the bike lights, then with the overheads on, which are four 4-foot 40W fluorescents, then with the bike lights off and overheads still on, so you can see some relative brightnesses.  My camera does not let me set the exposure time, even in it's "manual" mode, so you will want to note the difference in brightness of relative lights when comparing images.  In one of the yard pics with the dogs, it used a one second exposure time which resulted in a lot of blur but gives a very good idea of what this looks like in person. 

 
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Electrospark2 months ago

CFL's contain mercury, so be careful if you break one...

yokozuna5 years ago
Very nicely documented, five stars, and Happy Thanksgiving!