Not if you build a 12v system are willing to use a simple but uncool sealed lead acid battery. 5ah battery is only about $11 at just about any electronics or battery store and will drive a 20W light for over 2 hrs. You can put it in a handlebar bag or in a box on a rack trunk. I used a Carlon 6x6x4 junction box with a 12v lighter plug and push button switch mounted on the box. I can actually take the box off and use it as a light duty 12v power supply for anything with a lighter type plug. The box was waterproof, but I drilled rows of tiny upward angled holes just under the lip of the cover for ventilation since most batteries say "Do not charge in a sealed container." As a precaution against splashing and to make the box blend with my panniers I cover it with a piece of waterproof black cordura just held in place by the staps that hold the box in place, leaving one corner loose enough to acces the lighter plug for charging. Every few months I open the box just to check on things and have never seen the slightest sign of water intrusion.

If sla is too unstylish you just may not be geeky enough to hang with this crowd. :D
FWIW,
Raymond

Adding to that...if you want something lighter, you can use a 12V hand-drill battery. My 18V' drill battery weights about 1.5lbs--has alot of umph but it's limited in what I can hook up to it.

The only thing that would worry me about that setup is the "standard" charger. Judging from personal experience, it wouldn't be long before I'd plug it in on a Friday and forget all about it until Monday morning, at which time the NiMH cells would likely be fried. Of course one can use one of those plug-in timers, but I just know I'd forget, or I'd be in a hurry, or whatever, and sooner or later it would be toast. The $35 charger might seem like a lot to pay but it sure is nice to not have to worry about it if you forget to unplug it. Plus you can use it to charge any 6 to 12v NiMH (or NiCD's I believe) you might have over 1100mAh.

Regarding the battery weights, I pondered the cost/weight thing on SLA vs. NiMH for a long time before I decided the extra cost was worth it for me. But truthfully I'm still not totally convinced. If I'd have gone with SLA I might have added about 3 pounds, which certainly isn't much. Now if I were commuting 50 miles a day and was very concerned about speed and weight, it might be a different story. But I just plod along at about 14 to 17mph on a mountain bike with knobby tires, so, I dunno, SLA probably wouldn't have been a bad way to go at all.

I am thankful that I don't feel the battery though. I'm no spring chicken anymore and need all the help I can get.

Hey awesome....LittleBigMan....your thread is now a permanent "sticky"

Soft-start circuit: I've whipped up a soft-start circuit for my 12V halogens, after experiencing (and witnessing) some power-on blowouts. Whether it will actually help bulb life is anyone's guess. I've posted it over in my Hello, and my "Total Geekiness" entry thread.

Keepin' the night away,

JAB

Glo gloves, bought a pair of them www.gloglov.com. I commute about 20 miles a day all weather. I am quite happy iwth what I got, they are comfortable and highly reflective.

Glo Gloves are great. I posted a thread about them some time ago.

With all due respect, I will remind posters again that this thread is about homemade light systems.

I don't know, Ray, Glo Gloves sound pretty geeky...

:D

Oh, no! The Geekiness has spread!

My roomie just geeked up his bike with an absurdly powerful LED taillight, accompanied by a flasher circuit with a brake switch sensor. Attached are some pictures.

620nm at ~3.5W: it's what's for dinner!

Covering my eyes,

JAB

Hey, that's like the one I have, but I just have it hard wired on high intensity. Nice mount. Is that a piece of black pvc drain pipe? How is the light itself held in the mount? Grommet? Adhesive? Is there a back on the pipe or is it open?

jab,
I would like to build the flasher circuit you designed. I have built a few kits long ago, so I think I could probably manage the soldering. I was wondering where you got your components? Thanks for any assistance you can give!

Any body have thoughts on the significance of the height of the tail light? i.e., what is the optimal height of the tail light?

You've got it: it's the flared-out end of a 4" ABS fitting, cut just past the flared portion. The light itself is too wide to fit out the narrow (tail) end of the ABS segment, and my roomie used zip-ties through holes in the sides to "seat-belt" it quite securely in place.

The back (facing front) of the assembly is currently open; I think he's going to attach a cover of some sort.

JAB

I'd like to help!

I've been buying my electronic components at Fry's; they carry the "NTE" line of products. (You can find datasheets at http://www.nteinc.com/.) In the flasher, there are just a few resistors/capacitor/diodes, a 555 (or equivalent) timing chip, and a high-power PNP transistor. It's a simple enough design that it shouldn't take much to adapt it to the parts you happen to find at, say, radio shack; just make sure the transistor can handle lots of current, and adjust R3/R4 so that it turns on and off cleanly.

Unfortunately(?), I'm a couple of hours away from a period of extended travel, where I doubt I'll have Internet access. :( I'll try to check back in when I can, but it'll likely be a few weeks before I'll be able to.

All the best,

JAB

I needed a flasher for the back of my bike so I dropped by the dollar store and bought a handfull of of little red marker lights for a dollar each. I have been riding to work 1 hr each way for about 4 mths now and still havent changed the first 2, came with the battery in it. It flashes 3 ways, slow flash, 3 flashies than stop, and a constant flicker. FOR A BUCK. For a head light I have a flash light with a magnet on it so I just stick it to the cross bar and away we go! Batteries are free work takes care of that we use rechargables for our cattle prods so when I need a fresh set I just switch.

My rack has a mounting bracket on the back; that's where mine is, along with the turn signals. Kinda like a motorcycle would have.

I figure drivers are looking for taillights at car taillight height, so that's where mine is (which corresponds nicely with the seatpost). On the other hand, the past 10 year's move to having stop lights in the rear windows of cars (bottom for sedans and often top for SUVs and vans) suggests that higher is better.

I don't know that there's been a scientific study on the subject.

Check RonH's tail light from the Commute Pictures thread.


The taillight setup.
http://home.mindspring.com/~rhorne/Jamis%20002.jpg

vrkelley asked for some details on my taillight setup.
I made a T bracket from an aluminum strip (~4" tall and 4" across the T) and bent it in the right places so it would attach to the underside of the rack. The lights are two Vistalite Super Nebula 5 mounted to the bracket. I set all the lights (except the headlights) on the bike to flash mode.
If you go to my post in the commuter pictures thread you can see the lights and reflective tape in the daylight and how visible the bike is at night.

RohH

Awesome! So is the Amber strip above the Vista's a llight then?
What sorf to head light setup is that?

Question for the electrical whiz-kids. I liked the idea of using a truck LED taillight, so I got one of those and some stick-on amber LED bars (meant to go at the top of a truck cab) on my front fork and I wanted to add a strobe on the trunk for good lateral visibility. At every stage of the build, the strobe worked fine. I've taken it out 2 nights now and I'm very happy with the taillight, front fork lights and horn; but the strobe light now goes on once every 90-120 secs, in otherwords it's useless. Any idea where I screwed up? Not being very good at soldering may be a factor. To simplify wiring I don't have any switches, I just put a 2 socket auto accessory adapter into the Vector 12V battery (it puts another fuse in) and plug in to turn everything on. The wires to the strobe are a lot finer say 20 vs the 16 on the rest of the system. Any suggestions on how to start figuring whats wrong?

First, if the strobe has an adjustment for speed of flash, check that.

Second, check that the battery is charged. When they're low, strobes slow down.

Third, re-check all your connections. If the solder joints aren't shiny-silvery and smooth looking, get your soldering gun and some flux out and re-make the joint. That may even include cutting the wires off, restripping them, and doing the connection all over again. (Besides, that's good practice at soldering! ;))

Also check your wiring to see if you may have wired the strobe in series instead of parallel.

Any computer types out there?

I have just replaced the UPS batteries on our servers at work. Each battery tray contains 4 9Ah deep cycle sealed lead acid batteries! Since we replace them annually, they are still in good shape.

I have not been able to find 20W halogens around here. So, I purchased a set of 55W driving lights. I am currently testing the run time using the 9Ah battery and a single light from the set. If this works as I hope, I'll have an awesome base to build my lighting system.

My commute is mostly rural and really need some serious light. Sure hope these work out! I'll post results of the test. Perhaps even some photos as things progress.

Bob

interesting. I have 3 APC 1400's in my office sitting unused. I think the batteries are dead but if I remember correctly they're less than $20 on ebay. And that's for 2 batteries!

They should have a lot of power, I remember once powering 3 computer and 6 monitors for about 25mins off of an APC 1400. I don't know how that compares to a 55W halogen bulb, but 6 monitors suck a lot of power.