Battery and run time terminology

Dear all,
I am not clear on the meaning of a couple of terms and would be very grateful of some help -
Firstly with respect to run times - wolf eyes sometimes refers to run times for their lights on regulated or unregulated - the unregulated being longer by a factor of 2. Just what does this mean? I thought at first it was run time at full power and then at a lower power but this doesn't seem to make sense.
Secondly I often hear the terms of protected and unprotected when referring to rechargeable batteries. I think this means that protected batteries have circuitry in them that stops the battery dischargeing too much - thus maybe causing permanent damage to the cell. This sounds like a good thing - but does it mean the battery gives up less of its charge than an unprotected battery - hence effectively being a smaller capacity. Just what are the pros and cons of the two types
Many thanks in advance

A regulated light maintains the same brightness, where unregulated slowly dims down as the batteries are used up.

Protected cells have the circuit you guessed, which protects the battery from over discharge, over charge, etc. By the time the protection circuit kicks in, you have already used up most all of the available juice, so drawing it down any further without a protection circuit won't get you much more runtime and it can be dangerous.

Iain you were right the first time. WE is quoting how long the light will run in regulated mode and then the additional run time in unregulated mode once the batteries drop in voltage below the regulator's minimum operating level. The reason the run time in unregulated mode is so long, is that as the voltage drops more and more, the current draw to the LED also diminishes and so you have less and a less of a load on the batteries making it harder to fully discharge them. What you don't see and they can't publishe without a full run time chart is the drop off in light output for that very long unregulated run time to where it would be so much less than original power and down to where it may not even be useful. But this is a normal thing to publish. They are telling you basically the light will run longer than just the full power level on those batteries.

Protected batteries have circuitry to prevent them from discharging past a point that the vendor has determined will degrade the battery and shorten its overall all life. Less charge taking ability, less charge cycles, dies sooner. So if you don't discharge it past that point and recharge it, you get better charge, longer run time per charge, and more recharge cycles in general.

Some flashlights however draw so much current from the batteries that the protected ones simply will not work, so then you have to use the unprotected ones and know not to run them till they are dead, unless its an absolute necessity.

I do believe that the protection circuit eats up a little space and because it actually cuts off the battery at a certain level, gives you less overall run time than a nonprotected cell, but in the long run, it will work and last longer if properly maintained. Thats the general theory anyway.

brilliant guys - concise and clear (just the sort of illumination one would expect on a forum of such enlightened flashaholics). I will have to find out for myself EXACTLY what the unregulated run time does in terms of usable light production - and intend to do so - just paid for a Wolf eyes P7 sniper -

Marduke said:

A regulated light maintains the same brightness, where unregulated slowly dims down as the batteries are used up..

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Is the hardware that does the regulation built into the module containing the emitter? I presume different manufacturers program the regulation differently and that's why a Q5 may put out more or less lumens and have different run times in different lights -- and from different manufacturers, right?

There is usually a group of components on the opposite side of the PC board that the emitter substrate is bonded to. The total current flow can be set by the designer to anything within the working range of the regulator chip and components. typically from 10mA up to 1.1 Amps. Multimode lights have a controller that changes the duty cycle to drive the regulator and step down the current duty cycle on time. Its filtered before it gets to the LED and all you should see is steady state light at different power levels.

There are different types of drivers and different brands. Some step up voltage and some step it down. Some are designed for high current and with high quality and some lesser so. All depends on what you are willing to pay for and what the LED application its designed around.

A lot of this is in the Welome Mat. You might find it useful.

MrGman said:

There is usually a group of components on the opposite side of the PC board that the emitter substrate is bonded to. The total current flow can be set by the designer to anything within the working range of the regulator chip and components. typically from 10mA up to 1.1 Amps. Multimode lights have a controller that changes the duty cycle to drive the regulator and step down the current duty cycle on time. Its filtered before it gets to the LED and all you should see is steady state light at different power levels.

There are different types of drivers and different brands. Some step up voltage and some step it down. Some are designed for high current and with high quality and some lesser so. All depends on what you are willing to pay for and what the LED application its designed around.

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My experience has been a bit different. I've disassembled and modded quite a number of lights, and never seen a regulator on one side of a PC board and the LED on the other. Instead, the designers chose to do what I'd do if I designed a light -- mount the LED on a fairly solid piece of metal (typically via a thermally conductive mounting board or "star"), so that the heat can be conducted away as effectively as possible. Then put the regulator circuitry on a separate board. The regulator board is virtually always close to the LED, so it's in the same "module" or section of the light.

What I've seen for reducing the light level in multi-mode lights are two methods, both different from the method described by MrGman. One is often called "PWM" here. It consists of pulses sent to the LED with differing duty cycles to control the brightness. I've never seen any filtering applied, however, and don't see how it could practically be done in a small space -- I'd be very interested in learning how it might be possible. In the PWM lights I've seen, the pulses are delivered directly to the LED. The eye's retentive characteristic is depened upon to blend the pulses into an apparently constant light level. Some lights like the Fenix L0D have a relatively low pulse rate -- 100 Hz for the L0D -- which some people can perceive as noticeable flicker, and anyone is likely to notice if the light is moved rapidly. Others use a pulse rate up to several thousand pulses per second, so they don't make visible flicker. The second method is simply reducing the steady current sent to the LED by the regulator by controlling the regulator circuitry. This method is always free of flicker.

c_c

torpeau said:

Is the hardware that does the regulation built into the module containing the emitter? I presume different manufacturers program the regulation differently and that's why a Q5 may put out more or less lumens and have different run times in different lights -- and from different manufacturers, right?

Click to expand...

That is exactly right.

For Curious_character. The "duty cycle" I was referring to was Pulse Width Modulation, just in a hurry. The filtering that you don't see or recognize I was referring to is a 10uF capacitor across the output that I have seen in the driver circuit designs. This integrates the duty cycle pulses to the LED to a varying level DC voltage. If they are not all built that way, that's okay. I am sure that there are numerous designs. See the example here. Not my design. I am sure there are others. But that's all you need to integrate the waveform. Maximum current is established by the value of R2.



As to the heatsink under the LED. That was the "substrate" I was referring to under the emitter. The heatsink is typically bonded to the backside of a PC board that has the driver components on the board side and the LED bonded to the heatsink on the other inside of a sealed pill. If they don't all look like that, that's okay to.

C_c, I believe (IIRC) the LF5XT has filtered PWM, which made it unable to dim down quite as low as the LF2-LF5 (which use unfiltered 7.8kHz).