Single XP-G @ 1.5a -drivers?- Mtbr.com
Results 1 to 26 of 26
  1. #1
    mtbr member
    Reputation:
    Join Date
    Oct 2009
    Posts
    14

    Single XP-G @ 1.5a -drivers?

    Greetings!

    I am in the early layout stages of trying to put together a single XP-G but want to run it at or near its max rating and am having difficulty finding the right way to regulate it.

    I wish to keep things as simple (and *cheap*) as possible.
    note: I currently have 18650 packs @ 11.1v & 14.8v but am willing to entertain other battery options if that will simplify things.

    My desired goal is to have multiple brightness settings (5 would be nice: roughly 100ma;350ma;700ma;1a; 1.4a -somewhere in those ranges). I suppose I could tolerate another pot but caving is really brutal on them so I'd prefer a waterproof clicky switch option ideally.
    (I built a dual xp-g light couple yrs ago w/ 1a buckpuck but want to simplify -thought I'd need alot more light but feel that 400-450lm will do nicely, thus needing to drive a single at higher amps)

    So I'm looking for suggestions on how to regulate this thing -can't find one that will go to 1.5a

    Could I use two 750ma bucks in parallel?(assuming I stay with the 18650 packs)

    Are there better, more energy efficient ways to accomplish my goals?

    All my plans are open to revisions so, Any suggestions/opinions welcomed! Thanks!!

  2. #2
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    291
    I designed the b2flex to specifically provide a 1.5A output capability and it can be operated via a momentary action switch (which could be a reed that is magnetically activated externally). Anyhow, it has a lot of features, but I wouldn't classify it as 'cheap'...

    A lot of folk have used the older bflex (1A max) in bikes and caving, the b2flex has all the same features but adds the ability to output up to 1.5A. It can monitor and warn of med/low battery voltage via the main LED or a separate status LED.

    Anyhow, hope this doesn't sound like an "advert" - but I'd suggest you check out the b2flex specs and see if it is a good fit for what you want of your driver.

    cheers,
    george.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Oct 2009
    Posts
    14
    Hi George,

    Thanks for the info -it looks like a sweet driver. Couldn't find any pricing on it but if it's like what's listed on similar units at the Cutter site($45+)... 2/3 the cost of my last dual xp-g for just the driver might be out of my league, sadly

    I guess I'm not trying to be *super* cheap but am trying to keep the entire build to under $65 if possible.

    Greatly appreciate the info!

  4. #4
    mtbr member
    Reputation:
    Join Date
    Nov 2010
    Posts
    2
    Regulated circuit board designed for Cree XP-G and XR-E emitters
    * 3 modes: Low>Med>High
    * Voltage input: 2.8V - 6V
    * The memory feature will memorize the last mode
    * Output current: 60mA on low, 440mA on medium and 1.4A on high
    * Buck circuit board
    * Linear regulators for high efficiency
    * 17mm base board diameter
    * Lead wires already soldered on board
    * Reverse-polarity protection prevents wrongly installed batteries from damaging the circuit


    If you want cheap and reliable, I would use this driver from shining beam

  5. #5
    mtbr member
    Reputation: gticlay's Avatar
    Join Date
    Dec 2007
    Posts
    6,655
    Quote Originally Posted by holdthat1
    Regulated circuit board designed for Cree XP-G and XR-E emitters
    * 3 modes: Low>Med>High
    * Voltage input: 2.8V - 6V
    * The memory feature will memorize the last mode
    * Output current: 60mA on low, 440mA on medium and 1.4A on high
    * Buck circuit board
    * Linear regulators for high efficiency
    * 17mm base board diameter
    * Lead wires already soldered on board
    * Reverse-polarity protection prevents wrongly installed batteries from damaging the circuit


    If you want cheap and reliable, I would use this driver from shining beam

    What kind of run time would an R5 XPG have on high with 2 18650 cells ?
    "It looks flexy"

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    291
    There is some markup going through Cutter, I sell direct for less (see my website), esp if you are not in oz.

    The shining beam unit is a linear regulator NOT a buck. It burns excess voltage as heat and I would hardly call that 'efficient'. It would only be applicable where the battery voltage is near the LED Vf, i.e one LED and one li-ion cell.

    cheers,
    george.

  7. #7
    mtbr member
    Reputation: gticlay's Avatar
    Join Date
    Dec 2007
    Posts
    6,655
    Quote Originally Posted by georges80
    There is some markup going through Cutter, I sell direct for less (see my website), esp if you are not in oz.

    The shining beam unit is a linear regulator NOT a buck. It burns excess voltage as heat and I would hardly call that 'efficient'. It would only be applicable where the battery voltage is near the LED Vf, i.e one LED and one li-ion cell.

    cheers,
    george.
    taskled.com?
    "It looks flexy"

  8. #8
    mtbr member
    Reputation:
    Join Date
    May 2005
    Posts
    3,829
    For a caving application, I would not scrimp on the driver. IMO you can not do better than the Taskled drivers.

  9. #9
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    I wondering if you'd be able to keep a single XP-G cool at 1.5A though, especially without the airflow you'd have with a bike light, and if the higher power draw and decrease in efficiency would be worth the extra lumens.

    I'd second the b2flex, fantastic bit of kit, but not what I'd call "cheap". I think the failsafes, such as overtemp protection and overdischarge warning, are worth the extra and would definitely be so in a caving light (shudders at thought of being stuck in a cave without light).

    A cheaper option would be to get 2 750mA drivers from Deal Extreme and wire them in series as EL34 on here has done (search for him or his website Hoffman Amps), although he used 2 1.4A drivers to get 2.8A IIRC. I don't personally like the sound of that, but that would run you to $10 or so compared to $38 for the b2flex.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Oct 2009
    Posts
    14
    The heat issue is not of great concern as the times that I'd drive it that hard would be infrequent and short term -still need the power on hand tho. Caves are a cool environment and an old 486 heatsink was more than enough for my dual XP-G light.

    I will be running this at really low voltage 60% time and full bore maybe 5% In fact the lowest setting of the [email protected](?) would probably be overkill @ 137lm. I think this was the reason I went with a pot last time. I usually can get away with 1/3 that power (lots of tight crawlways in my neck of the woods).

    Tho looking at the price on Taskled site is certainly more affordable than others but would still prefer a less expensive option.

    I do have a question about the B2 re: UIP vs UIF vs etc... Guess I'm not hip on the lingo of what these are. I like the idea of an 8 brightness setting tho.

    One of the problems with the other drivers seems to be the max Vin. My current packs are in series (tho I suppose I could rewire them for parallel) and are 11.1 v and above. Most other drivers seem to have a limit of 6-8v and lots of additional Vf

    Would I be able to direct drive this LED? If I made a 3.7v, high Mah pack, would that work? The Vf of the [email protected] is just under that at 3.5v. This would leave no brightness adjustment but maybe a pot thrown in the mix? Seems inefficient tho -wouldn't that just dump tons of heat as lost energy?

    Ah, my age addled brain... I use to understand this stuff so much better when I was young.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    291
    UIF is the fixed lighting UI (click on/off, press to dim/brighten)
    UIP is the portable lighting UI (click on/off, press on to adjust, press from on to go to high)
    UIB is the bike UI (click to turn on, press to turn off).

    I'd think for caving the UIB would make sense, easy to turn on (click), harder to turn off (long press time). I certainly wouldn't want to be able to easily turn off a caving light once in a dark cave

    Anyhow, most DX drivers are just using a bunch of paralleled linear regulators to dump excess voltage into heat - hence their 6V or 8V limits on input - they are trying to minimize how much heat they have to dump.

    If you have multicell battery packs and a single LED then you definitely need a buck driver to make efficient use of that 'extra' voltage.

    For a single XP-G I would NOT recommend to direct drive from a li-ion - you will be pushing way too much current when the battery is fresh off the charger. Using a Pot to dim would be no better than a linear regulator driver - excess goes in heat and you still have no regulation of maximum current. Factor in that the LED Vf will drop as it heats up and you have the recipe for a stressed LED and reduced life/lumen output etc.

    cheers,
    george.

  12. #12
    mtbr member
    Reputation:
    Join Date
    Nov 2010
    Posts
    8

  13. #13
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    291
    Again, these are LINEAR REGULATOR units - that's why they are cheap. They are only applicable when the battery voltage is close to the total LED Vf, otherwise they will overheat since any excess voltage will be 'converted' to heat....

    Folk need to understand the difference between a buck (DCC energy conversion) versus a Linear Regulator which just shunts excess voltage x current into heat. The Linear Regulator is great when you only have to drop a volt or so.

    Drop a volt at 1.5A output and that's 1.5A x 1V = 1.5W in heat that is lost in the driver. Drop 2V at 1.5A and you have 1.5A x 2V = 3W in heat that is lost in the driver etc etc...

    cheers,
    george.

  14. #14
    mtbr member
    Reputation:
    Join Date
    Feb 2010
    Posts
    876
    You may check out my simple single XP-G light driver: http://forums.mtbr.com/showthread.php?t=667644

    It uses the linear regulator from DealExtreme, but since I'm using single cell, the voltage difference between LED and battery is sufficiently low and the average efficieny of the driver over the battery discharge is around 86%. Not great, but for me it was good compromise. I also added higher-voltage (3.08V) low-voltage cutoff and pushbutton control.

    BTW, if you modify the circuit, so that you can turn the four regulator chips on and off independly, then it is possible to achieve four different power levels: 350ma (1 regulator working), 700ma (two regulators working), 1050ma (three regulators working) and 1400ma (all four working). I do not have good ideas for this circuit though. Perhaps some rotary switch with multiple poles?

    Arne

  15. #15
    A waste of time it is is
    Reputation: emu26's Avatar
    Join Date
    Jun 2008
    Posts
    3,456
    +1 for the Taskled drivers.

    The relatively small additional outlay will be well worth the added functionality of your light.

    Don't know about you but I reckon I'd be pretty pi$$ed if saving myself $20 now meant I was stuck down a small, dark hole somewhere in a years time

  16. #16
    mtbr member
    Reputation:
    Join Date
    Oct 2009
    Posts
    14
    Thanks everyone for their great input!!

    will be going the flex-y route. I am also considering isolating the driver&control switch from the light and PS to allow for more cost effective use of multiple light setups/upgrades.

    Wiring distances from PS to LEDs would be about 18-20"
    Would this cause any issues for current/V control or meaningful efficiency losses?

  17. #17
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    if it is at all possible, I'd recommend keeping the driver with the lighthead. Not because of any voltage losses but because you'll have the benefit of temperature sensing, plus the driver will be heatsinked to the light, not to the battery.

    The downside is that it's a slightly awkward size at 25mm.

  18. #18
    mtbr member
    Reputation:
    Join Date
    Jun 2008
    Posts
    27
    George I like your drivers but I also think that the size of 25 mm is to large. Most optics and reflectors are 16-22 mm which argues for smaller drivers as well.

    Do you see that as possibility?

  19. #19
    mtbr member
    Reputation:
    Join Date
    Sep 2007
    Posts
    759
    So far the only decent alternative to the taskled drivers that i have tried and had good results with are the stuff from the sandwich shoppe.
    http://theledguy.chainreactionweb.co...cPath=48_49_61
    I have used the shark boost converter and it works as advertised. With out the UI boards the sandwich shoppe boards are a little cheaper, and some what smaller than taskled. They also lack all the great features and are not quite as efficient. The taskled stuff puts features and performance before size.

    Here is a great thread on cheap stuff that actually works unless you get a dud board which I have on more than one occasion. Also be aware that the version that ships can change quickly with out warning with the cheap stuff from china.

    http://forums.mtbr.com/showthread.ph...ghly+Efficient

    http://forums.mtbr.com/showthread.php?t=492861

    If you order your LED and optics from cutter the RECOM stuff have excellent specs. the recom stuff is small and more efficient than the buck puck stuff.

  20. #20
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    291
    Quote Originally Posted by thides74
    George I like your drivers but I also think that the size of 25 mm is to large. Most optics and reflectors are 16-22 mm which argues for smaller drivers as well.

    Do you see that as possibility?
    The issue is that size is necessary to provide space for thermal dissipation and/or for allowing an area of the board for attaching the driver to a heatsink.

    Since I have to design for a wide range of input voltage and output voltage and output current I have to be conservative with component selection (e.g. larger inductor than would be needed for say a single LED design at lower current).

    So, I agree that for a single LED with tiny optic 1" for the driver is a problem, but then for a triple LED and triple optic it would be just fine.

    Can't please everyone all the time

    cheers,
    george.

  21. #21
    Do It Yourself
    Reputation: Homebrew's Avatar
    Join Date
    Jan 2004
    Posts
    5,720
    Quote Originally Posted by georges80
    So, I agree that for a single LED with tiny optic 1" for the driver is a problem, but then for a triple LED and triple optic it would be just fine.
    Have you considered a 17mm "MicroFlex" for smaller applications? This would be perfect for CPF market as well. You might consider something for a single XM-L as well. That's seems like the hot ticket coming for 2011.
    Long Live Long Rides

  22. #22
    mtbr member
    Reputation:
    Join Date
    Apr 2010
    Posts
    489
    Quote Originally Posted by Homebrew
    Have you considered a 17mm "MicroFlex" for smaller applications? This would be perfect for CPF market as well. You might consider something for a single XM-L as well. That's seems like the hot ticket coming for 2011.
    ++1

  23. #23
    A waste of time it is is
    Reputation: emu26's Avatar
    Join Date
    Jun 2008
    Posts
    3,456
    Does a maxflex not fit the bill with a smaller battery?

  24. #24
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    291
    Quote Originally Posted by Homebrew
    Have you considered a 17mm "MicroFlex" for smaller applications? This would be perfect for CPF market as well. You might consider something for a single XM-L as well. That's seems like the hot ticket coming for 2011.
    Well, for the XM-L most folk will want to run 3A and that's a heap of power to push into a driver that small AND have room for the 'flex' part of the electronics. You also need to factor you have >10W, so even though you may have a tiny LED and tiny optic you still need to have a case/surface area to dissipate >10W of heat.

    Besides, most of you crazies won't be happy with a single XM-L anyway

    I recently added 3A and 6A (for parallel xm-l) tables to the h6flex driver. Once you get into the 3A or greater range it becomes necessary to go to external FETs and that takes more space...

    The other option is to move the driver out of the LED housing and put it in the battery pack, especially for helmet light and tethered battery pack.

    The CPF market (flashlights) is not something that I've focused on - then I'd be in the retrofit market and competing with $3.99 Walmart lights or the latest DX light.

    I've tried to supply drivers that hit sweet spots in terms of features and performance and sometimes that means the driver needs to be larger to be able to handle a range of input/output voltage/current requirements. It's the simple case of trying to minimize my inventory of different drivers so I don't get stuck with 100's of boards that no one wants to purchase.

    I could go on and on about the numerous choices and tradeoffs that go on before I commit to taking a driver to production and it's a little more complicated than throwing darts at a dart board

    cheers,
    george.

  25. #25
    mtbr member
    Reputation: troutie-mtb's Avatar
    Join Date
    Sep 2007
    Posts
    3,062
    Quote Originally Posted by georges80
    Besides, most of you crazies won't be happy with a single XM-L anyway
    cheers,
    george.

    Are we so transparent George

  26. #26
    mtbr member
    Reputation: Lumbee1's Avatar
    Join Date
    Dec 2004
    Posts
    1,908
    I have two FatMan (FatMen?) from George and I LOVE them. Analog log pot for easy adjusting of the light output, solid consistent light output for hours on end. I have tried some of the dealextreme drivers and needless to say, I was disappointed. Some got incredibly hot (actually they all got hot compared to the Fatman) but every one of them drained the batteries dry in a very short time.

    I am considering another light build with the XM-L and instead of bothering with cheaper alternatives, I will go with a Taskled driver and build around it. I know that I will get consist, reliable performance and can use the driver for future light builds.

Members who have read this thread: 0

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.