Angryfox        
Results 1 to 18 of 18

Thread: First time build, tube style video light

  1. #1

    Default First time build, tube style video light

    Iím working on putting together my first light and was hoping to get some help with the electronics portion. Like many of the first timers passing through here I have much more experience on the mechanical design side than the electronics. Iím looking to create something similar to Packhorseís 6000 lumen tube lights (see his signature for a link) but probably not quite that bright for my first build. I was thinking two leds per each head for about 4000 lumens. Ideal burn time would be 2-4 hours.

    Here are my thoughts, let me know what you think.

    2 LEDs per head: CREE XM-L2 T6 4C LED on Noctigon 20mm MCPCB

    Driver: This is where I am most lost, I would prefer the simplicity of a linear driver if someone could help me figure out what the ideal battery voltage would be. In his build packhorse used an 8X AMC7135 but I am having a hard time finding where to purchase these. Also canít open the datasheet, I get the basic idea but the naming conventions used with finding the correct driver is making it very difficult for me to pin down the right ones to use.

    Batteries: NiMH. I am on a budget so I need to go this route. Since I am having a hard time with the driver I am not sure yet the exact voltage and size that I need. If anyone has suggestions I would appreciate it.

  2. #2
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    2,464

    Default Re: First time build, tube style video light

    Okay, batteries first. You want 4000 lm for 2 hours minimum. That's about 40W x 2 hrs = 80 W-H.

    Since you are on a budget, AA cells typically offer the best bang for the buck, so let's look at those. At 3000 mA-H, about 1.1V average, you get 3.3 W-H per cell, and you need at least 80/3.3 = 24 cells.

    You could get by with 16-18 4/3A or C cells, 8 D cells, 6 F cells, or 4 M cells. Double those numbers to get to the upper end of your runtime expectation.

    So let's assume the low end of your battery voltage will come from 8 cells in series, or about 8V at end of discharge. Let's say the high end would be 24 cells, about 24V, though you could certainly go to 30, 40, or even 50V.

    Now let's look at the LEDs. 4 XMLs gives you three options for connection:
    - 4S1P, 12-14V at 3A
    - 2S2P, 6-7V at 6A or two separate 2S1P, 6-7V at 3A
    - 1S4P, 3-3.5V at 12A or four separate 1S1P, 3-3.5V at 3A

    Now let's think about a driver. IMHO, Cree LEDs, linear drivers, and NiMH cells make a good combination for video. Four cells in series per LED gives average efficiency around 78%. This is okay, especially as there's absolutely no issue with flicker. 7135 drivers are abundant and cheap. You could easily use four very inexpensive drivers connected to a single switch to drive four separate LEDs, or two drivers to drive 2 each. It's theoretically possible to use a 7135 driver to control 4 LEDs in series, but I wouldn't do it.

    If you're really concerned about runtime vs. battery size, then buck type drivers are probably your best choice. These are generally the most efficient, giving you the longest runtimes, but there's risk of them producing bars of light and dark in your video. I would recommend either testing with your camera and various conditions, or researching carefully these (or any other switching regulator) for use with video.

  3. #3

    Default Re: First time build, tube style video light

    DIWdiver, thank you for your post think I have a better idea of the direction I want to go now. Instead of mounting 2 leds per tube I am thinking that I will have 4 individual light heads connected to a single canister. The light head bodies I can put together completely from off the shelf parts saving a lot of work there. Given this, I think that individually driving each LED might be the way to go. Linear 7135s seem like the way to go for simplicity sake, although I am still having a bit of trouble wrapping my head around the voltage they should be supplied. Here is the circuit I am considering:
    LEDS:
    From KAIdomain 4x XM-l T6 LEDS on 14 mm Aluminum Star
    Driver:
    From KAIdomain 4X 8X7135 V2 LED Driver 3040mA 17mm
    Driver Specs are here: http://www.kaidomain.com/product/details.S020073
    Is this the correct type of driver for my application? It says it takes an input voltage of 2.5V to 4.5V, does that mean I need to configure my battery packs such that they are within that voltage when fully charged? Are there 7135 drivers elsewhere that would be better suited?
    Batteries:
    Havenít decided for sure yet what size I am going for. I will probably shoot for 80Wh, the lower end of the spectrum and set up the lights such that I can run either two or four at a time. I wasnít able to source and NiMH AA batteries with specs as high as the 3000mAH but I will have to do some more searching.
    If anyone could help me understand how the wiring of the drivers would work in relation to the voltage of the pack I would appreciate it.
    -Andrew

  4. #4
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    2,464

    Default Re: First time build, tube style video light

    Yes, that driver is of the sort that you want.

    For a linear driver the output voltage is always less than the input. It doesn't have to be much, but always some. For the 7135 the minimum is about 0.15V. This is called the 'dropout voltage'. Say you are running your LED at full power, about 3A. Let's say that at that current the LED drops 3.4V, you lose about 0.2V in your wiring, and the dropout voltage is 0.15V. The sum is 3.75V.

    Lets say when you turn on your light the battery voltage is 4.8V. You get 3A in your LED, 3.4V across it, and 0.2V in wiring. The rest (1.05V) is dropped across the driver. The battery gradually drops to 4V. 3A, 3.4 + 0.2 leaves 0.4V across the driver. It will self-adjust to this point. You should now turn off the light. But you don't know that, and you keep running.

    The battery voltage drops to 3.7V. 3.4 + 0.2 leaves 0.1V across the driver. AnhAnhAnhAnhAnh!!!! Can't happen! The driver won't conduct 3A with only 0.1V across it. What will happen is that the current will be reduced. At some current, the LED voltage, wiring losses, and dropout voltage will equal the battery voltage. This is the current you will see. As the battery voltage continues to decrease, the current will continue to drop, maintaining the equilibrium between LED+wiring+dropout = battery voltage.

    For running individual LEDs with NiMH cells and linear drivers, you absolutely want 4 cells in series for each LED. Fully charged, removed from the charger and put in your light that probably gives right about 6V. That will drop very rapidly to 4.8-5V, then gradually to 4V (maybe 3.8V under heavy load), at which point they are almost completely discharged. You can continue to run them, but they drop pretty fast after that, and it's hard on the batteries.

    Yeah, I might have gotten a bit ahead of the technology figuring 3000 mAH for an AA cell. I have some old Sanyos that are rated 2500, I figured it must have advanced. There are plenty of 3000 rated cells around, but the reviews say they are junk. They seem to top out at 2600 from the respectable brands.

    Yes, you should probably stick to the recommended voltage range. Which sucks because you want to use 4 cells in series, which is 6V fully charged. The spec on the 7135 is 6V, so it's probably the microprocessor that limits the supply voltage. Or someone just put an arbitrary number on the listing, and the board can actually handle 6V. It's cheap enough you could get one and try it. It's a video light, so you aren't risking your safety if it goes bad. Plus, you have quad redundancy. Or you could look for a driver with a range up to 6V.

  5. #5
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    2,464

    Default Re: First time build, tube style video light

    Oops! Double post.

  6. #6
    Enlightened
    Join Date
    Oct 2014
    Location
    Portugal
    Posts
    91

    Default Re: First time build, tube style video light

    Thats intersting!
    But If you want an alternate opinion or other possible way, I would use a single led board and also driver! But this is your choice!

    For the led, the Xml is the right choice for budget, Althrough I might use an Xhp70, so I would keep the 4000lumen but lower the power to 32w (decreasing battery capacity need)
    2pcs Xhp50 would also be a good choice for you, you would have 5000lumen at 38w . For exemple 2 of thoes on copper base http://www.kaidomain.com/product/details.S023976

    As driver I would use this one http://www.ebay.com/itm/LED-driver-L...item1a05b1b863
    or http://www.ebay.com/itm/LED-driver-L...item1a0432d94e
    Because in first place it would be cheaper than 4pcs 5$ driver and the whole set up would get smaller then having 4 drivers
    You can power 4xml serial with it, you just need battery voltage 15v or higher. This driver will also power 1 xhp50

    The batteries, I would use Li-ion! They aren`t much more expensive, but have better life-time, are smaller, and very importante to me, are lighter weight.
    For exemple using 8pcs 18650 ~2800mah (2.8*3.7 = 10.36W-h per battery *8 = ~82.9 Wh

    Instead of 24 AA, you could use 8 18650
    A decent AA ~3000mah will cost you up to 4$, a chinese you might get for 1$ or less...(don`t buy chinese batteries by branded capacity! believe me! )
    A decent manufacturer 3000mah li-ion 18650 will cost you around 5-10$ including PCB ( I recomend if using li-ion and driver without protection for li-ion)

    For exemple 8 of these Samsung 3000mah http://www.ebay.com/itm/4PCS-Protect...item3395c015b1

    Or 10 of these Samsung 2600mah... even cheaper... http://www.ebay.com/itm/10x-Protecte...item3cf9d76bbd


    I wan`t to repeat, this is my opinion or sugestions for your build
    Cheers
    Mark

  7. #7

    Default Re: First time build, tube style video light

    Took me a few days to work with both of your suggestions, I have worked out what the light head enclosure will be now. I am using 3 off the shelf parts from McMaster Carr, (69915K66, 1322K74, 50785K95) + (16 gauge wire w/ .37Ē dia). This does change my original plan of doing tube style but should be much easier to put all of this together and seal it properly.

    Now that I am using this body style I think that doing the two XHP50s might be the way to go. I would get a similar amount of light without needing to manage 4 individual light heads. Especially since this would be my first build having less complexity is probably a good way to go.

    I am now set on NiMH batteries, I saw a good deal on Monday and ordered a set of 12 D size batteries 10000 mAh each. I donít think that I would use all 12, probably a max of 8.

    Now that I will be using two separate light heads I would need to use two separate drivers, correct? Can two drivers be used in parallel, meaning one battery pack for two drivers, or would they each need to have their own battery source?

    Does anyone have any suggestions for a good canister build? Something simple that would be able to hold 8+ D size batteries.

  8. #8
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    2,464

    Default Re: First time build, tube style video light

    Sure, you can run two drivers off one battery, no problem.

    As m.pille.led points out, you can run two LEDs off one driver too. Just because they are in different heads does not necessarily mean they need separate drivers. Separate drivers definitely works, but some drivers can handle several feet of wire in the LED string with no problems.

    There used to be a lot of discussion about canisters on this forum, but not for a year or more. Maybe go back a year and start backward? Or use the search tool.

    I'd rather see you use a cable gland designed to be waterproof, not liquid-tight (NOT the same thing). Check the sticky at the beginning of the dive lighting forum. I think Agro is a brand that folks are very happy with.
    Last edited by DIWdiver; 09-10-2015 at 07:19 PM.

  9. #9
    Enlightened
    Join Date
    Oct 2014
    Location
    Portugal
    Posts
    91

    Default Re: First time build, tube style video light

    Hi,
    About the amount of drivers. You are going to use 8pcs 1,2v batteries, for a total of 9,6v.
    The xhp50 needs 6v, so a single buck or linear driver won`t work! ( unless you know 6A buck driver with 6v output)

    This is one of the points I would have used a couple of 18650, you would get easy over the 14v mark. And 1 driver would be plenty.

    Anyways, what will work for you are two of these, http://www.ebay.com/itm/LED-driver-LDRADJ-3A-30W-3A-DC-6V-28V-Multi-Mode-CREE-XM-L2-XP-L-XHP50-/111767021749
    one for each led, of corse running of the same battery.

    About canisters I don`t know anything.... I myself am looking for an afordable canister to fit around 6-12pcs 18650. Maybe you know some good one DIWdiver?

  10. #10
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    2,464

    Default Re: First time build, tube style video light

    350xfire used to make a nice canister, but I don't know much about the size or what it would fit. Most of the ones I've seen are DIY from standard PVC pipe.

    If you check the Dive Lighting Library sticky, about halfway down is a list of 'DIY Stores' that lists several places that sell canisters, but they are expensive.

  11. #11
    Flashaholic
    Join Date
    Dec 2006
    Location
    New Jersey, USA
    Posts
    406

    Default Re: First time build, tube style video light

    I used Sealcon cable glands in past and they worked fine.
    http://www.productsforautomation.com...ings-s/145.htm
    Just remember that you need to separately order o-ring and locking nut
    Manufacturer info is here.
    They are a NEMA 4x & 6 (IP 68 & 69K), 150 PSIG (10 bar) Liquid Tight Rating

  12. #12
    Enlightened
    Join Date
    Apr 2011
    Location
    Greece
    Posts
    40

    Default Re: First time build, tube style video light

    Hi

    Next month I am planning to built two light heads for video lights.
    The host is a machined 2D mag light with 10mm glass from Hector.
    I will put 6 cree XM-L2 U3 with 14mm PCB. No reflector the leds will be beside the glass
    I calculated the space, 14mm pcb it's prefect for my heatshink.
    I will use two drivers, each one for three leds in series.

    LEDS http://www.dx.com/p/cree-xm-l2-10w-7...2#.VncZgBV95dg
    DRIVERS http://www.ebay.com/itm/111840266214...%3AMEBIDX%3AIT

    I am wondering if this is a good choice. !!!
    I choose XML U3 because I have used the before for other lights but looking around for the leds I came across with newer leds
    cree XP-L HI V2 6500K
    cree XHP 50
    cree XHP 70

    XP-L HI V2 From my research i Found that are little more better ( more lumens) from XM-L2 U3
    cree XHP 50 and cree XHP 70 are much better. I haven't tested before and I am not sure about the drivers I found on Kaidomain site.

    XP-L HI V2 http://www.kaidomain.com/product/details.S024238
    cree XHP 50 http://www.kaidomain.com/product/details.S023988
    cree XHP 70 http://www.kaidomain.com/product/details.S023993

    Drivers
    3 X XHP50
    http://www.kaidomain.com/product/details.S024016
    3 X XHP70 http://www.kaidomain.com/product/details.S024015

    Any suggestion for better drivers ?

    What is the best compilation for max lumens at the same watts

    6 X XM-L2 U3
    6 x XP-L HI V2
    3 X XHP50
    3 X XHP70

    Thanks in Advance
    Dimitris
    Last edited by DimitrisV; 12-21-2015 at 05:28 AM.

  13. #13
    Flashaholic* lucca brassi's Avatar
    Join Date
    Feb 2008
    Location
    Kocevje , Slovenia, Europe
    Posts
    875

    Default Re: First time build, tube style video light

    For video you would use led with 8000K colour temperature ?!

    CONS:

    - it is really strange color violet / blueish ( sometimes I see it on car HID lights )

    -no real illumination

    -overheated leds gets that color


    ***********************

    driver looks very nice build , and very cheap , like it ............. you can't direct fix with some heat conductive tape over whole PCB but to the flat surface but you fix PCB plata against heatsink with FETs between - no problem

    ***********************

    more light is usually better at video so XHP70 http://www.kaidomain.com/product/details.S023993
    Last edited by lucca brassi; 12-21-2015 at 03:33 AM.

  14. #14
    Enlightened
    Join Date
    Apr 2011
    Location
    Greece
    Posts
    40

    Unhappy Re: First time build, tube style video light

    Hi Lucca

    I didn't knew that information about the colour temperature. I thought that more kelvins was better
    something that don't apply in video lights.

    I bought 6 XM-L2 yesterday from DX for 32Ä

    Ι will use triple XHP70 for each head with the drivers from KD

    Thanks for the advice

    Dimitris

  15. #15
    Flashaholic* lucca brassi's Avatar
    Join Date
    Feb 2008
    Location
    Kocevje , Slovenia, Europe
    Posts
    875

    Default Re: First time build, tube style video light

    take something with neutral tint between 4500K-5700K

    http://www.lck-led.com/cree-xlamp-xh...lm-p-1293.html on Cu star (or ceramic if you find )

    http://www.kaidomain.com/product/details.S024139

    you have 6V or 12 V version , you can go with 12V version ( that mean 4 emitters in each ''led'' in series ) and use of LDO ( linear low drop output ) driver if you use for instance LiPo with 4S (14,4V ) DIWdiver make

    some nice LDOs ( benefit is no flickering )http://www.candlepowerforums.com/vb/...w-and-Improved!

  16. #16
    Enlightened
    Join Date
    Apr 2011
    Location
    Greece
    Posts
    40

    Default Re: First time build, tube style video light

    Lucca thanks a lot for the information's and the advises

  17. #17
    Unenlightened
    Join Date
    Oct 2016
    Posts
    1

    Default First time build tube style video light

    i had been wanting to do some decal work on my car but couldnt decide on what just yet. i want to start with some hash marks and decided to plasti dip them cheaper and can easily be removed/changed. does anyone have any tips on doing this and does anyone happen to have some measurements that i could follow as a guideline?

  18. #18
    Flashaholic* DIWdiver's Avatar
    Join Date
    Jan 2010
    Location
    Connecticut, USA
    Posts
    2,464

    Default Re: First time build tube style video light

    Quote Originally Posted by BrianTup View Post
    i had been wanting to do some decal work on my car but couldnt decide on what just yet. i want to start with some hash marks and decided to plasti dip them cheaper and can easily be removed/changed. does anyone have any tips on doing this and does anyone happen to have some measurements that i could follow as a guideline?
    Uh, I think you're in the wrong forum. This is about SCUBA diving lights.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •