White LED, crazy idea... or not?

Mike Rehmus · August 24th, 2004, 07:53 PM

Received the LED light fixture (MR16-42-21W-014M) and a lamp socket (hard to find) and have found what will be the first enclosure.

Think I"m just going to power it straight from my NRG battery belt for now using a 4-pin XLR cable. Later I may mess around with two Sony LiON batteries in series to power it.

The lamp head will weigh about 6 oz without the cable.

Expect to have it operational by next week.

Pictures at 11

Mike Rehmus · August 26th, 2004, 09:23 AM

Quick update.

Put the lamp on my 65 watt, 12 volt NRG battery belt to check battery life.

That was 24 hours ago. Looks like it will run a minumum of another 24 hours. Guess I can downsize the battery!

Les Dit · August 26th, 2004, 03:12 PM

You guys know that compact fluorescent bulbs make more light than an LED , watt for watt.
They make 12V compact fluorescent bulbs too. High frequency ballasts are recommended.

LED's might be great for small lights, or where damage might be a concern.

-Les

Mike Rehmus · August 26th, 2004, 04:36 PM

The problem with flo's is that they are too large to comfortably fit on top of a camera. Plus they require a high voltage power supply which LEDs do not. Energy efficiency isn't the ultimate goal.

LEDs tend to project their light forward since they have or can have a lens. So they tend to throw columnated light, sort of like a fresnel. Sharp fall-off on the edges of the beam. This is an advantage since I don't need a reflector to recapture the light that would otherwise escape to the side and rear.

Lots of reasons why LEDs are superior for my application. And I think, perhaps, even for studio use. I've now seen a light panel thinly populated with white LEDs and of a size to be a soft and broad light source that can be powered by something like a NP-1B for an hour or two. Or from a small wall wart.

You literally could make a broad LED light by pushing the LEDs through Foam board and then wiring up the pins to accomodate the power supply you want to use.

Need incandescent and daylight balance? Just make the panel with both 3500 K and 6000K or 7000K LEDs. Turn on what you want.

Matter of fact, if you wanted to spend the money for a flexible circuit board (expensive), you could roll your LED light panels up and put them in a tube for shipping. Then pin them up or hang them from a clothes hanger for use.

Taking it to the extreme, Because LEDs can be very small, how about the equivalent of wall paper that you glue on a wall? Now you have a very broad and soft light.

Brett Erskine · August 26th, 2004, 04:56 PM

Have you looked into tiny DC to DC converters that take you from 7.2V to aprox. 14V?

Mike Rehmus · August 26th, 2004, 05:05 PM

Not yet. I'm probably going to power the lamp from my battery belt for the next exhibiton or from the power tap on my DSR-300 camera.

Got a source for Sony LiON battery sockets? I'd hate to have to build them after examining the spring-loaded blades that socket into the female pins on the batteries.

Of course I could just disassemble one of my battery chargers!

Brett Erskine · August 27th, 2004, 09:16 PM

Haven't looked for thoughs Sony batteries but I was able to find one for my DVX100 battery. Im looking all over the place for that DC to DC converter. I need to take 7.2V / 1600mAh and take it up to around 14V at a 12w/1 Amp draw for the LED lights. Anyone know where to find one?

Giroud Francois · August 28th, 2004, 05:25 AM

try
http://www.power-one.com/ (former swiss melcher company)
while converting from 7.x volt seems not very easy to find (usual range are 3V, 5V 12V)
see http://www.datel.com/data/power/uwr14-20wa-series.pdf

Dan Euritt · August 28th, 2004, 01:48 PM

dc-to-dc converters can be real inefficient... avoid if at all possible.

i would be looking to power a small led panel with some kind of off-the-shelf nimh battery solution, maybe a d-cell setup... nimh is phenomenal, it retains full voltage during the discharge curve, and it's gotten real cheap in the standard flashlight battery sizes.

Mike Rehmus · August 28th, 2004, 06:15 PM

I just bought a LiON pack that will work very nicely. Should run the lamp about 30 hours or so.

I couldn't find a DC to DC converter that would accept 6 volts in, a voltage which would be convenient to supply.

Brett Erskine · August 29th, 2004, 02:00 AM

Yeah the DC to DC may be a dead end. I knew that DC to AC converter were ineffecient but didnt know DC to DC converters were as well. Can anyone else varify this? If so the only other two options I have is to run it off 2 DVX100 batteries or find a new Lith-Ion battery thats 14V. What a shame. I was really hoping to use just one DVX battery.

Jos Svendsen · August 29th, 2004, 02:09 AM

I sure hope that a bright (Sic transit ..) manufacturer reads this. There should be basis for some killer producs - an ambrella with build in LEDs for a collapsible softlight. The possibles are very interesting.

rgds

Giroud Francois · August 29th, 2004, 02:24 AM

lots of laptop batterie are 14.4v. You could try to find an broken one that just have the battery and the charger still working.

Mike Rehmus · August 29th, 2004, 11:08 AM

LEDTronics is very specific that the input voltage must not be above 14 VDC. It there is no tolerance above that (I'd believe they have something of a safety factor) then the 14.4 LiONs aren't great.

I have three Sony V-Mount LiIONs for my DSR-300 but they are way out of line with regard to cost. So I'll go with the 12 V LiON pack for $90 (with charger and cables) as the power supply. IT has 4,000 milliamps of capacity which is around 40 hours of light or so. I should have it in hand sometime this week and will report.

What I'd really like to find is some rechargable LiON pancake batteries of about 2" diameter so I could stack them.

Laptop batteries are quite expensive (new) and rarely have a stand-alone charger. Plus they require an enclosure or they are a bit fragile. Plus the issue of making a power connector.

Mike Rehmus · August 29th, 2004, 11:10 AM

<<<-- Originally posted by Jos Svendsen : I sure hope that a bright (Sic transit ..) manufacturer reads this. There should be basis for some killer producs - an ambrella with build in LEDs for a collapsible softlight. The possibles are very interesting.

rgds -->>>

But you don't need the umbrella, just a set of ribs to hold the LEDs out in a nice pattern. And that's if you don't mind carrying a flat sheet of plastic in which the LEDs are mounted.

BTW, when I pulled the plug on the lamp, it had run for 48 hours on my battery belt. According to the voltage left in the belt, it probably would have run for more than another 24 hours. The LED indicator on the belt had just tripped down to the second green segment.

August 24th, 2004, 07:53 PM	#31
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Received the LED light fixture (MR16-42-21W-014M) and a lamp socket (hard to find) and have found what will be the first enclosure. Think I"m just going to power it straight from my NRG battery belt for now using a 4-pin XLR cable. Later I may mess around with two Sony LiON batteries in series to power it. The lamp head will weigh about 6 oz without the cable. Expect to have it operational by next week. Pictures at 11 __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

August 26th, 2004, 09:23 AM	#32
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Quick update. Put the lamp on my 65 watt, 12 volt NRG battery belt to check battery life. That was 24 hours ago. Looks like it will run a minumum of another 24 hours. Guess I can downsize the battery! __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

August 26th, 2004, 04:36 PM	#34
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	The problem with flo's is that they are too large to comfortably fit on top of a camera. Plus they require a high voltage power supply which LEDs do not. Energy efficiency isn't the ultimate goal. LEDs tend to project their light forward since they have or can have a lens. So they tend to throw columnated light, sort of like a fresnel. Sharp fall-off on the edges of the beam. This is an advantage since I don't need a reflector to recapture the light that would otherwise escape to the side and rear. Lots of reasons why LEDs are superior for my application. And I think, perhaps, even for studio use. I've now seen a light panel thinly populated with white LEDs and of a size to be a soft and broad light source that can be powered by something like a NP-1B for an hour or two. Or from a small wall wart. You literally could make a broad LED light by pushing the LEDs through Foam board and then wiring up the pins to accomodate the power supply you want to use. Need incandescent and daylight balance? Just make the panel with both 3500 K and 6000K or 7000K LEDs. Turn on what you want. Matter of fact, if you wanted to spend the money for a flexible circuit board (expensive), you could roll your LED light panels up and put them in a tube for shipping. Then pin them up or hang them from a clothes hanger for use. Taking it to the extreme, Because LEDs can be very small, how about the equivalent of wall paper that you glue on a wall? Now you have a very broad and soft light. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

August 26th, 2004, 05:05 PM	#36
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Not yet. I'm probably going to power the lamp from my battery belt for the next exhibiton or from the power tap on my DSR-300 camera. Got a source for Sony LiON battery sockets? I'd hate to have to build them after examining the spring-loaded blades that socket into the female pins on the batteries. Of course I could just disassemble one of my battery chargers! __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

August 28th, 2004, 06:15 PM	#40
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	I just bought a LiON pack that will work very nicely. Should run the lamp about 30 hours or so. I couldn't find a DC to DC converter that would accept 6 volts in, a voltage which would be convenient to supply. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

August 26th, 2004, 03:12 PM	#33
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	You guys know that compact fluorescent bulbs make more light than an LED , watt for watt. They make 12V compact fluorescent bulbs too. High frequency ballasts are recommended. LED's might be great for small lights, or where damage might be a concern. -Les

August 26th, 2004, 04:56 PM	#35
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Have you looked into tiny DC to DC converters that take you from 7.2V to aprox. 14V?

August 27th, 2004, 09:16 PM	#37
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Haven't looked for thoughs Sony batteries but I was able to find one for my DVX100 battery. Im looking all over the place for that DC to DC converter. I need to take 7.2V / 1600mAh and take it up to around 14V at a 12w/1 Amp draw for the LED lights. Anyone know where to find one?

August 28th, 2004, 05:25 AM	#38
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	try http://www.power-one.com/ (former swiss melcher company) while converting from 7.x volt seems not very easy to find (usual range are 3V, 5V 12V) see http://www.datel.com/data/power/uwr14-20wa-series.pdf

August 28th, 2004, 01:48 PM	#39
Dan Euritt Trustee Join Date: Mar 2004 Location: Carlsbad CA Posts: 1,132	dc-to-dc converters can be real inefficient... avoid if at all possible. i would be looking to power a small led panel with some kind of off-the-shelf nimh battery solution, maybe a d-cell setup... nimh is phenomenal, it retains full voltage during the discharge curve, and it's gotten real cheap in the standard flashlight battery sizes.

August 29th, 2004, 02:00 AM	#41
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Yeah the DC to DC may be a dead end. I knew that DC to AC converter were ineffecient but didnt know DC to DC converters were as well. Can anyone else varify this? If so the only other two options I have is to run it off 2 DVX100 batteries or find a new Lith-Ion battery thats 14V. What a shame. I was really hoping to use just one DVX battery.

August 29th, 2004, 02:09 AM	#42
Jos Svendsen Major Player Join Date: Mar 2004 Location: Copenhagen, Denmark Posts: 221	I sure hope that a bright (Sic transit ..) manufacturer reads this. There should be basis for some killer producs - an ambrella with build in LEDs for a collapsible softlight. The possibles are very interesting. rgds __________________ ---------------------------- 12c41 JOS. Svendsen

August 29th, 2004, 02:24 AM	#43
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	lots of laptop batterie are 14.4v. You could try to find an broken one that just have the battery and the charger still working.

August 29th, 2004, 11:08 AM	#44
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	LEDTronics is very specific that the input voltage must not be above 14 VDC. It there is no tolerance above that (I'd believe they have something of a safety factor) then the 14.4 LiONs aren't great. I have three Sony V-Mount LiIONs for my DSR-300 but they are way out of line with regard to cost. So I'll go with the 12 V LiON pack for $90 (with charger and cables) as the power supply. IT has 4,000 milliamps of capacity which is around 40 hours of light or so. I should have it in hand sometime this week and will report. What I'd really like to find is some rechargable LiON pancake batteries of about 2" diameter so I could stack them. Laptop batteries are quite expensive (new) and rarely have a stand-alone charger. Plus they require an enclosure or they are a bit fragile. Plus the issue of making a power connector. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

August 29th, 2004, 11:10 AM	#45
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	<<<-- Originally posted by Jos Svendsen : I sure hope that a bright (Sic transit ..) manufacturer reads this. There should be basis for some killer producs - an ambrella with build in LEDs for a collapsible softlight. The possibles are very interesting. rgds -->>> But you don't need the umbrella, just a set of ribs to hold the LEDs out in a nice pattern. And that's if you don't mind carrying a flat sheet of plastic in which the LEDs are mounted. BTW, when I pulled the plug on the lamp, it had run for 48 hours on my battery belt. According to the voltage left in the belt, it probably would have run for more than another 24 hours. The LED indicator on the belt had just tripped down to the second green segment. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!