Rate my build please- Mtbr.com
Results 1 to 8 of 8
  1. #1
    mtbr member
    Reputation: deesta's Avatar
    Join Date
    Sep 2008
    Posts
    1,017

    Idea! Rate my build please

    In the process of making 2 new lights as my current ones are a few years old now.
    This is what I'm thinking, your thoughts would be good. Calculations of output would be great too
    All parts will be sourced form Cutters and TaskLED...

    Bars:
    7-up XP-L V62A Cutter Electronics, Supplier of lowest cost leds on the internet
    Anna 7-up optic Cutter Electronics, Supplier of lowest cost leds on the internet
    HBFlex @ 3a
    15v 5.2aH battery
    Lumens approx 7600 before losses?

    Helmet:
    3 x XP-L High Intensity V21A Cutter Electronics, Supplier of lowest cost leds on the internet
    Regina optics Cutter Electronics, Supplier of lowest cost leds on the internet
    HBFlex @ 3a
    7.5v2.6aH battery
    Lumens approx 3200 before losses?

    Does that look like a decent set-up?
    Cheers
    Steve

  2. #2
    Drinkin' the 29er KoolAid
    Reputation: kwarwick's Avatar
    Join Date
    Jun 2004
    Posts
    1,509
    Both those lights look like excellent choices in components.

    The key of course will be housings with the appropriate balance of reasonable weight and enough surface area to dissipate the massive amounts of heat that would be generated if you run those on high for any length of time.

    For the bar light you may also want to consider a 3 x XHP-50 rather than the 7 up XP-L board...or if you really want to go crazy how about a 3 x MT-G2 light?

  3. #3
    RAKC
    Reputation: tigris99's Avatar
    Join Date
    Aug 2012
    Posts
    7,487
    Quality of parts choices is there, but your going to run into ALOT of problems with heat and battery life. Your trying to lower alot with as little battery power as possible, not going to end well. Not for the batteries anyway. I dont think youll end up happy at all when you run into the heat problems and such that are going to happen with the bar light, or the EXTREMELY short run time of the helmet light. Listen to Kwarwick, probably much better ways to acoomplish what your trying to do with alot less work and lumens that is going to be a waste as youll never see your helmet light in front of you due to the bar light drowning everything out. Better battery pack for the helmet set up (imo at least 2 2600mah 18650 cells) and IMO rethink the bar light matter. H6flex 6.6A with emitters in parallel and a 2s4p pack (same number of cells as you listed just configured the opposite) and youll be close to 3500 lumens with much less heat and battery issues to worry about. And still more light than youll actually need, be able to see what your helmet light is doing more than just when you look to the sides instead of the trail.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Sep 2007
    Posts
    758
    The 7up xp-l bar light seems like a good build. How ever I would not go with a boost driver configuration. If things get really hot they go out a lot sooner than a buck driver.

    I also a distaste in general of parallel wiring.

    I say just go b-flex with a 5 cell battery. The buck is more efficient and for does not make much heat of its own. After all any heat is makes robs the LEDs of lower temperatures and more lumens.

    What is the forward voltage of the xp-l. 2.95V? x 7 =20.65V

    Cut off input voltage from 5S lithium battery at 3.2V x7 = 22.4V
    thats 1.75 volts over the forward voltage
    b3 flex only needs 1.1v above forward voltage
    forward voltage at 3A is more/
    3.25 Vf at 3A x 7 is 22.5V so set cut out voltage at 22.6 or so and it stays in regulation.

    3A which happens to be both LED max current and max current out for b3flex.

    B3flex and a 5 series battery may be a very close to perfect match up. With input voltage close to output voltage the b3flex wont need to do very much.

    That was fun.

    70 watts sounds huge but I have seen so much CNC bling from you that its sort of a non issue.

    It will will out do my cree mk-r with old b-flex and 4 cell battery but I think i still have input and output voltage closer.

  5. #5
    Drinkin' the 29er KoolAid
    Reputation: kwarwick's Avatar
    Join Date
    Jun 2004
    Posts
    1,509
    Quote Originally Posted by bikerjay View Post
    Cut off input voltage from 5S lithium battery at 3.2V x7 = 22.4V
    thats 1.75 volts over the forward voltage
    b3 flex only needs 1.1v above forward voltage
    forward voltage at 3A is more/
    3.25 Vf at 3A x 7 is 22.5V so set cut out voltage at 22.6 or so and it stays in regulation.
    The one problem I see with this calculation is it doesn't take into consideration losses in the power supply wires as well as the inevitable voltage sag the battery will have under load. In my experience this can easily account for a volt or more depending on length of wires and quality of battery. So the problem I foresee is such a configuration would work fine with fully charged batteries, but would drop out of regulation too early.

    While I agree with the sentiment that a buck is preferable to a boost driver in most situations, a 7 xpl light might not be one of them because of voltage limitations. Its too bad the B3flex can't go higher than 5 lithium cells in series because 6 would easily solve this concern.

    The Hbflex would probably be the way to go... running it from 4 lithium cells would be best as then you're not asking it to boost too much and the heat it would generate should be manageable.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    1,842
    +1 but we also didn't take into account changes because of the heating where Vf is also changing.
    "As LEDs heat up, the forward voltage drops (Figure 2) and the current passing through the LED increases. The increased current generates additional heating of the junction. If nothing limits the current, the junction will fail due to the heat. This phenomenon is referred to as thermal runaway. "
    Source: Driving LED lamps ? some simple design guidelines - LEDs

    OK now Cree is publishing their Vf/current graphs at 85 degC at junction point, so more realistic and we don't need to care for that aspect anymore.

  7. #7
    Killer b.
    Reputation: The Understater's Avatar
    Join Date
    May 2007
    Posts
    1,522
    I'm running the new XP-L Hi intensity leds in tiny housings with the Carclo triple optics. 2 boards wired series run off a 5 cell 18650 pack.(Helmet light). I have been disappointed with the output. The forward voltage of the 6 leds run in series leaves almost no overhead with a 5s pack, so after an hour or so I can no longer get to full output with a b3Flex.
    And the leds themselves do not focus at all well with the tiny optics so the throw that I was looking for just isn't there. They might throw brilliantly through the Reginas but those have a hell of a cutoff at the edge, which I find annoying in any light.

    I am going to change them out. The current plan is to do 2 XP-G2 and 1 XP-E2 on each board. Or maybe even one each XP-G2, XP-E2, and de-domed XP-E2 for extra throw.

    Regarding heat management, I have found that running the XP-Ls at 3amps on the Noctigon triples is a non-issue. My housings barely get warm while riding.

    My build:
    HK ? View topic - Revolver Mk IV.
    Last edited by The Understater; 08-28-2015 at 04:54 PM.
    Posting on the basis that ignorance shared is ignorance doubled.

  8. #8
    Killer b.
    Reputation: The Understater's Avatar
    Join Date
    May 2007
    Posts
    1,522
    ....Also, I'm pretty sure the XP-Ls wont' fit under that 7up optic. The domes are too big. The XP-L Hi intensity ones will, but I think you will be disappointed by the overall output due to poor focus. I reckon you will be better off running XP-G2s at 1.5 amps. This will simplify your power requirements too.
    Posting on the basis that ignorance shared is ignorance doubled.

Similar Threads

  1. RATE MY FIRST BUILD FROM SCRATCH!! pics.......
    By PooPooPeePee in forum General Discussion
    Replies: 48
    Last Post: 11-20-2015, 06:51 PM
  2. Rate Your Ride!
    By Game_Throne in forum General Discussion
    Replies: 22
    Last Post: 07-30-2015, 02:20 PM
  3. Replies: 10
    Last Post: 07-10-2014, 02:34 PM
  4. Rate my first wheel build
    By asval in forum Wheels and Tires
    Replies: 14
    Last Post: 11-20-2012, 09:50 AM
  5. Rate Bike Build
    By nikojan in forum General Discussion
    Replies: 0
    Last Post: 07-05-2011, 11:22 AM

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.