# 24x p7 off road light array (3x p7 12v driver)



## monkers (Jul 11, 2010)

hi all,

i plan to build a LED light bar similar to these 52" xmitter light bars http://www.visionxoffroad.com/led/xmitter/ simply because these cost $2000 and i believe i can build one for cheaper using 24 p7 LED chips.. 

i was planning to hook up 3 in each circuit in series driven by one driver each... how ever im battling to find a driver that will power 4v @ 2.8A, does anyone have any suggestions on what i could use or build my self. i have a pretty good understanding of LEDs and electronics, so im not completely noobish.

also if anyone could point out a good lens/reflector that would be great im looking for 10degree ones, haven't found any yet in my price range. 

cheers.
m


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## monkers (Jul 11, 2010)

i mean a driver that is stable in a voltage range of 10 - 16v and puts out roughly 11-12v


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## CKOD (Aug 14, 2010)

the taskled H6CC looks like it could be a start
http://www.taskled.com/h6cc.html
you would need to overvoltage protection on the input to keep any load dump surges in the car from causing problems. 

If you want to cheat some you could probably do 6 LEDs from one driver. Parallel 2 chains, of 3 LEDS in series, and set your output current to 5.6A.

See if you can find 'I' voltage bin P7's that will be 3.25-3.5V for the Vf making your max string voltage 10.5 V then as long as your supply voltage is 11.5 or better, the LEDs will stay in regulation. But that depends on the Vf of the chains being very close to share current equally. 


I would also consider the bridgelux chips, available on newark, 
http://www.newark.com/bridgelux/bxr...ightness-led-arrays/dp/60R6539?Ntt=BXRA-C0802


the CRI isnt the best, and its a cool white color, but its more efficient then the other models. The max for the C0802 is 1500 mA in the datasheet, ~1400 lumens from 1400 mA @ 13.7v put 3 in series and you have a 41.1 V string running at 1400 mA (57.54 watts), with a 12v input, thats 4.79A drawn, within the 5A input limit by the taskled hyperboost
http://www.taskled.com/hboost.html

I'd contact taskled to see if it would work in that situation just to be sure before I invested serious $$$ into it. 

The hyperboost is $40, and the LEDs are $12.80, so you would be at 4200 lumens for $78.40 vs 6 SSC P7s which would also give a similar amount of light(slightly higher), but be $25-30 each, with a $32 driver. $182+ 

The reason you dont see the bridgelux used by the flashlight fanatics, is it uses multiple dies, spread out over a broad area, so it isnt good at throwing vs single high power dies. But if you want to flood an area in close, then they will be fine. Just be sure to heatsink everything WELL, going to be a lot of heat with ~60W of LEDs


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## jspec (Aug 27, 2010)

I have also been thinking of this. I am a bit supprised there is nothing like the vision x on the market for 1/2 the price. Come on china why aren't you listening.


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## monkers (May 19, 2011)

sorry for the delay but iv the project is on going between more important things.. and may take awhile. i also want to be 100% sure before i start spending money.

thanks for the advice CKOD that seem to be getting alittle more expensive than i was hoping.. i found this 
http://cgi.ebay.com.au/ws/eBayISAPI...26444&ssPageName=STRK:MEWNX:IT#ht_4978wt_1002 
on ebay which is alot cheaper rated for fairly high power however it dosent appear that you can set the current and also has a 3v difference between Vin<Vout.

the reason i chose p7 leds is i actually found a supplier that was goin to sell me 50 or so of them for a good price with the lenses that i wanted.. going to have to do some digging to find those emails now.

heat-sinking/fabrication is not a problem i have a friend in the metal fabrication business that has agreed to give me a hand.. plus i was considering connecting a thermometer circuit up to the on/off switch on this circuit to save the LEDs if something did go wrong.

what are thoughts guys?


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## monkers (May 19, 2011)

okay after doing some reading it looks like the h6cc is the best for the job i guess 4 of these for each light isnt to bad.. its defiantly in the right direction to compete with the xmitter prices


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## Simhinz (May 19, 2011)

jspec said:


> I have also been thinking of this. I am a bit supprised there is nothing like the vision x on the market for 1/2 the price. Come on china why aren't you listening.



Yes they would kill in the Off-Road sector, know allot of guys that just cant justify pulling the trigger on the VisionX stuff even though its really good.


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## Lynx_Arc (May 19, 2011)

I'm wondering if you have considered the Cree XM-L Leds out now instead of the P7s as the prices seem slightly cheaper and the cree may have better throw I would think.


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## monkers (May 24, 2011)

Lynx_Arc said:


> I'm wondering if you have considered the Cree XM-L Leds out now instead of the P7s as the prices seem slightly cheaper and the cree may have better throw I would think.


 
i hadnt even looked at them, and your right. looks like id get way more performance per driver for less $. so i think they will be the ones i cant seem to find any lenses around 10degrees though http://www.ledil.com/node/2/ they all say comming soon..

so im currently designing the housing and heat sink on cad so i can use universities cnc router transfer to blue foam, from there i am going to attempt a lost foam cast which will be fun and do doubt take me a few attempts. so i am currently roaming the hard rubbish collections pulling heat sinks from old computers to melt down. 

also do you see a problem with sealing the front of the array infront of the lenses with acrylic? i figure it will make it easier to water proof and for cleaning rather than trying to fit it to the individual lenses, ill be using the laser cutters at uni for that as well.


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## Lynx_Arc (May 24, 2011)

monkers said:


> i hadnt even looked at them, and your right. looks like id get way more performance per driver for less $. so i think they will be the ones i cant seem to find any lenses around 10degrees though http://www.ledil.com/node/2/ they all say comming soon..
> 
> so im currently designing the housing and heat sink on cad so i can use universities cnc router transfer to blue foam, from there i am going to attempt a lost foam cast which will be fun and do doubt take me a few attempts. so i am currently roaming the hard rubbish collections pulling heat sinks from old computers to melt down.
> 
> also do you see a problem with sealing the front of the array infront of the lenses with acrylic? i figure it will make it easier to water proof and for cleaning rather than trying to fit it to the individual lenses, ill be using the laser cutters at uni for that as well.


 
I don't really know much about cree lenses but I don't see anything wrong with sealing them in as long as you can take it apart if needed and/or make sure everything has a chance to "breathe" fresh air after you put it together so no fumes fog things up as a completely sealed system has nowhere for chemical fumes from solder and cleaning agents and such to finish evaporating. 
I haven't seen much in the way of cree P7 or SSC multi die emitters being used lately I think because how the XML is doing.


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## siamese (May 26, 2011)

You should think about HID instead of the LEDs. With 24 of these LEDs you'll get maximum 15 klm with about 150W and you'll have a very big construction. You can get 100W (in reality the input power is about 100W, not the lamp power) Xenon kits for (illegal) automotive lights for about 120$ two pieces (ballast and lamp). We measured these lamps (4300K types) in a calibrated sphere and got between 7000 and 8000 lm output. I think it is even today much easier to built such a bright light by HID than by LED. 
Here are some of my measurements of Cree XM-L Leds (posted in a german mountainbike Forum):http://www.mtb-news.de/forum/showpost.php?p=8242034&postcount=1157

best regards 
Thomas


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## monkers (May 26, 2011)

siamese said:


> You should think about HID instead of the LEDs. With 24 of these LEDs you'll get maximum 15 klm with about 150W and you'll have a very big construction. You can get 100W (in reality the input power is about 100W, not the lamp power) Xenon kits for (illegal) automotive lights for about 120$ two pieces (ballast and lamp). We measured these lamps (4300K types) in a calibrated sphere and got between 7000 and 8000 lm output. I think it is even today much easier to built such a bright light by HID than by LED.
> Here are some of my measurements of Cree XM-L Leds (posted in a german mountainbike Forum):http://www.mtb-news.de/forum/showpost.php?p=8242034&postcount=1157
> 
> best regards
> Thomas


 
are you talking about the p7 or the xm-l?


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## siamese (May 26, 2011)

Sorry I ment 15 klm with 24 XM-L at about 240 watts not 150 watts. Forgot the P7!


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## monkers (May 26, 2011)

*are they telling the truth?*

okay so iv been doing some lurking, and well i cant work out how visionx comes up with their output number (lm)

so this is the cross section and to me it looks like they use cree Xlamp Mc-E http://visionxsuperstore.com/images/products/detail/doubleevoprime_open_760.1.jpg

which to my understanding only run at 700lm 
http://www.cree.com/products/pdf/XLampMC-E.pdf


and here on their page they claim that it puts out 6,880lm for the 8 leds.
http://www.visionxusa.com/LED-Doubl...UBLE_STACK_|_40_DEGREE_WIDE/product_info.html

well to me 8x Mc-E only = 5,600lm then -90% for driven power and -90% for optics efficiency and i get only 4,536lm

correct me if im wrong but does that seem a little odd to anyone?


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## monkers (May 26, 2011)

yeh i figured

800lm is alot different to the "Delivers 1000 lumens at 100 lumens per Watt" they say on the page


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## siamese (May 26, 2011)

You have to be very careful with lumen from datasheets. I mesured many LEDs in a calibrated ulbricht sphere at the University where I work and especially the cree XP-G had a big difference (about 100lm less)! In this (very long) german IBC thread I posted all my results:
http://www.mtb-news.de/forum/showthread.php?t=298107

Regards
Thomas


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