CR123a Battery Behavior

[rickb]

Can anyone tall me how the special batteries used in Tactical Flashlights perform as they approach the end of their lives?

I am particularly interested in the CR123a batteries.

Do they die all at once or go quickly at the end?

Or do they "warn you" of their pending demise by going noticeably dimmer for a number of hours first?

If The latter is the case, would you notice the lower output when using the flashlight on its lowere brightness levels, or just on it blinding bright full beam?

[The Cleaner]

I've had some that just look a little less bright and then it's a quick death.It's a trade-off for their super brightness and lightweight.I'm sure anyone using these for "tactical" use would carry spares too.If using xenon bulbs,they don't last that long either.

[Gambit McCrae]

It is not a direct relation to your question BUT if you are looking to transfer to CR123a batteries I can provide this:

I tried and tried using them and with the amount of night hiking I was doing at the time I was going thru a lot of batteries a trip and they were not always reliable. I have resorted back to good ol AAA batteries and be done with it.

[Dochartaigh]

Can anyone tall me how the special batteries used in Tactical Flashlights perform as they approach the end of their lives?

I am particularly interested in the CR123a batteries.

As with any flashlight, this is dependent on the flashlight itself and NOT the batteries. Some flashlights regulate the power going to the bulb/LED so it's the same brightness for the entire runtime, and others run direct-drive which means they run directly off the battery with no circuitry so they will dim as the voltage coming from the battery starts to drop.

High quality tactical flashlights (think SureFire weapon lights) are usually direct-drive so they're as bright as they can possible be - and give plenty of warning when they're dimming and it's time to change the batteries.




I tried and tried using them and with the amount of night hiking I was doing at the time I was going thru a lot of batteries a trip and they were not always reliable.
To the reliability, you had to be using inexpensive and/or knock-off CR123's. Tactical lights like Surefire, running Surefire brand CR123's are the most reliable flashlights and batteries out there. There is literally nothing better since peoples lives (cops, military, etc.) depend on them in life and death situations. Chinese knock-off CR123 batteries....not so much.

I do completely agree on runtime though. Tactical lights are meant to be extremely bright, and used sparingly (light discipline with the bad guy out there looking for you and all), and don't have a long runtime at all (usually 1-2 hours, maybe 3 max for a 2x CR123 light).

[Miner]

I have a fenix flashlight that takes 1xCR123. At the lowest setting I can get about 100 hours, the brightest setting 2-3 hours. I can do most things including night hiking on a well defined Trail on the lowest setting. Holding a light down low gives me a better visability of the trail and all the roots, holes, and rocks at a lower setting than what I need with a headlamp.

As for you question, my lights are regulated so they die fast when the battery gets low. And Cr123 batteries aren't cheap. So most of the time I take my 1xAA version of the same light that is slightly heavier, shorter run time, and not as bright on the highest setting and use a rechargeable battery so I can recharge it between trips.

[Slo-go'en]

CR123A, being a lithium battery has a fairly flat discharge curve until it gets near the end of it's life, then it drops off quickly. Once you see the light start to noticeably dim, you don't have much time left, but you'll probably get some light for some time. Exactly how the light behaves depends on the design of the flashlight.

[rickb]

As with any flashlight, this is dependent on the flashlight itself and NOT the batteries.

This the one I have.

http://www.rei.com/product/881922/fenix-pd35-flashlight

My dilemma is that I really don't have a clue how many hours it's been used (most were at the lowest setting but at home I have used it a bunch on full blast. I wish there was a good way to know how much juice aI have left.

[Dochartaigh]

In the description of that light it says "Regulated output maintains consistent light output over the lifetime of the batteries".

That means it's going to maintain that same regular brightness you're used to until the batteries are pretty much completely dead. Some lights will then only let you turn the light onto the very lowest setting (with just enough light to barely see the ground in front of you - think of it as a safety feature of sorts to let you navigate someplace not-too-far-away safely before it totally dies).

[Slo-go'en]

Regulated, constant light means your probably not going to get much warning it's about to fail. The only safe thing to do is keep a spare battery handy. And don't use it much on high, you only get a bit over an hour with that setting.

[Googan]

I've used 123's in a Malkoff MD2 HILO Clicky. They give you no warning when they go out. I will admit that on low beam they last a decent amount of time, but not on high. There is also reasonable light on low, but it definitely doesnt throw like it does on high

[Starchild]

....
High quality tactical flashlights (think SureFire weapon lights) are usually direct-drive so they're as bright as they can possible be - and give plenty of warning when they're dimming and it's time to change the batteries.
....

They may be direct drive (I really have no idea) but what you say here does not make sense.

Using a voltage regulator would give the ability to boost the voltage to full, even boost it above the starting battery voltage, and keep it there as long as the battery could supply the current. So the result is the potential for full new battery brightness or more till the battery is nearly dead (at which case it can drop to direct drive for the rest of the battery life). It would also result in total less run time per battery.

Direct drive would only give full output when the battery is new and gradually fade, this would extend run time. So in this I agree direct drive would give more warning about the battery condition.

The voltage regulator also would introduce some inefficiencies and losses however that might be really small as to be negligible.

[Dochartaigh]

Starchild, for decades most Surefire lights are direct drive because they're weapon lights meant to be mounted on firearms. Direct drive is literally a battery tube with a spring, and a purely mechanical on/off switch. They have no circuits, no chips, no wires to break as the weapon recoils as it's shot for tens of thousands of rounds. They do this because it's the most reliable system when lives are on the line. I'm sure their newer lights are/will-be regulated as they perfect different systems, but none of the tens I've owned were.

If you're talking about the light being able to go brighter if it is regulated (vs. dimmer on direct drive), and I'm no electrical engineer here at all, but I'm pretty sure running direct drive gives you the highest possible amps to the bulb. Regulated could up the voltage but I'm pretty sure you can't eek more amps out of the battery with circuitry without a delay. So once the voltage requirement of the light is met (which they're usually designed for 1 or 2 cells), it's all about the amps to get the light as bright as possible which direct drive certainly does.

[rafe]

With active circuitry, you could drive as much current through the bulb or LED as you wanted to -- within the limits of the battery's C-rating and amp-hour rating.

[rafe]

... and the current limits of the bulb or LED, obviously.

[Starchild]

...

If you're talking about the light being able to go brighter if it is regulated (vs. dimmer on direct drive), and I'm no electrical engineer here at all, but I'm pretty sure running direct drive gives you the highest possible amps to the bulb. Regulated could up the voltage but I'm pretty sure you can't eek more amps out of the battery with circuitry without a delay. So once the voltage requirement of the light is met (which they're usually designed for 1 or 2 cells), it's all about the amps to get the light as bright as possible which direct drive certainly does.

This was the part I was referring to (it does make sense for the practical durability purposes to go direct drive, most likely that is the reason).

Yes voltage regulators can get higher voltages AND higher current out of the battery delivered to the bulb (the trade off is total run time before the battery goes dead). That's what they do and they would have to do both (higher current and higher voltage) to get higher light output. They way they do this is trade volt for amps and also by drawing more total power from the batteries then direct drive is capable of (so drawing more power draws more total amps to use to get to a higher voltage). As long as the battery can supply the amps the voltage regulator can supply the constant high voltage and proper amps for the circuit. At the end of battery life however the voltage regulator will no longer be able to get enough current to sustain the power draw and need to drop out of the circuit or shut down.

Direct drive can only get the voltage of the battery 'as is'. That voltage supplied to the LED will draw a certain current to the bulb. You can not push any more current though even if you have it because the voltage is what it is and is the only driving force for that current.


Voltage regulators are pretty much instant on, no time delay effects should be noticed.

[Slo-go'en]

I am an EE. White LED's require about 3.2 volts to turn on and produce any light. The amount of light produced is a product of the amount of power delivered to it. Power is voltage times current, so the more the current, the more the light.

Cheap lights use three AAA batteries for a 4.5V supply. A simple resistor is used to limit the current and drop the voltage down to the required 3.2 volts. This is what you might refer to as "direct drive". In this case, as the batteries wear out, their voltage drops so the amount of current delivered also drops so the light gets dimmer.

A single Lithium cell produces a little over 3 volts when its fresh. Key chain lights using a small lithium cell will forgo the limiting resistor. Small batteries have a large internal resistance which limits the current to safe levels. But battery life is short this way as the battery voltage will quickly drop down below the threshold to make the LED work. But since key chain lights are used for short periods of time, this isn't a big deal.

Adding an electronic regulator between the battery and LED allows using lower voltage batteries, like a single AAA or lithium since these circuits can boost the voltage and it can be used to control the current providing a more consistent light output and extending battery life.

But they have the disadvantage of giving little or no warning the battery is about to go really dead. Since it's pretty much impossible to keep track of how many hours you have on your light, it can come as a surprise when it does go out.

[Five Tango]

FourSevens makes flashlights that run off AA's that are programmable from just enough light to see a keyhole to a whopping 205 lumens.Battery life is dependent on the lumen power you select.Once mine no longer puts out the full power 205 it will give the next setting for a long time before the batteries are dead.But it is a handheld and not a head lamp.I have used mine daily for several years now-worth the money.