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Thread: Surefire A2 Aviator bi-pin adaptors/Tad's customs

  1. #181
    Flashaholic* fivemega's Avatar
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    Default Re: Surefire A2 Aviator bi-pin adaptors/Tad's customs

    Quote Originally Posted by DayofReckoning View Post
    When the A2 drop's out of regulation, the lamp is SEVERELY underdriven. I don't know how many lumens the lamp is putting out at this point, but it's very, very dim.
    I didn't know lamp can be underdriven in A2
    Are you talking about incand $urefire A2 ???

  2. #182
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    Default Re: Surefire A2 Aviator bi-pin adaptors/Tad's customs

    Quote Originally Posted by fivemega View Post
    I didn't know lamp can be underdriven in A2
    Are you talking about incand $urefire A2 ???
    Yes. When the batteries can not long provide full current to the regulator for full brightness, the incandescent bulb will drop into a very low output mode where it is very underdriven. This is common knowledge.

  3. #183

    Default Re: Surefire A2 Aviator bi-pin adaptors/Tad's customs

    I did not know that DoR. I'm new to the A2.

    So when it goes into the 'dim' mode, which btw may be part of a regulation to show "hey, your batteries are low"....does the ability to keep it on for a while exist or does it dim then shut off?

    I use the LED of my A2 99% of the time since ordinarily I have a brighter light handy. So a pair of primaries may last years in my case. But I just wondered how long you have to 'find' new fuel in the event the brighter output is needed.

    I say the dim may be a part of the regulation knowing that PK makes his newer lights so that they don't fall out of regulation. Instead they switch to a lower output kinda like shifting a car into low gear. And he played a big part in the A2 design way back when.
    John 3:16

  4. #184
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    Default Re: Surefire A2 Aviator bi-pin adaptors/Tad's customs

    When it drops into the dim incandescent mode, it will not run very long at all, maybe a few minutes I'm guessing? And will progressively grow dimmer, and dimmer quickly. However, the beautiful thing about the A2 is the LED's at this point will run for a very long time.

    Now that I think of it, for some weird reason, the LED's themselves actually have 2 levels of brightness whenever one's cells are depleted enough that the incan lamp won't fire up. When one turns on the LED's at this point, if you fully press the tailcap switch, or full tightnen the tailcap, the LED's will gain a little brightness. I don't know why it does this, but both my A2's do this, and I've seen other comment their does it as well.

  5. #185

    Default Re: Surefire A2 Aviator bi-pin adaptors/Tad's customs

    The dimmer and dimmer sounds just like what PKDL PR-1 light does when a primary is running out of fuel. It will flash a few times first, then down shift to a lower setting (medium) then a few minutes later the low that provides a minute or so of steady output. Then it begins to quickly fade. From the flash mode you have about 5 minutes to find new fuel.

    I suppose the A2 LED can run full output on a lot less voltage than it's incan counterpart. Again using a car analogy, perhaps it's like a big block engine that has ability to start out with a 3 cylinder engine. ie the LED to start with ability to add the light bulb.

    So I speculate the light is designed to allow you to stomp the accelerator while out of regulation. If I understand correctly the bulb is what is regulated. Not the LED's but I may be wrong there.

    Either way, yeah I can see where a low fuel situation will allow the light bulb to be greatly under driven.
    John 3:16

  6. #186

    Default Re: Surefire A2 Aviator bi-pin adaptors/Tad's customs

    I am an another that when I die, my A2 is going under with me. I used to have a bunch, all different colors, although never had the elusive "BK".. When my main drops out, I always switch the batts with fresh. Ill never know when I need that main to fire. I keep the depleted batteries to use in emergency situations like when my house loses power and all I need are the LEDs for a bit of light. They work exceptionally well for that. And Ill also use them up in other single cell LED's I have.

    But my A2 always gets fresh cells!

  7. #187

    Default Re: Surefire A2 Aviator bi-pin adaptors/Tad's customs

    Quote Originally Posted by DayofReckoning View Post
    Now that I think of it, for some weird reason, the LED's themselves actually have 2 levels of brightness whenever one's cells are depleted enough that the incan lamp won't fire up. When one turns on the LED's at this point, if you fully press the tailcap switch, or full tightnen the tailcap, the LED's will gain a little brightness. I don't know why it does this, but both my A2's do this, and I've seen other comment their does it as well.

    This is by design and due to the tailcap 10ohm resistor. The lamp is regulated, but the LED ring is direct drive when the lamp is lit, though it stays activated in both modes. In the mode with the lamp, (noticeable when the lamp can no longer be lit by the cells) the LEDs will appear brighter because the resistor is no longer in the circuit, LED ring is directly driven.

    Quote Originally Posted by js View Post
    When you activate the switch to the first position, there is a 10 ohm resistor from the battery stack negative to the LED ring negative, and a direct connection to the battery stack positive. Close the switch all the way, and the 10 ohm resistor is replaced by a short circuit, or in other words, a direct drive to the LED with no extra resistance. You may be able to prove this to yourself, by removing the lamp from the head, reinstalling the head without the lamp, and activating the switch. In some A2's, the LED ring contacts will mate with the middle ring and body of the light even without the lamp in place, and you can see that taking the 10 ohm resistor out of the circuit by depressing the switch all the way makes the LED's brighter than they are with just the first position activation.

    But is the dead lamp eating any power (I was always told a burned-out lightbulb uses more electricity), or does the regulator bypass the lamp once it can no longer be powered? This is a detail we'll want to know when having a reason to efficiently use what remains in nearly depleated cells.

    I expect the answer is "no," because the lamp isn't "burned out," instead there is merely not enough voltage supplied to the regulator to light the lamp.
    Last edited by night.hoodie; 07-30-2018 at 02:36 PM.

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