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

fivemega

fivemega

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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 ???
 
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DayofReckoning

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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.
 
bykfixer

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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.
 
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DayofReckoning

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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.
 
bykfixer

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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.
 
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mcm308

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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!
 
night.hoodie

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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.

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.
 
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InvisibleFrodo

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So the LEDs remain lit when you twist the tailcap all the way or press the button in all the way to activate the incandescent lamp? I was under the impression that the light ran one or the other.
I never really gave this light much thought until recently very recently. You guys saying the beam is so fantastic and reading that the lamp is regulated and even features a built in soft start? That sounds like a dream light! Throw in a Tad custom adaptor and an onion ring and you have an amazing light. The best of both worlds so to speak...
On the Tads customs site they only recommend bulbs used in A2s with primaries... Will they work with a pair of Li-fe or Li-ion? Someone said the regulator can handle up to 9 volts?
These lights look amazing. The only lights I own from SureFire are all incandescent lights that are now discontinued.
 
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vicv

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Yes they will work with a pair of rechargeable cells. Only problem is it will severely discharge them as it'll take them down to below 2v a cell
 
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InvisibleFrodo

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Most cells with protection circuits will cut out at 2.5 volts, but I never let them get that low anyways. I’m very conscious of lithium batteries. Been using them in RC cars, planes, and helicopters since probably around 2005 if memory serves. Before that it was Ni-MH, and before that, Ni-Cd
 
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True but I don't use protected batteries. plus with RC vehicles and other things you can see when performance starts to drop telling you the batteries are dead. The a2 will not give you any indication the batteries are dead because of the regulated circuit
 
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InvisibleFrodo

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I never noticed a decline in performance toward the end of a run once I started using lithium batteries in RC vehicles. Although most of those cells where Li-Po, and they are flat wafer style cells, not cylindrical like we use in flashlights.
I would use programmable speed controls from Castle Creations almost whenever possible, and they have fully adjustable settings for a low voltage cutoff, and for some reason I never had it actually stop me despite increasing the cutoff voltage.

So in an A2, if I want to use Tads bulbs, should I be sticking to the bulbs rated for 3.7 volts even if I’m using 2 rechargeable cells?
I see they have a 4.8 volt cell they say will be under driven in an A2... Will the 80 lumen 3.7 volt 1.2 amp bulb still put out 80 lumens, or will it be less because of the current control?
 
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InvisibleFrodo

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What about the built in soft start? Is that real? What is the difference between the 4 flats and the round body? I notice the 4 flats say digital plus series and the round bodied ones do not. Is there some performance or design change beyond the flat spots on the body?
 
id30209

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Any A2, flat or round has the same electronic/softstart regulator delivering constant 4V. Using 3.7V cells it won’t mean anything since bulb will still be regulated at 4V. LED’s on the other side will see more than triple current thus causing possible burn out (although i still don’t know for any case).
Using Tad’s 3712 bulb you’ll have more than declared 80lm (or whatever it is, can’t remeber now).
 
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InvisibleFrodo

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Okay, so the regulator delivers 4 volts to the bulb, so the 3712 which is meant to take lithium rechargeable batteries that are 4.2 volts when fully charged should do just fine I would think... That would explain why the 4812 would be under driven. Has anybody here tried that combo? My instincts say that putting 4 volts to a 4.8 volt bulb would result in longer bulb life vs putting 4 volts to a 3.7 volt bulb.
Now I’m seriously tempted to try to acquire one of these. They sound like an absolutely awesome light.
Do the LEDs stay on when the bulb is activated?
 
1pt21

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Any A2, flat or round has the same electronic/softstart regulator delivering constant 4V. Using 3.7V cells it won’t mean anything since bulb will still be regulated at 4V. LED’s on the other side will see more than triple current thus causing possible burn out (although i still don’t know for any case).

I always hear it, and it always scares me a bit. But, has a failure ever been reported?? Ever?? LOL, I'm seriously asking if you (or anyone) know of any failures. I've been doing it for years, never a problem.
 
1pt21

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bykfixer

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I'm always surprised at how few opt for LifePo4 batteries.

Overdriving the LED ring in an aviator may yield a dozen lumens? Can you see that? I can't.

Frodo, you gotta try the A2. On paper it's a bit of a head scratcher, but in use it's an amazing thing to behold. PK once told me a regulated incan was one of his favorite ideas.
 

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