$5 Radio Shack rechargeable spotlight.
 

Currently, radio shack has a 1 million candlepower rechargeable spotlight for $5 until 12/24/06.
Here it is online. As you can see it's not the ideal bike light, but paired with a front rack, it might do a good job, or at least be a fun little project.
I think I'll try it with a cheap used blackburn pannier rack from the LBC (local bike co-op).

Hm.m. tie that on the back rack and put a red lens or red clear wrapper over it then just ride. I'm sure cars will stay hella away from you.

1mill cp = how many watts again?



Zero_Enigma

This says that they can't be converted.
BUT, if you take the "watt to light output ratio" of HID lights as a constant, wiht some data it can be done.

You know, for the money and considering it is rechargeable with a 50 to 60 minute run-time, that isn't such a crazy idea. That is a LOT of light at a very affordable price, especially with the rechargeable feature. With the exception of the low run-time and the fact that it doesn't have mounting hardware, it is a reasonable consideration.

Imagine riding with one or even TWO of those on your bicycle. Automobile drivers would think that a snow plow was coming at them.

Open up this light and you will find a 4 Amp Hour 6-volt SLA battery and 6-volt 50-watt halogen bulb. Be very careful you don’t touch the bulbs glass envelope. If you do use alcohol to clean it, as it will quickly burn out. Drop by a big box retailer's automotive supply department and purchase a pair of small halogen driving lights. That 6-volt bulb from the spotlight will fit perfectly. The driving lights typically cost $14.95 and $19.95 for a pair. The very small driving lights will be easy to mount on your handlebar using an EMT conduit hanger from the electrical supply area of any building supply store. They also wont look odd at all on your bike. As for recharging the battery, just find an old wall wart transformer that powered some now defunct gizmo with a rating of 6-volts DC and something around 500 mA. Make sure you connect the positive lead of the transformer to the positive lead of the battery! It will normally take over 8 hours to recharge the battery and you can leave it connected all the time as 500 mA is considered a trickle charge and it's impossible to over charge the battery.

The runtime may be less if it is cold. If the run time is good enough for you, go for it. Don't forget to consider how long it takes to recharge overnight if you want to use it every day.

Thanks n4zou for the contents of the spotlight. A 4amp/hour battery 6 volt battery means 24 watts for one hour. A 50 watt bulb should drain that in under 30 minutes. Likely dim in under 20 minutes. I will check the local store today. If they want over $5.00 I will have the web site ship it to them. Next would be to see if a 12 volt replacement bulb would melt the plastic. If not I will switch and use my 12 V system.

Thanks for the detailed information.
I will be sure to mess around with it once I buy it.
One thing that can be added it a sort of dimmer switch, so that I can dim it a little if it's too bright, and prolong the battery life.

2manybikes = next sheldon brown when it comes to bike lights?

Also could I rig up a way to charge it though USB? which is 5v and 500mA.

try a DC to DC converter that takes the 5 volts at 600+ mA and jumps it to 7.2-7.5 volts with corresponding drop in current. If you must use USB. Safer to get a basic charger that uses 120V AC from a wall outlet. And likely cheaper.

Wow, one million candle power! Should be just enough to blind oncomming drivers, disorienting them as they swerve into your path and run you over.

It was out of stock when I got there, sold out yesterday morning, at the beginning of the sale....
I bet they only had 2 or 3 of them.
EDIT: and now they took it off their site, I call bait and switch.

It's a lot of power for the money for sure, don't be too impressed by the power, I have a bike light that is the same amount of light, and one that is quite a bit more light, that I use all the time. My bike light is much more noticeable to a motorist because of the wide beam pattern created by the lens. More like a flood light. That $5 spotlight will not appear too blinding to a driver because the lens focuses the light into a tiny spot.
The problem with that thing is that it is a spotlight. It's a little less power than a car headlight, but it is a narrow beam to focus the light on something farther away than a car headlight. So you can pick out a mooring float, or a house number at a long distance. It's not a good lens type for bike riding.

By all means give it a try, at that price you could just throw it away, or use four of them. You can ride with it all you want, it will work, I'm just saying it's a very narrow beam and not amazingly powerful. And a short run time for some riders. But for $5 it does not matter. Put three on your bike ! :D

I have 3 lights kind of like this back from my pizza delivery days (great for shining on houses to see the address) and:

1) Way too freaking heavy and bulky. Depending on the size of the 6 volt SLA battery, it could weigh 5-10 pounds total and most of those are about 6" across on the light lens.

2) As was mentioned before, too narrow a beam. Great for SEEING down the road with, but wouldn't make you seen all that easily. There's light scatter that is really wide, but it's also very, very weak compared to the focused beam.

Cut-rate retailers like Big Lots and Fred's put these things on sale like this all the time. It's cheaper to purchase one and strip it for the SLA battery than purchasing a new SLA battery alone. Those PR-3 Halogen lights are a bit overkill. If your good at DIY you can easily homebrew your own lamp holder that will fit in a PR-3 bulb mount. The trick is making sure when you have constructed your mount to make sure the filament in the replacement bulb is exactly the same distance from the mounting washer on a real PR-3 bulb. This ensures the focus length is correct. I simply use JB Weld to epoxy a metal socket to a washer that will fit in the PR-3 socket in the reflector and run the wires from the socket through the washer. This way you can use a lower wattage, easily available bulb in those cheap automotive lights.

I went to the local RS this morning and there were two left. I got both of them. The manager said they had sold a lot of them. The wife wants me to mount both of them on my handlebars. Sure it gives a little spot when it is close to you so aim it out at 100 yards and it will fill the whole road. Just do not aim it up into drivers eyes. I like the idea of putting red film over one on the rear. Then put it in a wobble mount so the beam covers the road (and side roads) behind you.

After reading this thread, and since I had to make a trip to Radio Shack for some phone equipment, I purchased a 5 dollar spotlight. I do not plan to mount it to my bike since I do not wish to make the motorists anymore irate than they already are. :D The spotlight will be very handy to have whenever our power goes out or for use when we go camping.

Similar spotlights are also available from Harbor Freight, frequently in the $7-$9 range. I purchased some over the years & tried them as a bike light on my short 4 mile commute. Produced similar light to a car headlight but run time was in the 15-25 minute range depending on the particular light(battery). Quickly decided it wasn't suitable without modifying, as to heavy & difficult to mount but perfect for taking my dogs out into the woods or down by the lake.(putting a reflector on the dog makes them easy to spot) Most lights only lasted 10-12 weeks of daily use before the battery died, but a couple good ones went for over a year! Well worth the price. Don