Niterider 19-LED taillight.
 

I dropped by the local sports shop and they had an open box niterider digital evolution 12 tail light (their largest cluster with 19 LED's) for sale for $19.95. All the connectors were missing but I figured I could deal with that.
So I bought it, got an 8-AA battery holder from radioshack for $2. Spliced the wire from the niterider and hooked it up to 8 nimh 2500 milliamp AA's. I'm measuring around 10.2 volts from it. Supposedly it's even brighter at 12 volts but it's damn bright as is. Put the battery pack in my saddle bag and I'm ready to go. Draws around 350ma so I figure with self drain and all and only on the night commute, I'm good for a week before having to recharge.
Here's a pic of it with the (clockwise) niterider tail light, a cateye 2-LED blinker, the planetbike helmet mounted blinker, and a specialized blinker. All the white spots are reflective tape.

Wow looks link my niterider tails... now you can see why I only use niterider lighting on my bikes.

(A little heavy though)

I run mine on 12AAs (14.4v). I like it.

Haha how many chargers do you have? That must take a while to charge every time. I measure my nimh's at around 13.1v fresh, that's gotta be like 15.7v, must be one helluva bright light.
I like the 8AA setup cause the 8AA case is one unit with 4 on each side and it makes battery changes easy since my charger takes 3 hours to charge 2500mah I can do both banks in 1 night.
The ratshack has these cool 15 minute rechargeables but they're too expensive.

I fastened an 8 and a 4 together to get the 12 and wired an RC type connector to it. The charger I have has an RC plug as well so I can charge all 12 at once. Here is a picture that just shows the headlight, the taillight stays on the bike. This is my setup using two sets of 12 in parallel. I built it so I can use it either 1x12 or 2x12, but I don’t need all those amp hours so I usually just use 1x12.

“The ratshack has these cool 15 minute rechargeables but they're too expensive”

I bought some of their AAAs just to try them out in my Cateye Opticube I run on my road bike. Their mah rating is higher than most AAAs. I haven’t done any kind of tests on them, but they seem to perform ok.

Very clever !!! I think their tailight is their best product.

Holy, what is that, a pipe bomb?

Great, now Home Land Security will be all over this thread! Do peopple use PVC for those ?

No doubt. This weekend, I replaced the mounting bracket in the picture with the one from my 6v Digital pro. I went through 3 of them in 3 years via warranty and finally gave up, but the taiight keeps on blinking.

I don't know but if they come a'knockin, you don't know me. :p

I just hooked up the light to the power supply here at work to check the current draw.
Below 5.75 volts, only 3 LED's seem to be on. At 6, it's pretty dim. It gets bright enough to call it bright at 7.2v.
So: volts/current
7.20/.017
8.40/.044
9.60/.073
10.8/.103
12.0/.133
13.2/.161
14.4/.190

Seems completely linear with current=0.0242*voltage-.1583

Assuming that I use it 1 hr a day and it depreciates .1amp/day, I figure I can use it for about 1.5 weeks of commuting before having to recharge again but I've only been using it a day.

How's your mileage?

Hard to say. I am running a 1 amp LED through a 12v automotive emergency flasher on my headlight. I can definitely go all week.

I have the Niterider tail light and headlamp, 12 volt. I assumed that the tail light when hooked up to an external battery does not flash. Is this so?

Yeah, it's just solid. I'd prefer it to be solid since people get more of a perspective of where I am. If needed, I have a helmet mounted blinker that flashes.

"I assumed that the tail light when hooked up to an external battery does not flash. Is this so?"

Mine blinks if you hit/hold the button just like it did on the nightrider battery

Mine doesn't flash. :(

for the price it is not bad. but it is not any briger then otehr setups for less then the full cost. dragging 8 batteries around for the tailight is just too much really. the new cateye taillight is very bright and far lighter. you want even brighter a xenon flasher will do it. both are cheaper and it is better not to have everything running on one battery set.

Is this new magical Cateye light available in the US yet? What is it's model number?

Can you recommend a make/model for a xenon?

it is only somewhat availibe so far as it is pretty new. but since it lights on the sides too it is pretty handy. I have used the liteman xenon flasher it has great vilisiblity from the sides but you only get 4 to 5 hours run time max from a set of batteries. then there is the sparky that lets you choose three colors but does nto have much side to side visibility you can get 15 hours out of it.

http://www.bikeforums.net/showthread.php?t=68186

You can try ebay. Or go to www.sheldonbrown.com, his harris cyclery http://sheldonbrown.com/harris/lighting/index.html has it for sale for $35.
Basically it looks like a large D-cell battery, kind of like a keg. It uses 2 AA's and it has two rows of 3 rear facing LED's and one on each side facing 90 degrees away.

Steve, I thought the cateye lasted something like 100 hours on blink and 20 on solid.