"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. 

Step 1: What you'll need:

Tools you need are:
Multimeter (even the cheap Harbor Freight DMM is fine)
Soldering iron and solder
wire cutters
wire strippers
needlenose pliers
Dremel or other cutting tools are handy
Drill, bits, etc.

Optionally you may need whatever tools your bike requires for adjustments, disassembly, etc, if you have to take anything apart or adjust it to make room for these lights, and/or to install them on the bike.

If you have an electrric bike, you'll need to make a splice into the output from the battery pack, preferably *after* the fuse or breaker that feeds your motor controller.   I recommend using the same kind of connectors already on your pack, and making a Y-splitter that can simply be plugged in between the pack, controller, and this new lighting setup.  If you bought yours as a kit, get the connectors from the same place if possible--this will ensure they are the right ones, if you dont' know a lot about this.  If they offer a Y-cable already, get that.

If your battery pack is less than the voltage required to start the CFL (call it 48V) then you will also need a way to boost that a bit.  Interestingly enough, laptop wall adapters/chargers and celphone wall chargers often work on 36V ok.  The only wa

If all you have is 24V, you may not be able to do this without making a battery pack specifically to put in series with your "traction pack" (the main motor power battery, as most of the adapters I've tried won't start on 24V or less, and aren't stable at their regulated voltages at that low an input.

If you don't have an electric bike, you'll need to get or make a battery pack that is fairly high voltage.  I don't cover it here in the instructable, but if you do it, be careful, as there are potentially dangerous amounts of power available in a battery pack with 40+ volts in it, even if you make it out of AA batteries, depending on what goes wrong (because something always does eventually, for somebody).

You'll need at least two CFLs, of the 110-240V 50/60Hz variety, preferably in a "60 Watt equivalent" size.  You can use larger or smaller, to fit your desired brightness, but that's what I used.  Mine are GreenLight brand, bought at the Phoenix, AZ "99 cent" stores.  At the time they were being sponsored by APS (local power company) at only 59 cents each!    I got them originally for the house to save money on electricity (it makes a significant difference).  

If you can, find some cheap ugly lamps you won't mind taking apart at a yard sale or thrift store, and try not to spend more than a dollar on each one.   All you are going to save out of them is the bulb socket.    It is best if they don't have a switch *in* the socket, but rather a separate one on the cord, or a chain pull for those hanging lamps.   If the cord is in good shape, all the better, because you can reuse the wire from it, too.  If it's frayed or cracked or old-looking, recycle the wire with the rest of the lamp.    You can buy sockets from the hardware store, too, but where's the challenge in that?

You'll need something to put the lights in on your bike.  For the headlight on mine, I used two cups that nest neatly inside each other--a styrofoam white one (because it reflects a lot of light and lets less thru than a thin white plastic cup would) from Denny's and a tough thick plastic outer one from QT.  Those were picked more because they were laying around than any other reasons besides those stated.     For the taillight, I used a taillight assembly off a dead Honda scooter from the 80's, mostly because the CFL would light it very well and thoroughly, and it is already a tough, water-resistant DOT-approved shell.   (I'm sure the approval is nulled by not using the lamp and reflector that came in it). 

For the taillight, you could use any kind of item or box that will help aim the light behind you, covered in red cellophane or party wrap, if you had no other way. :)

For the headlight, you could also use one of those clamp-on lamps with the large aluminum parabolic reflectors, often used for reptile and small animal habitats for heat lamps.   Depends on how much "throw" you expect from it to see by at a distance, rather than just using it to be seen by and for close-up vision.

A way to secure these to the bike is necessary.  I am still working on a good headlight mount (and a better housing), so the headlight is just taped in place with wraps of packing tape for now.  The taillight is securely bolted to the rear plate I already had an LED taillight on before, which had been transplanted from my original DayGlo Avenger bike to this CrazyBike2 early this year.

A roll of duct tape is fine if you don't care how it looks. ;)

<p>CFL's contain mercury, so be careful if you break one...</p>
Very nicely documented, five stars, and Happy Thanksgiving!

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