Trike Lights

This is a how-to for a set of lights for a recumbent trike. The system consists of 3 headlights and 3 taillights, all running off a central power block. It is capable of being run off a variety of batteries (as long as there are at least 7.2 volts) as well as bike generators (12 volt 6 watt type). I decided to build this system because it is much more powerful than typical bike lights and much cheaper than the high-end systems.

Check out the web site:
http://steubenswheelmen.blogspot.com/

Step 1: Parts List

Here is the grand list of parts!

-Clear bullet lights
-Red bullet lights
-Large red bullet light with fins
-Large white bullet-style bike light
-Red LEDs - Digikey part 67-2061-ND
-White LEDs
-White LED Resistors
-Red LED Resistors - Digikey part TWW3J8R2-ND
-Two battery holders - Digikey part BH24AAW-ND
-Waterproof project box - Digikey part HM954-ND
-Power switch - Digikey part CKN1019-ND
-Five volt regulator - Digikey part 296-8157-5-ND
-Bridge rectifier - Digikey part VS-KBPC108-ND
-Circuit board - Digikey part 3405K-ND
-Soldering equipment
-Wire
-Epoxy; caulk or hot glue would probably work fine as well

Note: Not all parts are pictured.

Comments

[unaffiliatedperson]

i made these. however im not sure if i need a driver. i got two 3.7 volt batteries in parallel they allegedly put out 2400 mah but my leds put max output at 1000 MAH and im using the reflector as a heat sink

[abadfart]

this one has nothing to do with your lights but i was looking at your trikes and was wondering what you did for your front axles

[wobbler]

In Step 5, what is the purpose of the bridge rectifier? If you are bothered about damaging the circuit by accidentally putting a battery in wrongly, I would simply put in a single rectifier. If you're not bothered about putting the battery in the wrong way because you can't (I have a similar system on my bike but I leave the battery permanently connected and charge from a wall charger via a resistor and polarised DC connector. I have a blocking diode on that to stop both reverse current and the charger being accidentally the wrong way round. The disadvantage of putting the bridge rectifier in the primary light circuit is that it is giving two diode drops across it and will be wasting approximately 2v of the battery voltage. Putting in a single diode will at least limit the drop to 1v and also save you some money. However, if you are driving it off a dynamo it is obviously necessary, although then I would also put in a capacitor after it to smooth out any flicker.

[spyfoxy]

The plan is to have a dynamo as a power option, even though it is not currently in use. Ideally, I'd like the ability to switch between batteries and dynamo. Caps would be nice for a dynamo powered system, but the flicker isn't really that bad, barely noticable.

[wobbler]

Thanks for replying. On my bike, I use 2D cells on my current system. You can get them at up to about 10Ah which means they last a long time. The light I use for seeing by is a modified 3W torch which used 2D cells via a DC-DC chip. It is 3W Cree LED based and very very bright if a little narrow. I also use a standard 3v flashing white bike light to be seen by at all angles and a rear red flashing 5 led light. Total consumption including back light is less than 1.5A so it will give a long time of use. I originally had a bottle dynamo system but I prefer this as the drag from a bottle dynamo was not fun plus I can switch out the 3W Cree for when I am on lit roads and only need to be seen! However, I had a bike a long time ago with a hub dynamo and that was superb, very little drag if at all in real terms, it would be brilliant at keeping this charged and probably allow smaller batteries to be use..

[lemonie]

What is your connection with the site http://steubenswheelmen.blogspot.com/
?

L

[spyfoxy]

I post there on occasion! Although I'm not the primary author there heh.

[lemonie]

If you're admitting that these are not photos of your work and you've just copied them because they look good - you should take them out and replace them with photographs of something you did do. It's not right if these ain't your trike!

L

[spyfoxy]

Nono. My boyfriend (the photographer) and I built it together, it's our trike. The site is our blog.

[lemonie]

(you should say so in the introduction) L

[Yerboogieman]

Nice pictures!

[spyfoxy]

Thanks! Although I'm not the photographer so I can't claim credit there. :) The photographer is the other author at the Steuben's Wheelmen blog.

[jolshefsky]

Rather than using power-robbing resistors, I have been using the more-expensive (but more efficient) constant-current DC-DC converters such as the buck- and boost- "puck" line from LED Supply. Because they are constant current, you can wire your LED's in series and use only one converter per string. The "buck" converters step the voltage down, so if you take all the LED's in series and add up their forward voltages, you need about 1 volt more than that for an input voltage. The "boost" converter increases the supply voltage, and you'd need a supply with less than your forward-voltage sum minus 3 volts.

You can also run identical LED's in parallel (i.e. use a buck converter with 3 red LED's in parallel) but the current is distributed to each LED equally (as long as they have the same forward voltage drop). Thus, 3 LED's with a 1000mA converter will drive each LED at about 333mA.

[spyfoxy]

Thanks for the comment! I do know about the efficient DC-DC converters, but the problem is that I determined that each LED would need it's own converter. I can't connect the LEDs in series because I want to retain the ability to add/remove LEDs while on the trail (via little plugs I can unplug). If they're in series, I'd lose the whole set of lights!

I could do parallel, but it is actually not a very good idea to connect LEDs in parallel unless you are sure they came from the same batch. Technically you can do it, but it can shorten their life if they have minute differences in their voltage drops. Constant current power sources are out for parallel LEDs because I want the ability to add/remove LEDs on the trail. If the circuit is built for 3 LEDs and I remove one, the current would be all wrong. But yea, "officially" (officially being defined as according to my analog devices professor), connecting LEDs in parallel=bad unless you are sure they came from the same batch/substrate. Even identical LEDs from the same supplier are different from batch to batch.

So yea, I do love the idea of using DC-DC converters, but really I'd like one for each LED so I can configure which lights are on/off. (For example, on the trail I just use one of the 3 tail lights because there are no cars on the trail and having all 3 is bright enough to annoy other trail users.)