Help needed with bike light project...

[Hairyeyeball]

Hi,

I posted in the LED forum but was told to try here instead as you guys will have a better idea on what I should use as what I thought would be ok obviously isnt lol

I have some lights I wanted to convert to LED as they are originally car and motorbike lights

The rear light I have is one of these http://cgi.ebay.com/ebaymotors/PAIR...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

The front light I have is one of these http://cgi.ebay.co.uk/Chrome-Bullet...66:2|39:1|72:1689|240:1318|301:0|293:1|294:50

They are going to more for looks than function as the bike wont be used at night very often.

For the rear light I was giong to use these:
6 x 8mm Superbright red leds -
Lens type: water clear
Viewing angle: 40°
Forward current max.: 30mA
Forward voltage max.: 2.5V
Reverse voltage max.: 5V
Wavelength @ peak : 660nm
Power dissipation PT: 100mW
Light output min.@ 20mA: 3000mcd
Light output typ.@ 20mA:3800mcd

Would that be ok? I was hoping to use it as a brake light too.....
Maybe running at half power and then full power when brake is applied or have 3 running and then all 6 running when the brake is applied.... Would be nice but not important.....

As for the front!!! I have no idea what LEDs to use....

I would like to have a high and low beam if possible but again, thats not overly impotant.....

whats your thoughts on this?

Any help would be great and thanks in advance

Trevor

 

[Steve K]

hi Trevor,

My first questions would be regarding the intended use of the light, and what the power source will be. I bike commute and use a hub dynamo, so my recommendations tend to fall into this pattern.

For the taillight, your choice of leds should be pretty good. I tend to use leds with a narrower beam, but that's a matter of choice. Since you don't have a power source picked out, you can add leds in series to get the right voltage, and then run parallel strings to increase brightness to the desired level.

Brake lights are not all that useful, in my opinion, but there's no reason you can't make one. The hard part is to sense when the brake is activated. You might try a microswitch to sense the position of the brake lever or the brake caliper. A reed switch and magnet is another option. Just make sure you use a switch rated for the current that you'll be using.

Converting headlight to leds should be possible. There are some triple optics that should do a good job. I tend to use the Cree XR-E white leds for my headlights, as they work well and there is a good selection of optics available for them. The hardest part might be heatsinking the leds to the headlight body. leds need to be kept cool, or they will die an early death.

These are just a few quick ideas to think about. I'm sure that you'll have more questions as you begin the project.

cheers,
Steve K.

 

[pe2er]

I Would totally recommend my own setup

For the rear LED, use a red 1W Luxeon or similar emitter. I Would not bother with these small LEDs you mention.

Click here or on the picture for below a description of my system:


For your headlight conversion, I would consider using a CREE Q5 LED drop-in module instead of the fully assembled flashlight I used.

 

[Hairyeyeball]

Hi, Thanks for your input...

The lights are mostly for show so being really bright isnt to much of a priority although I would like them to be bright enough for other people to see me coming...

as for the battery... well... I dont know yet lol I have one of these floating around somewhere that I thought about using to get me started but would like something a bit more suited to the job. Do you have any recomendations? It will have to be a similar size and shape to the one I linked to(or smaller) as I plan to have it hidden in a compartment I will be fitting under my seat which is very similar to a mk2 raleigh chopper seat.

The brake light switch wont be a problem as I have plenty of little switches ets that I can use depending on where I decide to place it.

The front lights housing is made of high impact resistance ABS plastic which I doubt would be anywhere near adequete for usng cree leds as I read that they need heat sinks etc as they can get quite hot so I was thinking about avoiding these and going for standard leds instead, like this kind of thing. But instead of the leds being on a flat plate I was thinking of fitting them directly into the side part of the reflector (which is also made of plastic) instead of the base where the standard bulb currently sits.

Trev

 

[Steve K]

The front lights housing is made of high impact resistance ABS plastic which I doubt would be anywhere near adequete for usng cree leds as I read that they need heat sinks etc as they can get quite hot so I was thinking about avoiding these and going for standard leds instead, like this kind of thing. But instead of the leds being on a flat plate I was thinking of fitting them directly into the side part of the reflector (which is also made of plastic) instead of the base where the standard bulb currently sits.

Trev

The 5mm leds that are used in that ebay light do still get warm, especially when you cluster 56 of them into a small space. The leds just don't have any way to get rid of the heat, so you don't realize how warm they are. They just die after a couple thousand (hundred?) hours instead of 100,000 hours for a properly cooled led.

You might consider wandering around the hardware store and seeing what copper or aluminum pieces they sell. You might be able to polish up a piece of aluminum hardware and make a good looking light. Or check the scrapyard for an old steel headlight housing?

That light on ebay is pretty cheap, so it's worth giving it a try. If it dies quickly, then you'll feel justified in finding a better housing for a light.

cheers,
Steve K.

 

[Hairyeyeball]

thats not to bad because they wont be used for long periods of time or that often anyway.
I think I will start looking for a similar light with a metal shell so that I can use the cree leds in it. but in the mean time I want to carry on using the one I have seeing as though its my first time making anything like this and want to have some kind of idea what im doing before tackling a better light lol...

Do you have any suggestions on what type of battery I should use instead of the one I have as its a tad on the heavy side because of it being lead-acid lol and not very appropriate for the job lol

Cheers
Trev

 

[pe2er]

Most batteries used on modern 'CPF' bike lights are of the 18650 LiIon type. I Use 18650 'protected cells' that do not get damaged by discharging them below the recommended minimum.

There is a thread on this forum about http://www.candlepowerforums.com/vb/showthread.php?t=232232]using LiPo for Bike Lights. You may want to consider using them also. Using undervoltage protection during use and care during charging become even more important with LiPo.

If you only occasionally use the lights for show, you may even consider using primary (Alkaline) cells for convenience

 

[Steve K]

Do you have any suggestions on what type of battery I should use instead of the one I have as its a tad on the heavy side because of it being lead-acid lol and not very appropriate for the job lol

Cheers
Trev

I already have a bunch of AA NiMH batteries and a charger, so my choice would be to buy a simple battery holder, put them in some sort of pouch or bag on the bike, and run wires to the lights. Might want to buy a voltage converter/regulator to drive the lights, or perhaps just use enough AA cells to get the voltage that is used by the light.

Deal Extreme seems to be a popular source of a lot of the voltage converters, but there are also places like LED Supply that sell a lot of the parts needed for this sort of project.

Steve K.

 

[Hairyeyeball]

AHHhhhhhhhhhhhhh! good thinking batman!!! I have around 20 rechargeable AA's floating around..... will have a look around for a battery box that will fit in the seat! How many should be enough? 8 @ 12v??

That should save me a few ££££s lol

Had a look at that thread and dont like the look of them when they blow up eeek!!! lol

 

[Neondiod]

Hello!

As this is your first led lamp project I suggest that you keep it simple.

The red leds for the rear light seams good, the have a deep red emitting color, 660nm, which should look good. I think a powerled is overkill in this particular project, even cars and trucks use small leds as break lights.

For the front light a, grap a few cheap 5mm leds and move them `lit`around inside the fronlamp and see what resault it gets. Aiming then sideways in the reflector is intresting. Maybe you can take out the reflector and use the hosing as a refector with the leds at the rear?

BR

 

[Hairyeyeball]

I found these
http://www.virtualvillage.co.uk/2-red-led-1157-car-bulbs-with-36-leds-each/sku007525-003
and these
http://cgi.ebay.co.uk/2X-68-LED-Whi...66:2|39:1|72:1683|240:1318|301:0|293:1|294:50

Think they have the same fittings as the lights have now.... will have to double check though!

Would still have to sort out something for a brake light though and would I be able to add a potentionmeter or switch to the front one to dim it for the high/low beam?

 

[Steve K]

AHHhhhhhhhhhhhhh! good thinking batman!!! I have around 20 rechargeable AA's floating around..... will have a look around for a battery box that will fit in the seat! How many should be enough? 8 @ 12v??

NiMH or nicad cells are generally 1.2v when in use. They will go down to 1.0v when fully discharged. 10 cells will give you 12v (assuming that's the desired voltage).
For battery holders, I've always like the metal ones from Keystone:
http://www.keyelco.com/products/prod39.asp?SubCategoryID=14

Not sure if they are available in the UK, but there must be something similar that is available.

Steve K.

 

[pe2er]

... I have around 20 rechargeable AA's floating around.....

I Would think twice about using random AA cells in a 10-cell battery pack. It would not damage your light, but using cells of different capacity/ age could create problems with the battery cells. Typically, the cell with the lowest capacity will be damaged due to undervoltage/reverse voltage condition.

 

[Hairyeyeball]

Oh I see.... 12v would be the voltage I think id need to go for as I found some led bulbs that should fit the lights I have, would just need to add a couple of leds to the rear light for my brake light which should be easy for me to do now. only thing I will have trouble with now is the dimming of the front light... would a potentionmeter do that or a switch?
just been trying the batteries and half of them are buggered so will buy some new ones...
Can you get battery holders for the 18650 batteries? will have to make my own if not....

Oh and would just like to say thank you for all your input and help guys.... its grately appriciated

 

[pe2er]

For the battery holder, look at this thread: 4 x 18650 Battery Adaptor

 

[Hairyeyeball]

Thats a good thread... Would never have thought about making one that way. Could do with something like that myself but would need to be a flat 4 holder (side by side) to fit into the compartment im putting into my seat.
It will only be about an inch deep at the most so wouldnt be able to fit the 4x holder he's made into it. maybe 2 of the 2x holders would work though....

 

[pe2er]

That sounds a lot like my own battery pack:


I Used new 18650 cells and soldered them together to get a flat pack like you described. I later found out, that it is possible to damage the LiIon cells when soldering them. Just was lucky I guess that nothing blew up

Other people on this forum reclaim 18650 cells from old laptop bateries (look in the Elecronics - Batteries Incuded section of this forum). These have solder lips so you can easily assemble a pack.