Yet another XML video light request fo suggestions

Zeus Faber · Jan 16, 2013

Hi all,

My first real post here, so don't shoot at the pianist.

I would like to try build a video light. The light should be used handheld by the diver/model to add some effect to my shots. I mainly dive on deep wrecks or caves.

I have the opportunity to get nearly free of cost one or two old halogen lights. They are aluminium built with a 6 mm glass and in perfect condition except the battery pack. So the idea would be to remove the reflector, drop in some custom build led module and a brand new battery pack. It's for video use so I need the largest illumination field and a strong lumen output.

This is one possible candidate to modify:

Isotecnic 50W (85mm x 160mm) it has an original battery pack made of 10x D Nimh cells.

There's a bigger model too, same shape and built but larger

Which kind of XML leds can be mounted in a round shape of 70mm? And how many lumen can be obtained?

Thank you in advance.

DIWdiver · Jan 16, 2013

Those look like great hosts. I've been keeping my eye out for a cheap Darrell Allen for an LED mod.

You can get XMLs on 16mm stars, and get 15-20 of them in a 70mm circle. At 900-1000lm each, you can do the math. You definitely want to get LEDs that are mounted on stars, as it makes assembly vastly easier.

Replacing the cells with D-size LiIon cells, you'd have a pack with 185-220 watt-hours. But 32600 cells (D size) have poor volumetric energy density. Fill the same volume with 18650 cells and you'd get more energy. And of course that's on the smaller light. Taking advantage of available space, you might find some really good LiPo cells too.

If you're going to make a 15,000 lm light, you will definitely need to pay careful attention to heat dissipation. The body looks like aluminum, which is great. The LEDs will need to be mounted on a thick aluminum plate, which will have to make very good thermal contact with the body of the light. Then you need to make sure you only operate it in the water, unless you have thermal protection for the LEDs.

You'll also need drivers. Though they aren't cheap, the best drivers are probably from Taskled. You could cheap out and buy some things from Kaidomain or Dealextreme or elsewhere for a few bucks, but why risk it. You're already going to be spending a bundle on LEDs and batteries. There are also some other good drivers around, like Der Wichtel and some other maker in Germany whose name I can never remember. Der Wichtel is very low on features, and I can't read the German data sheets very well.

lucca brassi · Jan 16, 2013

http://pcb-components.de/index.php

jspeybro · Jan 17, 2013

I always return to this site to find out what I can fit in a host.
http://hydra.nat.uni-magdeburg.de/packing/cci/d1.html
The interesting number is the ratio. for a certain diameter of the led star, multiply it with the ratio of a certain configuration to see if it will fit the overal diameter.
There is a nice board available at cutter for lots of light with 8 XML's:
http://cutter.com.au/products.php?cat=Leds+on+40mm+Round+MCPCB
They seem to come in different color tints now as well.
350xfire used this for a videolight so he'll be able to give you some hints here.

the good drivers are already mentionned.
Johan

Zeus Faber · Jan 17, 2013

Thank you all for your kindly replies.
I'l try to define the project a little better. Please correct me.

About Led...

15000 Lumen is more than I was thinking

Maybe for my first mod (on the small light) a 6000/7000 Lumen would be enough.
I was reading about Cree XM-L T6 or U2 led. I saw single LED on star or a ready to use 7x XML-T6 or U2 on a copper pcb. What's the difference using single stars or a single 7 led pcb? Except overall dimension of course. Maybe the 7x Led copper pcb dissipates heat better?

About driver...

To use 7 XM-L Led in series at 3A I would need a forward voltage of 28V. I don't know how if it's easy to get here in Europe Taskled drivers; could you point me to a good driver brand here in Europe?
I was reading about different types of drivers (buck, boost, step up). If I understood correctly it mainly depends on the input voltage available (battery pack).
Assuming I do not have space constraint, what's the best solution for that 7x Led array trying to avoid to stress 18650 cells?
I'm a newbie on this but I read that some drivers regulate the current via PWM and that its frequency could affect ("beat") the quality of the output light. (I will use it for video so I need continuous flux ). A 1 hour operating time would be enough.

About switch.
The hosting light comes with a 10A robust mechanical switch that I would like to use. Reading some driver datasheets it seems that I'm forced to use a different kind of switch.

Regarding heat dissipation I have an aluminium bar with a diameter of 100mm. I would machine it with a lathe exactly to the inner light tube diameter (81mm). I should have about 20mm of thickness available. I hope it's enough.

Thank you in advance

Zeus Faber · Jan 17, 2013

jspeybro said:
I always return to this site to find out what I can fit in a host.
http://hydra.nat.uni-magdeburg.de/packing/cci/d1.html
The interesting number is the ratio. for a certain diameter of the led star, multiply it with the ratio of a certain configuration to see if it will fit the overal diameter.

Wow very useful. If I understand it correctly, a 9 circles in a circle, has a radius of 0.2767.
My light inner diameter is 80mm, hence 80mm * 0.2767 = 22.136mm.

A single XM-L U2 copper pcb has a diameter of 16mm so plenty of space even with 9 stars.

Given that I want the maximum flood available I have to mount the stars as much as possible near the front glass.

Thank you.

jspeybro · Jan 17, 2013

I'm in Europe as well. Taskled works just fine. Just a quick email to order. Pay via paypal and you're done. except if you live in Italy apparently...
Taskled drivers are switching fast enough (PWM frequency) as far as I heard and have been used for video by many others.
XML's on stars are useful for projects with only a small number of LEDs with reasonable space and for use with optics for single emitters.
The boards with 7 leds typically use 1 optic that has 7 lenses in it. These are typically on the small side so don't focus very well. In your case you probably won't use optics at all so you can use many leds on a single board. Cutter.com.au has a nice selection of boards. led-tech.de also has nice options and ships very fast.

I wouldn't worry about the switch. looks fine to me.

lucca brassi · Jan 17, 2013

TaskLed post comes in EU very quickly , so no problems . I have mentioned PCB- Components before , I have upgraded some microscopes lights from halogen (21V AC,150W) with these kits , also used option to rise up driver frequency for video via PWM Nano from 200Hz to 2000Hz (works fine on 5Mpix microscope camera ).

Regarding heat dissipation I have an aluminium bar with a diameter of 100mm. I would machine it with a lathe exactly to the inner light tube diameter (81mm). I should have about 20mm of thickness available. I hope it's enough.

81mm is huge diameter . In that case I would put yours leds close to outside walls not thick Alu , but thin Cu ( will add sketch later )

- point is to put leds on outside wall to get better thermal path direct to outside
- Cu for better thermal conuctivity (twice of Al)

- with large hole in the middle (you interrupt internal heating between leds)
- you also lower common mass because of heavier insert

-[I put just for idea another powerful focus light for long distances (wrack , cave )]

IMO I think that Al is satisfactory for backups or something like Maglite but in case of video no way.
also think and calculate buoyancy of that light ( you want it neutral ?)

- I would do ring with 6 XML
http://pcb-components.de/index.php?...category_id=6&option=com_virtuemart&Itemid=64

- light control http://pcb-components.de/index.php?...category_id=8&option=com_virtuemart&Itemid=64

- focus with separated driver depends from led type & optics

Zeus Faber · Jan 17, 2013

lucca brassi said:
TaskLed post comes in EU very quickly , so no problems . I have mentioned PCB- Components before , I have upgraded some microscopes lights from halogen (21V AC,150W) with these kits , also used option to rise up driver frequency for video via PWM Nano from 200Hz to 2000Hz (works fine on 5Mpix microscope camera ).

Unfortunately I discovered that Taskled doesn't ship anymore to Italy for Italian shipping service being the worst in Europe

So I have to find out another source for good drivers. Anyway I'm still scratching my head on a correct driver...
I think I have the space for 12x 18650 cells. So if I want reach the 7x XM-L correct Fv I should stay between 20V and 28V.
I could do a 6S2P getting a max 25,2 when fully charged.
But then... which driver? :thinking:

81mm is huge diameter . In that case I would put yours leds close to outside walls not thick Alu , but thin Cu ( will add sketch later )

If I use several stars and I put them colse outside wal I'm afraid I will limit the flood getting a nasty round shadow.

jspeybro · Jan 17, 2013

you can also use a boost driver. in that case the input voltage does not need to be higher than the total voltage of the LEDs.

Here are some possibilities (first 2 in the list):
http://www.videofoundry.co.nz/ianma...odes=any&size_min=&size_max=&order=drivername

for example, using the one from int'l outdoor (p-545), you can probably use 3 18650's in series (3S4P).

is the italian post service that bad?

Zeus Faber · Jan 17, 2013

jspeybro said:
you can also use a boost driver. in that case the input voltage does not need to be higher than the total voltage of the LEDs.

Here are some possibilities (first 2 in the list):
http://www.videofoundry.co.nz/ianma...odes=any&size_min=&size_max=&order=drivername

for example, using the one from int'l outdoor (p-545), you can probably use 3 18650's in series (3S4P).

is the italian post service that bad?

I will study your link tonight

Yes, I found several online shops that refuse to ship in Italy thorugh the normal postal service. Lately, to avoid problems I'm buying only form sellers who use private courier like UPS or similar. Probably Taskled uses just plain posta services so he's having problems...

Bye

jspeybro · Jan 17, 2013

perhaps you can ask George from taskled if he can send using UPS, Fedex,TNT,... but it will be more expensive I guess. better first decide on the driver

andrew_t · Jan 17, 2013

why don't you try one of those drivers?
http://www.ledsales.com.au/catalog/...ducts_id=939&zenid=9pq4ejr8q23qqq9ovnauvrlqk2

Zeus Faber · Jan 18, 2013

lucca brassi said:
- point is to put leds on outside wall to get better thermal path direct to outside
- Cu for better thermal conuctivity (twice of Al)

- with large hole in the middle (you interrupt internal heating between leds)
- you also lower common mass because of heavier insert

-[I put just for idea another powerful focus light for long distances (wrack , cave )]

IMO I think that Al is satisfactory for backups or something like Maglite but in case of video no way.
also think and calculate buoyancy of that light ( you want it neutral ?)

- I would do ring with 6 XML
http://pcb-components.de/index.php?...category_id=6&option=com_virtuemart&Itemid=64

- light control http://pcb-components.de/index.php?...category_id=8&option=com_virtuemart&Itemid=64

- focus with separated driver depends from led type & optics

Thank you all for your information. I hope to get the host light in my hand soon drawing some sketch with correct measures. I'm trying to get all the components here in Europe. Pcb-Components has nice and reliable devices...

I would like having the widest flood and I do not need different power selection. Just the sun

So far my choices would be:

7-x-CREE-XM-L-U2-on-copper-round-PCB (applying it on a 81mm copper plate. Thickness depends on available space)

Led Senser Xtreme 200 2050mA 6-30V from pcb-components. It can drive up to 3A. I would apply it on the rear of the copper plate.

The battery pack would be a 5S2P or maybe 5S3P. The host light originally had 10 NiCd cells. There should be enough space. (I will be more exact as I get it)

The driver manual english translation is not very clear about getting 3A. It's clear that I have to solder a resistor in parallel to the existing resistance which sits at the 200mA soldered bridge. It's not clear "Unsolder the coil, it is advantageous to work better" :thinking:
I mailed them asking more info...

That driver accepts a 7A max current. I tried to do some math...
In the worst case with discharged batteries on a 5S I would have about 15V. On the driver manual I do not see efficiency at 3A but I guess at least 90%.
Hence:

Output power = 23,4V * 3A = 70W (each XM-L U2 has a Vf of 3.35@3A)
Input power = 70W/0.9 = 78W hence 8W are dispersed as heat.
Input current = 78W / 15V = 5.2A

With that battery pack and these data I should stay well within that driver parameters. Are my calculations correct? Should I take in account Led and driver voltage drop?

Which kind of operating time I could expect with a 5S2P?

If my math is correct I would start grabbing my credit card...

If everything works as expected a later addiction would be changing the original mech switch with a piezo one.

Thank you in advance.

jspeybro · Jan 18, 2013

Zeus Faber said:
The driver manual english translation is not very clear about getting 3A. It's clear that I have to solder a resistor in parallel to the existing resistance which sits at the 200mA soldered bridge. It's not clear "Unsolder the coil, it is advantageous to work better" :thinking:
I mailed them asking more info...

it says that you need to solder a 0.1ohm resistor in parallel with the resistor that is in the marked location for 200mA. Because the inductor is so big, it will most likely be very difficult to solder the resistor because the inductor is in the way.
The inductor is soldered in two places to the board. It is often enough to unsolder 1 contact to move it out of the way CAREFULLY. you don't want to break it ;-)

Zeus Faber · Jan 18, 2013

R: Yet another XML video light request fo suggestions

jspeybro said:
it says that you need to solder a 0.1ohm resistor in parallel with the resistor that is in the marked location for 200mA. Because the inductor is so big, it will most likely be very difficult to solder the resistor because the inductor is in the way.
The inductor is soldered in two places to the board. It is often enough to unsolder 1 contact to move it out of the way CAREFULLY. you don't want to break it ;-)

Ah! OK

Any problem on my selection and math?

lucca brassi · Jan 22, 2013

I have remember actually H2O Doc made something like I have made draw before http://www.candlepowerforums.com/vb/showthread.php?322790-4-XRE-XML-dive-light

jspeybro · Jan 22, 2013

Re: R: Yet another XML video light request fo suggestions

Zeus Faber said:
Ah! OK

Any problem on my selection and math?

Math looks fine.
regarding opering time, you need the capacity of the cells.
If you use 18650's of let's say 2200mAh, and e.g. a 5S2P batterypack as you suggest, you'll have a pack with about 18.5V (3.7V*5) with a capacity of 4.4Ah (2*22200mAh). if you multiply these numbers you get 18.5V*4.4Ah=81.4Wh.
Your light draws about 78W of power, so that gives you 81.4Wh/78W=1.04h. you'll get about 1 hour burn time.

Zeus Faber · Jan 22, 2013

Re: R: Yet another XML video light request fo suggestions

jspeybro said:
Math looks fine.
regarding opering time, you need the capacity of the cells.
If you use 18650's of let's say 2200mAh, and e.g. a 5S2P batterypack as you suggest, you'll have a pack with about 18.5V (3.7V*5) with a capacity of 4.4Ah (2*22200mAh). if you multiply these numbers you get 18.5V*4.4Ah=81.4Wh.
Your light draws about 78W of power, so that gives you 81.4Wh/78W=1.04h. you'll get about 1 hour burn time.

Ok thanks perfect! I hope to be able to have 6S2P. A higher input voltage fro this driver it's better to lower the drawn current.

lucca brassi said:
I have remember actually H2O Doc made something like I have made draw beforehttp://www.candlepowerforums.com/vb/showthread.php?322790-4-XRE-XML-dive-light

Nice thread. I see there are a lot of nice thread I didn't see. Actually that light seems to have a tight beam....

BTW I was reading this thread abotu the expensive Sartek light. I saw one of them underwater and it's incredible.

http://www.candlepowerforums.com/vb/showthread.php?330467-SARTEK-VIDEO-LIGHT&highlight=sartek

The nice thing is that it's driven by a normal 12V battery pack. Essentially the same I use in my canister.
Which kind of led ad driver is ti using?

Bye

jspeybro · Jan 22, 2013

Re: R: Yet another XML video light request fo suggestions

Zeus Faber said:
Ok thanks perfect! I hope to be able to have 6S2P. A higher input voltage fro this driver it's better to lower the drawn current.

or you could put more cells in parallel to lower the current per string of cells. 5A from a 2P pack is about 2.5A per string. 3P will be 1.7A per string.

Yet another XML video light request fo suggestions

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