SSC P7 and driver question

[1-3-2-4]

Hi I'm new here and I ordered a few things for a project I want to make which is very bright reverse lights for a car.

This is a break down of what I ordered...

2 SSC P7's

2 40x40x18mm heatsink with adhesive tape

1 power Puck (1000mA version)

1 40x18mm 14,000 RPM fan to have on hand for testing and cooling if need be.

from what someone else told me driving the P7 with the Power Puck at 1A would only get me around 250lm?

My question is where can i find a 2.8A driver? the driver would be connected to the connection to the reverse lights

 

[Bimmerboy]

Hi, 1-2-3-4, and :welcome:

Coincidentally, I just checked in here after perusing the Shoppe's section of the forum, and spotted ya' over there too. As you may be aware, driver solutions for multi-die emitters (P7, and MC-E) are still being perfected, especially those capable of driving more than one. We're getting close!

For P7 output, check out jtr1962's numbers in his White LED lumen testing thread. At 1A it gave approx. 329 lumens. But if memory serves me, I believe the Powerpuck actually delivers less than the 1A it's rated for (850mA under most conditions?). You may want to follow up to see if that's the case as I won't be winning any memory contests anytime soon. If so, according jtr you should get slightly above 270 lumens. And then you'll need two of them, one for each P7.

However, there's the problem of safety, reliability, and possibly not passing inspection if a mechanic happens to wonder why the reverse lights are blazing up half the garage... lol.

As for reliability, Wayne points out in the Shark Buck thread "For an auto application you should add the standard input protection for surge, reverse battery protection and any other protection required. Surge used to be a voltage spike of 60V. Not sure what todays specificatiosn are."

They may be better now, but I believe even todays cars still have pretty dirty, spikey electrical systems.

Safety-wise, the first thing I thought of upon reading the first sentence of your post was my experience this past Thusday night. I had pulled up to a curb, and hadn't gotten out of the car yet when someone I know pulled into the spot in front of me. He had to back up a bit to straighten out, and man, those were some damn bright reverse lights. They're mounted high as well. I think it was a fairly new Lincoln, but honestly couldn't see the trunk through the lights, and it destroyed whatever night adaptation I had for a couple minutes. I got out and jokingly commented on them while pretending to stumble around blind.

Moral of the story is... you might want to reconsider sending 550 lumens or more from the rear of your car, or at least design the setup to point slightly downward, or have them on a manual switch for emergency use only as there's a possibility of creating a real hazard if someone behind you gets blasted by two P7's, and continues to operate a vehicle. Likely scenario's might include backing out of a parking space while someone waits for you. Next thing you know, that person is mowing down Christmas-time shoppers, and smashing into other cars. Hehe... I may be exaggerating a bit, but you get the point.

This idea might be better used toward a different purpose. Perhaps a trunk light for portable, night time barbequing! Cooler for the meat, hibachi, bag of coals, and a P7 to flood the work area... instead of pissing everyone off with reverse lights, you'll be the most popular guy in town!... LOL.

 

[1-3-2-4]

Thanks for the welcome, well my power puck came in today but the P7's have not shipped yet I was under the impression that I could drive two P7's with one Power puck..

also I would be pointing the lights down a little the rear window is tinted, and I understand about the shark I rather have it perfected then not working right.

 

[yellow]

forget the shark, it is a step-up driver for series conected led
(which is the better way of driving them anyway, but You want P7, so ...)

there are a few drivers linked in here, from Kaidomain I think. Should be able to drive the parallel wired led with 2.8-3 A from a wide input Voltage, maybe they fit Your needs.



You can use any driver that drives a wite led with a given power, but You need 2.8 A for each P7 to receive their most possible output.
A Buckpuck seems to give the specified output, no matter how much higher the base voltage is, so Your 1000 mA Puck gives 1 A (what a surprise).
Of course You can drive both led with it, but each now gets just 500 mA.
(when understanding the descripion correct, it might be possible to wire the P7s in series and still receive 1 A, as the BuckPuck seems to be a current fixing regulator. Far from the 2.8 A needed but still very bright and one circuit for both led)

 

[1-3-2-4]

forget the shark, it is a step-up driver for series conected led
(which is the better way of driving them anyway, but You want P7, so ...)

there are a few drivers linked in here, from Kaidomain I think. Should be able to drive the parallel wired led with 2.8-3 A from a wide input Voltage, maybe they fit Your needs.



You can use any driver that drives a wite led with a given power, but You need 2.8 A for each P7 to receive their most possible output.
A Buckpuck seems to give the specified output, no matter how much higher the base voltage is, so Your 1000 mA Puck gives 1 A (what a surprise).
Of course You can drive both led with it, but each now gets just 500 mA.
(when understanding the descripion correct, it might be possible to wire the P7s in series and still receive 1 A, as the BuckPuck seems to be a current fixing regulator. Far from the 2.8 A needed but still very bright and one circuit for both led)

So it's a step up from a series.. well how about I just buy two shark bucks then?

also I saw that driver at Kaidomain but that's one of those multi-mode drivers right? since these LED's are going into a car's tail lights I just need it to run at full power mode.. also some reviews I have seen said if it overheats it goes to low power mode but how much heat does it give off?

it's not that much of an issue because I have been thinking if I need to have fans over the heatsinks of the LED's anyways on a temp controled circuit. I'm not looking to drive the SSC P7 at it's max output just for longetivy sake.

 

[evilc66]

You may not need fans if you can get a heatsink or a plate with enough mass behind the LEDs. They aren't going to be on for very long, so it will take a while for a large thermal mass to heatsoak. Plus, you are underdriving the LEDs anyway.

A better option might have been a Cree XR-E, or SSC P4 series LED. You will be running about the same current and output as the P7 for considerably less cost. You also have greater options on optics. An oval beam optic might be useful in this application to shape the light low and wide.

There are also more options in drivers at that point too.

 

[1-3-2-4]

You may not need fans if you can get a heatsink or a plate with enough mass behind the LEDs. They aren't going to be on for very long, so it will take a while for a large thermal mass to heatsoak. Plus, you are underdriving the LEDs anyway.

A better option might have been a Cree XR-E, or SSC P4 series LED. You will be running about the same current and output as the P7 for considerably less cost. You also have greater options on optics. An oval beam optic might be useful in this application to shape the light low and wide.

There are also more options in drivers at that point too.

I ordered 2 40x40 x18mm heat sinks for the LED I think it should be good without a fan, no?

I thought about a XR-E but I could find nothing other then series version..

 

[yellow]

So it's a step up from a series.. well how about I just buy two shark bucks then?

nope, You have Your vehicles system with 12 V, and a led that runs on 3.7 Volts.
Or two of them in series, making 7.4 V.
Anyway it is step-down, the Shark is completely useless with that situation.

The original idea of a BuckPuck 1000 and both P7 wired in series sounds best to me
(single output, rugged, ..., if there are even more efficient drivers available --> who cares? It is no battery powered application)
I think it will be more than bright enough, the sinks might also be enough for short bursts (as is usual for reverse light).

...about an MC-E (!) but cant find anything other than series version

... which is the safe way to drive multiple led, but that is not our topic now.

With MC-E it were: one SHARK for each led
Voltage car: 12 V, voltage Led: 14.8-16 V --> step-Up
You could set the sharks at the output You want.
more expensive, imho not necessary.

 

[1-3-2-4]

but then again each LED is only getting 500mA which is a far cry from at least 2A I was trying to get for each... 500mA each I don't think would be that much brighter then a 12V 1156 bulb.

 

[yellow]

nono, You got me wrong.
as long as the "needed" voltage is lower than the income voltage, the BuckPuck gives its output.
when You power one P7 with it, it drives this one with 1000 mA,
when You wire the 2 P7s in series, then the BuckPuck still drives these with 1000 mA
(that setup is: "+" led from Buckpuck to "+" 1st. P7, "-" 1st P7 to "+" 2nd P7, "-" 2nd P7 to "-" BuckPuck. wired in series)

only when wired in parallel each led sees just half of the 1000 mA
("+" Led from BuckPuck to "+" 1st P7 and to "+" 2nd P7, "-" 1st and "-" 2nd P7 to "-" BuckPuck)


let me try this explanation:
when wiring in series, You only have a single wire from driver to led one, further on to led two, back to driver. When driver gives a certain current, this is the same at every part of the single wire. Each led gets the full 1000 mA.

wiring in parallel, You have two wires. One from driver to led on and back the 2nd wire from driver to 2nd led and back. Here the current from the driver runs at two wires, the current the driver can give has to be devided by 2 for each wire. Each led sees only 500 mA.




(thats why wired in series is the "better" way of driving multiple led, there is always the same current at every led and the absolute current is never too high for a single emitting die. When the led are wired in parallel and driven hard, the absolute current can kill each individual die instantly. If there were one with a much lower forward voltage, this one would get much more current than the other ones and possibly get damaged quick.
But that is more a theoretical argue and not important with Your project)

 

[1-3-2-4]

well 1000mA is good but still nowhere near the P7's ratings... what about this driver from kaidomain.

http://kaidomain.com/ProductDetails.aspx?ProductID=1770

 

[TexLite]

The Shark Buck will power 2 P7's at 3A from 12V if thats what your after.

I wouldn't spend the extra $10-$20 per emitter for the P7's if I was going to run them at 1000mA.The difference between two P7's and two SSC P4's/XR-E R2's wouldn't be worth the extra cost to me.

-Michael

Edit:Forgot,that driver from KD will not work.

 

[1-3-2-4]

The Shark Buck will power 2 P7's at 3A from 12V if thats what your after.

That's all I'm after

 

[1-3-2-4]

nono, You got me wrong.
as long as the "needed" voltage is lower than the income voltage, the BuckPuck gives its output.
when You power one P7 with it, it drives this one with 1000 mA,
when You wire the 2 P7s in series, then the BuckPuck still drives these with 1000 mA
(that setup is: "+" led from Buckpuck to "+" 1st. P7, "-" 1st P7 to "+" 2nd P7, "-" 2nd P7 to "-" BuckPuck. wired in series)

only when wired in parallel each led sees just half of the 1000 mA
("+" Led from BuckPuck to "+" 1st P7 and to "+" 2nd P7, "-" 1st and "-" 2nd P7 to "-" BuckPuck)


let me try this explanation:
when wiring in series, You only have a single wire from driver to led one, further on to led two, back to driver. When driver gives a certain current, this is the same at every part of the single wire. Each led gets the full 1000 mA.

wiring in parallel, You have two wires. One from driver to led on and back the 2nd wire from driver to 2nd led and back. Here the current from the driver runs at two wires, the current the driver can give has to be devided by 2 for each wire. Each led sees only 500 mA.




(thats why wired in series is the "better" way of driving multiple led, there is always the same current at every led and the absolute current is never too high for a single emitting die. When the led are wired in parallel and driven hard, the absolute current can kill each individual die instantly. If there were one with a much lower forward voltage, this one would get much more current than the other ones and possibly get damaged quick.
But that is more a theoretical argue and not important with Your project)

I wired in series like you said however when I turned on the power LED 1 just flashed and got dim LED 2 never came on at all...

so fearing that I killed the LED die I unhooked the 2nd LED and LED 1 works as normal.

so i'm guessing one Power puck can't drive 2 P7's?

wont matter anyways since I will be getting a shark buck but just curious

 

[yellow]

hmmm.
instructions show that it is possible to set up any number of led in series and the PowerPuck will still keep the current at level
(as long as input voltage is higher than output voltage)

sounds like a short but that is next to impossible with a P7 Star.

Does led #2 work when used alone?

 

[1-3-2-4]

turns out it was a very careless mistake long story short don't try to do work when you need to sleep and be up again in 3 hours. im going to order the shark buck this week so I can drive them at 2A I won't risk running them at 3

 

[1-3-2-4]

hmmm.
instructions show that it is possible to set up any number of led in series and the PowerPuck will still keep the current at level
(as long as input voltage is higher than output voltage)

sounds like a short but that is next to impossible with a P7 Star.

Does led #2 work when used alone?

Ok I arrived home now and still it wont light.. LEd 2 will light alone

however how I have it hooked up is

PP (+) to LED1 (+) PP (-) to LED1 (-), LED1 (+) to LED2 (-) LED2 (+) to LED1 (-)

 

[yellow]

should be:
PP (+) to LED1 (+), PP (-) to LED2 (-), LED1 (-) to LED2 (+)
or, to have it easier to follow the electrical path:
PP(+) to LED1(+), LED1(-) to LED2(+), LED2(-) to PP(-)

with that wiring posted above, LED2 gets reverse current.
It should be death (if it is as sensible to reverse voltage than single emitters)

Only strange thing is, that - with that wiring:

PP (+) to LED1 (+) PP (-) to LED1 (-), LED1 (+) to LED2 (-) LED2 (+) to LED1 (-)

LED 2 should not light up but You type it does. Strange.
maybe also not LED1, as LED2 just s and all the current flows there
:thinking:
looks like the Puck has some kind of protection in, that saved both led.
Hook it up like the "revision" and both should light with full current
(when both are still intact! If one is completely dead: no light. The Puck instructions say it has a short time open load protection, so You can try that).


PS: typing this, because Your wiring will also not work with the shark, it is not series wiring, nor is it parallel.
Think of a line You draw from Puck(+) to Puck (-). When You put a led into this line, LED(+) has to look to Puck(+), Led(-) to Puck(-).
adding another led and the directions have to be the same: Led(+) has to look to Puck(+), Led(-) to Puck(-)

The difference is just the wiring:
parallel: a 2nd wire like the 1st one --> same voltage but 1/2 the current per line
series: put the led (facing the same direction as 1st one) into the line -> same current but 2 times the voltage


sorry for the long posts, in face to face communication while handling the parts, it is easy. Just by typing and reading, sounds very difficult.



[edit]
maybe its best to move You to a datasheet:
http://www.leddynamics.com/LuxDrive/datasheets/2008B-PowerPuck.pdf
figure 6 is a Series wiring, as You have to do with the 2 P7

unfortunately there is no clear parallel wiring pic, because they always have series, too
the typical application has a series wiring (the 2 led at left) and a parallel wiring with the 2 led at led (which are wired in series again)
[/edit]

 

[1-3-2-4]

I got it working but I don't understand still why I can't order a shark buck and run two P7's in series.

 

[yellow]

just because of the wiring:

however how I have it hooked up is

PP (+) to LED1 (+) PP (-) to LED1 (-), LED1 (+) to LED2 (-) LED2 (+) to LED1 (-)

Pic is better, eh

that way a step down fixed current driver like the Puck can be used
(I have no info on the Shark buck, but when it works like the boost shark, it should work also)