My new lights

[Borriz]

I felt like Poena in Poena is Koning when I saw your lights "JEEEEEEESSSSSSS"

[madmarc]

This a beam shot of a mate who has one in the UK. Exactly the same as mine. He has 6 narrow optics! hows this for a beaut beam!!

what is the distance to the car +- ?

 

Approx. 70mm if you measure from the bottom of the photo

[BenDL]

 

[

No, 21 volts

Remember, there are 6 leds with a Vf of 3.5 v each. they are arranged in series so it's 3.5 x 6 = 21V. the Driver boosts the voltage requirement to that which the lights require. So even though you run a 14.4 v battery, your leds are drawing 21Volts.

Power in watts is the current x voltage

P = 500ma x 21

P = 10.5W

 

hope this helps.

T

Yes, that clarifies it.

Driving voltage is 21V

It draws 500mA, as a constant current source.

 

So on a 5Ah battery pack you will get theoretically 10 hours, but the

battery pack will shut down before that so realistically -

5 hours?

 

[Capricorn]

how do you overcome the fact that with a series arrangement, if one LED blows, or gets popped by a rock or something arb, the whole lamp goes belly up?

[Slowbee]

also can you post a pic of the lights on low setting .... will it last for 12 hrs ?

 

 

 

[leet22]

U planning on cycling for 12hours Slowbee

[thysmeades]

 

Hi Gents, a group response

Madmarc : the car is about 70 m from the light

Builder: I will post actual runtimes when I finally do the test.

You can drive the LED's at 700mA (max recommended) but I under drive them for a longer runtime. I have heard of guys running them at 1000mA with no problem, other than heat!! and shorter runtimes.

Capricorn: you are right, in series, if one blows for whatever reason, the whole light will stop working. LEDs typical life span is 35000hrs so you are pretty safe there. I would rather have them in series than parallel, because if one blows in parallel, the remaining 5 will have to handle the same current, (ie the current increases per led) which could blow another, then 4 will have to handle the same current and another could blow and  ...... can you see where this is going

Slowbee: the driver has 5 level settings, on low it will last 20 - 30 hours plus. as I said earler, actual runtimes and beam shots will be posted in due course.

Borriz: Thanks

Supertorro: Please do post your lights, it's for the enjoyment of the hobby that we do this and sharing it with our mates. The only way I learned was to see other guys posts. So lets see what you are hiding there!!

 

Just to whet your guys appetite for more, below are beamshots of my best light yet. It's a triple Cree MCE called the Supernova Altair MCE. It will blow most things out the water. I will put the pics in a new post, for some reason I cannot past the pics here.

 

 

 

 

 

 

 

thysmeades2009-07-31 00:35:43

[thysmeades]

 

Supernova Altair MCE - Enjoy..

 

 

images removed

Sorry guys

 

 

 

 

 

 

thysmeades2009-07-31 08:57:29

[AndreZA]

That Altair is nice. I actually like it more then the 6 LED one.

 

 

 

Can't you make a super small one for helmets. Maybe just one LED and a small 3hr battery that can attach to the helmet.

[rad006]

I want price, I want Price

[samson99]

Agree with Mampara, need a helmet light. If you design one, pls let me know.

[Capricorn]

 

 

Hi Gents' date=' a group response

Capricorn: you are right, in series, if one blows for whatever reason, the whole light will stop working. LEDs typical life span is 35000hrs so you are pretty safe there. I would rather have them in series than parallel, because if one blows in parallel, the remaining 5 will have to handle the same current, (ie the current increases per led) which could blow another, then 4 will have to handle the same current and another could blow and? ...... can you see where this is going

 

[/quote']

actually, that is incorrect. The total current is a function of the total resistance drop per light element plus what ever resistance is added. With say 3 elements, each element takes only a 3rd of the total current flowing in the circuit. Keep causing elements to fail causes the total current draw to drop by amount of which each element normally takes. I just did a simple calculation of a 3 element parallel resistance circuit,and failing each element in turn results in exactly what which I explained.

If what you said was true, we would have had street lights blowing all over the place each time ?a whole neighbourhood gets blacked out. But that is obviously not the case.

From a fault tolerant perspective, a parallel circuit arrangement is the best. I would hate to have something where if one goes, it causes the whole system to face plant. that's not a good design.

in fact, if one light element fails because of poor manufacturing, and with your current series arrangement, the whole unit faceplants, how do you know which element to replace? you would have remove everything and test each one individually.

Ever see those rear bar style brake lights made using LEDs? ever wonder why some of them have gaps where light elements have failed but the whole unit still works maintaining its function? The benefits of parallel circuits.

Capricorn2009-07-31 01:07:53

[mountain_lion]

Nice work, thysmeades!

Are you now the SA agent for troutie-mtb of mtbr forum fame?

 

http://forums.mtbr.com/showthread.php?t=487467

 

http://forums.mtbr.com/showthread.php?t=493687

 

[thysmeades]

ok, cool. well explained. I will however still build in series as it is best suited to my drivers. If however after 35000hrs it stops working, I think you got your moneys worth.

[thysmeades]

 

Mountain lion, YES! Troutie is the king of light building.

 

You however are the reason I actually built my first light so THANKS!!! I read your light build post.. and the rest was history..

 

I spoke to Trout about his design and if he was happy that I base my design on his. He said it's cool   I think mine is smaller than his.

 

I actually mention and thank him at the beginning of this post. the one you see (pocket rocket) was made locally here in PE and it came out quite nice. I have a guy currently working on locally CNC'ing them here for me. Once I have price, production starts.

 

thysmeades2009-07-31 01:18:54

[MooZN]

 

 

 

 

Hi Gents' date=' a group responseCapricorn: you are right, in series, if one blows for whatever reason, the whole light will stop working. LEDs typical life span is 35000hrs so you are pretty safe there. I would rather have them in series than parallel, because if one blows in parallel, the remaining 5 will have to handle the same current, (ie the current increases per led) which could blow another, then 4 will have to handle the same current and another could blow and? ...... can you see where this is going

 

 

[/quote']

 

actually, that is incorrect. The total current is a function of the total resistance drop per light element plus what ever resistance is added. With say 3 elements, each element takes only a 3rd of the total current flowing in the circuit. Keep causing elements to fail causes the total current draw to drop by amount of which each element normally takes. I just did a simple calculation of a 3 element parallel resistance circuit,and failing each element in turn results in exactly what which I explained.

If what you said was true, we would have had street lights blowing all over the place each time ?a whole neighbourhood gets blacked out. But that is obviously not the case.

From a fault tolerant perspective, a parallel circuit arrangement is the best. I would hate to have something where if one goes, it causes the whole system to face plant. that's not a good design.

in fact, if one light element fails because of poor manufacturing, and with your current series arrangement, the whole unit faceplants, how do you know which element to replace? you would have remove everything and test each one individually.

Ever see those rear bar style brake lights made using LEDs? ever wonder why some of them have gaps where light elements have failed but the whole unit still works maintaining its function? The benefits of parallel circuits.

 

 

 

 

Actually I think Thys was correct, bear in mind that LED drivers are constant current drivers, so in a parallel arrangement, if one LED blows and stops drawing current, the driver will detect the current drop and then increase the drive voltage to the LED's to bring the current back to the original value, causing the remaining LED's to share the extra current not being drawn by the blown LED.

 

 

 

In your street light example you are correct, but in this case, the lights are being driven by a constant 220V supply that will not change no matter how many lights are connected.

 

 

 

In the rear flashing light is also effectively a constant voltage arrangement, where each LED has it's own current limiting resistor and is driven directly from the battery voltage.