# MDs Rechargeable Compatibility chart/guide for popular flashlights!



## mdocod (Jun 27, 2008)

INTRODUCTION

I've decided to go ahead and put together a computability chart and guide that will help alleviate answering the same questions with lengthy complicated answers in separate threads over and over again. The daily question has become "what RCR123 for "xxx" and which one is best?" The answer is often different for different flashlights, and the answers are often far from simple. However, most of the questions can be answers through a search, but sometimes searching can generate a lot of inapplicable results and frustration.

Before I begin, I'd like to say that I am not intending on including every last flashlight in existence here, I don't think a list of every flashlight on KD/DX is necessary, but there are a number of them that are popular that I will try to add to the list in time. We'll try to focus on popular flashlights across the board, but primarily LED flashlights. I have already covered just about every possible configuration of lamp and body and li-ion cell for tactical incandescent flashlights over here:

MDs Lithium-Ion>Incandecent guide, +compatability/comparison chart

I'd like to do the same thing here, but with focus diverted from modifications, sticking to stock configurations instead. I'll discuss benefits and tradeoffs of different rechargeable chemistries, different types of common regulation found in common LED flashlight, how voltage and capacity effect performance and runtime, then list the behavior of the lights in the compatibility chart on different rechargeable options applicable to the flashlight in question.

This Guide will be a work in progress for as long as I can devote time to it. This thread can be re-located easily as it has been "sticky'd" (Thank You DM51!) to the "threads of interest" for the batteries/electronics section of this great forum 

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COMMON RECHARGEABLE CHEMISTRIES

*NiCD [Nickel Cadmium]:* 
*General Information:*
1.2V Nominal voltage, direct replacement for most consumer devices calling for 1.5V alkaline or 1.2V NiMH cells, available in common consumer cell sizes from AAA to D, also available in non-standard cell sizes for special applications, like Sub-C, A, 2/3A, F etc. 
*Advantages:*
A NiCD cell has the advantage of being extremely robust. They can be overcharged, over-discharged, over-heated, abused with high currents in both directions and have respectable cycle life. (often several hundred cycles or more). 
*Disadvantages:*
The disadvantages of NiCD are it's relatively low energy density, high self-discharge rates and relatively toxic (environmentally unfriendly) contents when compared to more modern chemistries. 
*Charging:*
Charging can be done individually or in series configuration of like capacity cells in similar state of charge, charge termination methods vary widely. Smart chargers will usually use negative delta V style termination, less smart chargers either use a timer to terminate the charge or look for temperature rise. dumb chargers just continue to trickle charge indefinitely until the user removes the cell or device from the charger. the excess charge is converted to heat. Excess charge at slow rates is considered acceptable in most applications but does reduce cell life. Smart chargers will extend cycle life and maintain higher useful capacity through aging than dumb chargers. Pay more for a charger, and buy less cells over the years.
*Discharging:*
There are a wide variety of NiCD cells on the market targeted for different applications. Ordinarily speaking, NiCD can be discharged rapidly, but some application specific cells will perform better than others under high loads. Discharge should ordinarily be terminated at around 0.9-1.0V, then recharged. Occasionally discharging below this level isn't a major concern. Discharging all the way to 0V can be done, I have heard it suggested that this can be done to help improve performance in high drain applications, at the sacrifice of cycle life and capacity. 
*Safety Concerns:*
NiCD cells have a good track record of safety, they are not likely to explode or flame under normal circumstances. Repeated abuse usually just leads to a dead cell. NiCD can violently vent hot gas or leak it's guts if it is overcharged at a very fast charge rate for way too long (or heated up way to much by other means, like repeated charging/discharging at high rate without time to cool.) 
*Myths:*
"Memory effect:" yes, this is a myth. NiCD cells used in standard NiCD chargers and put through typical rigors of various discharge depths will never experience memory effect. 
"1.2V isn't enough to power my 1.5V device:" Total myth in 99% of situations. In reality, under a load, a "1.5V" alkaline cell will fall below 1.2V very quickly, long before the cell is expelled. If you compare a discharge graph of a 1.2V NiCD to an Alkaline cell in most consumer electronics with normal loads (0.5-1A), you'll find that the NiCD will often spend much more of the discharge time above the voltage of the alkaline. 

*NiMH [Nickel Metal Hydride]:* 
*General Information:*
1.2V Nominal voltage, direct replacement for most consumer devices calling for 1.5V alkaline or 1.2V NiCD cells (in some cases), available in common consumer cell sizes from AAA to D, also available in non-standard cell sizes for special applications, like Sub-C, A, 2/3A, F etc. 
*Advantages:*
NiMH is a reasonably safe chemistry that is far less toxic than NiCD, has about double the energy density compared with NiCD, and is available in a wide range of application specific "styles," like "high current capable" "maximum capacity" or "low self discharge." Picking the appropriate NiMH cell for the application is important, with the right type of cell selected, using rechargeable cells becomes a rewarding money saving experience. If you aren't sure which cell is best for your needs, 90% of the time, a Low-Self-Discharge (LSD) is the best option.
*Disadvantages:*
While still tolerant to some abuse, NiMH cells are not generally as robust as NiCD cells. By picking the right cell for the application, and using higher quality charging methods, most of the disadvantages can be overcome. These cells are a bit more sensitive to the extremes like overcharging, over-discharging, etc. While being more energy dense than NiCD, they are still not quite as energy dense as modern Lithium chemistry cells. Some NiMH cells suffer from extremely high rates of self-discharge and are not suitable for long term energy storage. The highest capacity AA/AAA cells are usually the most susceptible to unacceptable rates of self-discharge, which can develop within the first few dozen cycles, making their useful cycle life much lower than suggested by the packaging.
*Charging:*
NiMH cells are best charged by smart negative delta V termination chargers at a reasonable charging rate for the cell in question. They can be charged individually or in series packs containing like capacity cells in a similar state of charge. Charging in the range of 1-6 hours is a good target for charging speed for most cells. Faster charging rates will result in more heat, which can be damaging, but slower charging rates can cause the charger to miss termination signals, which can lead to overcharge. A combination of negative delta V and temperature termination backup can be found on some nice chargers. NIMH cells can be charged by "less smart" and "dumb" chargers just like a NiCD (timer, temperature, or user terminated trickle) but it is less than ideal as these charging techniques will wear out NiMH cells more rapidly. NiMH can expel excess charge as heat and can safely be overcharged at slow rates for long periods of time without danger. Higher quality more expensive chargers will allow cells to live longer healthier lives, buy a quality charger, get more use and a better experience out of your cells.
*Discharging:*
Discharge rates that are acceptable will vary depending on the specific cell. Some can handle very high discharge rates, others perform poorly at high discharge rates. The faster the discharge, the more heat, and the harder on the cell. High current specific cells have lower internal resistance and can accomplish massive discharge rates with less heating. Discharge should be stopped at 0.9V, as far as I know, there is no practical reason to discharge below 0.9V with a NiMH cell, but doing so will not cause any catastrophic problems.
*Safety Concerns:*
NiMH has a good track record of safety, severe overcharging at high rates or repeated charging and discharging at high rates could cause enough heat build-up to make the cell vent hot gas or leak chemical residue. Explosions and fire are highly unlikely in normal use. 
*Myths:*
"Memory effect:" yes, this is a myth. NiMH cells used in standard NiMH chargers and put through typical rigors of various discharge depths will never experience memory effect. 
"1.2V isn't enough to power my 1.5V device:" Total myth in 99% of situations. In reality, under a load, a "1.5V" alkaline cell will fall below 1.2V very quickly, long before the cell is expelled. If you compare a discharge graph of a 1.2V NiMH to an Alkaline cell in most consumer electronics with normal loads (0.2-1A), you'll find that the NiMH will often spend much more of the discharge time above the voltage of the alkaline. And usually last much longer too  

*LiCo02 [Lithium Cobalt Oxide]:* 
*General Information:*
3.7V cells ordinarily found in consumer devices like cell phone, laptops, MP3 players, PDAs, etc. These energy dense cells have found their way into flashlights in recent years as the demand for more compact, lightweight, rechargeable power solutions has gone up. When Someone says "lithium-ion" without stating a specific lithium chemistry this is almost exclusively the chemistry being discussed. LiCo02 cells are available in a variety of sizes including AAA and AA and CR123 size, but they use a different naming structure for size labeling. The size of the cell is described in a string of numbers that define the dimensions in millimeters. So a AAA li-ion cell is a 10440. (10mm x 44mm x "cylindrical"). AA = 14500. CR123 = 16340. other common sizes: 17500, 18500, 17670, 18650. These are NOT USUALLY compatible with devices that call for a 1.5V or 1.2V alkaline/NiCD/NiMH, however, there are SOME flashlights on the market that ARE compatible with the higher voltage. Most flashlights that are compatible with them, will indicate so in the product details. These should never be considered direct replacements for 3V CR123 primary cells as they have substantially higher operating voltage. Always check for compatibility with the higher voltage on devices before using them. There are a large number of LED flashlights that are compatible, and a number that are not.
*Advantages:*
Highest available energy density commonly found in rechargeable cells. Especially in the larger sizes, 17500 and up. Very efficient charging and discharging with the least amount of energy expelled as heat. Higher per-cell voltage means less cells are needed to achieve certain voltage requirements. When treated properly, these have exceptional cycle life (hundreds+). Li-Ion also has exceptionally low self discharge. 
*Disadvantages:*
Smaller size Li-Ion cells, like 14500, RCR123 (16340), and 10440, do not generally live up to their label capacity claims and usually have lower energy density than alternative chemistries in the same size. LiCo02 is not tolerant to abuse, these cells must be used within the bounds as listed by the manufacture. Rapid charging (faster than 1 hour) and rapid discharging (faster than 30 minutes) is not possible with these, so they are not necessarily as flexible as Nickel chemistry cells. In order for loose li-ion cells to be used in devices like flashlights, they need to have protection circuits installed for safety reasons, which adds a layer of potential failure to the device. Li-Ion is more prone to vent-with-flame/explode than Nickel chemistry cells if abused. LiCo02 also suffers from the effects of aging whether it is being used or not, though in recent times, this has becomes less and less of a factor with li-ion cells. Used to be that they would be considered "dead" after a few years from production whether they were used or not. Now they seem to be lasting 7-10 years without much trouble.
*Charging:*
The proper charging technique for LiCo02 must be followed to tight specification for maximum safety. The cell should be charged at a 1C or slower rate at a constant current until the cell reaches 4.20V, at which point the charger should hold 4.20V (constant voltage) until the charge current drops to some fraction of the original charge current (usually around 0.05C give or take) (varies from charger to charger, but there is probably an ideal termination current based on cell capacity that would be impossible to have perfect on a charger designed for multiple cell sizes). Charging in series packs can only be done properly with balance taps on the pack and a balance charger. Li-Ion cells in a similar state of charge can be charged in parallel as if they were a single cell. Charging above 4.20V will cause increased rate of internal oxidation, reducing effective cycle life and capacity, while simultaneously increasing the risk of explosion/fire. 4.30V will not usually cause an immediate danger, this is where most protection circuits will kick in. Use a high quality charger to perform charging if possible. Most cheap chargers do not follow the proper charging requirements. The Pila ICB is most often recommended and is worth the $40 or so.
*Discharging:*
LiCo02 cells should not be discharged below ~3.0V under a load, (varies by manufacture). A good rule of thumb is that when the cell reaches ~3.5V open circuit, it is dead and should be recharged. Over-discharging a cell will increase the rate of internal oxidation leading to reduced capacity, reduced cycle life, and increased likelihood of explosion/fire. Different cells are rated for different maximum discharge rates, usually specified between 1.5 and 2C. (C ratings are having to do with time, a 2C rating, means 30 minutes, 1C means 1 hour, 4C means 15 minutes, 0.5C means 2 hours, etc etc, bigger C). Check to see what your cells are rated at and use them in an application that is within the bounds of the maximum discharge rate. 
*Safety Concerns:*
Abusing these cells by overcharging, over-discharging, discharging too quickly or charging too quickly, or causing physical damage of sorts can increase the risk of fire/explosion. These cells need to be treated with a higher level of respect and care than NiMH or NiCD. Use protected cells whenever possible to reduce the risk of an incident. Keep in mind that li-ion is most apt to flame/explode while charging, not while discharging, so to maximize the safety of a questionable cell, charging in a fireproof box in a well ventilated area is recommended. A flaming/exploding LiCo02 cell releases Hydrofluoric acid. Breathing the gas or coming into direct contact with the remnants of a LiCo02 fire can cause severe poisoning that can cause major illness or death. 
*Myths:*
"I have a protection circuit, so don't have to worry about over-charging or over-discharging." This is the most common misunderstanding. The protection circuit is set to prevent dangerous events from occurring, it does not prevent smaller scale overcharging and over-discharging. They are often set at ~2.5V and ~4.3V whcih would not be healthy termination points for normal cycles.
"My cell is rated at 900mAH and 2C, so it can handle a 1.8 amp discharge." (I was guilty!)
The C ratings assigned are based on time, not label capacity. In reality, there are many 900mAH RCR123 size cells out there that are actually only good for 500mAH capacity or less at 2C, which means their maximum discharge rate is only 1 amp. 

*LiFeP04 [Lithium Iron Phosphate]:* 
*General Information:*
Often sold as 3.0V rechargeable cells, these are technically 3.2V li-ion cells based on a new cathode material that is inherently safe. These cells can *often* be used as a direct replacement for CR123 primary cells in lights that can tolerate the slight voltage difference compared with primary cells. (keep in mind, that primary CR123s actually operate below 3V when under a load, more like 2.5V). For the most part, LED lights that normally run CR123s can run these no problem, incans usually can not unless regulated (rare). LiFeP04 cells are currently available in only a few sizes, including "RCR123" (16340) and 18650 and few others we won't discuss at this time. I lean towards recommending these over the 3.0V regulated cells discussed below.
*Advantages:*
Safe chemistry won't explode or flame, can tolerate some abuse without too much issue, does not need protection circuit like LiCo02 to be used in consumer devices, so less failure points. Higher voltage per cell than NiMH/NiCD means less cells are required to achieve voltage desired, can often be used where 3.7V cell is not advisable. Offers a safer more reliable alternative to 3.0V voltage regulated LiCoO2 cells.
*Disadvantages:*
Much lower energy density compared to LiCo02, generally speaking, around 50% less stored energy per volume. Needs special LiFeP04 charger, one more device to have floating around. Label capacities are generally way overstated on smaller cells. Expect 200-400mAH from 16340 size cells depending on load. For comparison purposes, a CR123 primary has between 1200 and 1500mAH capacity. So these will really hurt runtime. 
*Charging:*
Charging rate is fairly flexible on these, most small RCR123s in this chemistry are sold with matching charger that charges in an hour or a few hours. Charge is usually just constant current until voltage reaches about 3.6-3.8V (varies by manufacture) followed by some constant voltage until the current drops to around 0.05C give or take. (when charged CC to 3.8V it's probably pretty close to full, when terminating at 3.6V, some CV is probably required to finish the charge) overcharging won't cause too much damage provided it isn't done too rapidly or for too long. A LiFeP04 cell can be charged in a "4.2V" LiCo02 charger in a pinch, but you would want to pull the cell manually sometime around 3.8V if possible(use volt-meter to check). As far as I understand, these can be charged in series or parallel most of the time, but should be isolated on occasional charges to balance them out. (I could be wrong on this)
*Discharging:*
Discharge capabilities vary by cell manufacture and size. Larger scale LiFeP04 cells were originally intended for use in high drain applications like power tools and electric cars. Small scale LiFeP04 cells aren't quite as tolerant to high discharge rates and tend to "fall on their face" at discharge rates higher than ~2-3C. But Discharging even the small cells at higher than recommended rates is still not really dangerous, just wears out the cells more quickly. Discharge should be terminated at 2.0V whenever possible. Discharging below 2V will degrade the cell more rapidly, some cells seem to be more tolerant to over-discharging than others.
*Safety Concerns:*
Very few issues of safety, I would classify them as similar in safety to NiCD/NiMH cells, major heating from constant abuse might cause a hot gaseous venting or leak, but this chemistry does not typically ignite.
*Myths:*
"It's a 3V cell so will work in any device designed for CR123 primaries."
They will work in most devices, but any direct drive incandescent will likely blow it's bulb on these cells. 

*3.0V RCR123s not labeled LiFeP04:* 
*General Information:*
These are usually 3.7V LiCo02 RCR123 cells that have a voltage regulator installed to shunt the operating voltage down to around 3.0V to make them more compatible with voltage sensitive devices. These are often the alternative to the LiFeP04 cell, or you could say, that the LiFeP04 cell is the alternative to this. Most of these cells are sold as protected cells, but I just found one the other day online that is voltage regulated but NOT protected. I highly recomend picking protected versions of this type of cell if you decide to use them. Overall I lean towards recommending the LiFeP04 cells for applications where these are often specified. 
*Advantages:*
Can often work where 3.7V cells would not. Usually has slightly better capacity compared to LiFeP04 RCR123s.
*Disadvantages:*
More components to fail. The voltage regulating component of these generates heat right next to the cell, which is less than desirable for cell longevity. The cell itself has to be smaller to make room for additional components, or the cell ends up being too long for some devices. Accidentally putting a 3.7V cell into a charger designed for these would probably cause an explosion. Not a good charger to have floating around in a collection of various cells and chargers and devices. 
*Charging:*
Charging must be done on the charger that is sold with the cells or recommended for the cells as these things vary from one manufacture to the next on their recommended charge voltage termination from 4.4-4.5V. The cell itself still needs to be terminated at 4.20V, but the charger has to overcome the voltage regulation device "backwards" through the circuit, so to speak, (if that makes any sense). Do NOT use one of these chargers on any cell other than the cells it is sold with!!!
*Discharging:*
Often limited by the voltage regulating device to around 1-2C, discharging continuously above 1C IMO could cause overheating of the cell or failure of the voltage regulator. Discharge should be terminated at around 2.0-2.5V give or take (follow manufacture recommendations).
*Safety Concerns:*
Same as LiCo02 cells above. Abuse can lead to vent with flame, these are IMO more susceptible because of that heat making deice attached to the cell. 
*Myths:*
"It's a 3V cell so will work in any device designed for CR123 primaries."
They will work in most devices, but any direct drive incandescent will likely blow it's bulb on these cells. 

*LiMnO2 / LiMn2O4 / "IMR" / LiNiMnCoO2 [various Lithium Manganese Oxide type cells]:* 
*General Information:*
3.6-3.8V cells ordinarily found in Power tools. These cells have found their way into flashlight applications for various reasons. Their properties are similar to LiCoO2 cells in many ways, but with a few key differences. These cells are not available with protection circuits on individual cells, but are considered "safe" chemistry cells, similar in safety to a LiFePO4 or NIMH cell.
*Advantages:*
Excellent balance of energy density and power density. Capable of driving loads that LiCoO2 cells can not safely handle. Safe chemistry means they will not fuel their own fire in the event of a catastrophic failure with oxygen. 
*Disadvantages:*
Lower Energy Density than LiCoO2 cells.
*Charging:*
Charging requirements are basically the same as most LiCoO2 cells, 4.20V termination for most LiMnO2 cells is common. There are a few LiMnO2 chemistry cells found in power tools that need to have their charge terminated at 4.10V rather than 4.20V, but at the time of writing this, the only "consumer oriented" loose cells available are from AW, and they will charge fine in MOST 3.7V li-ion chargers. Over-charging will dramatically reduce cycle life and severe over-charging could cause the cell to "pop." These cells can usually handle faster charging rates than LiCoO2 cells, check the specifications on your specific cells for more clarity on this issue. 
*Discharging:*
The minimum discharge voltage and maximum recommended discharge rates, continuous and pulse, vary by manufacture. Generally speaking these cells can handle very aggressive discharge rates without much trouble, 5-10C range is common for the upper end limit. Discharge should be terminated at ~2.5-3V under a load, shallow discharges are healthier for these cells just like for LiCoO2 cells. 
*Safety Concerns:*
Nothing too serious, similar to NIMH/NiCD/LiFePO4 safety concerns. When overheated or overcharged or repeatedly abused they could pop and/or vent gas. Ignition is unlikely but theoretically possible under the right circumstances, but the fire would not be fueled by a chemical reaction from the cell like in the case of a LiCo cell, so it would be a far less aggressive failure. 
*Myths:*
"These are safe chemistry cells, so I can use them in anything!"
Flashlights that contain regulation circuits can over-discharge these cells severely. While over-discharging may not create any immediate danger, it will severely reduce the useful life of the cell. There are exceptions to every rule, some LED lights would be perfectly fine with LiMnO2 cells, some configurations becoming available will actually require them to handle the current demands safely, but each situations should be looked at individually.

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Common types of "regulation" circuits in LED lights

_*My hope is that by having a quick summery of each type of common regulation (or lack there-of) found in LED lights, readers can better understand the reasons behind the behaviors of their lights on the various rechargeable options. *_

*direct drive:*
Ok, so this isn't a regulation type, it is a lack of regulation type. I personally classify any light that lacks a regulator, but may have a simple resistor, a direct drive light. In a direct drive light, output will decline through the run. The resistor, or the Vf of the LED is selected such that the maximum current the LED sees is at the beginning of the run on fresh cells, and is set to something reasonable for the LED to handle, it's all down hill from there. Generally speaking, a direct drive light that was intended for use with alkaline cells (almost always 3 cells) will work fine on NiMH or NiCD, the rechargeable chemistry will actually help stabilize the output through the run, making the discharge curve more useful. Some direct drive lights run on a pair of CR123s, this is pretty uncommon but I have seen a number of them on cheapo lights from places like DX/KD. On these lights, the only way to switch to a rechargeable cell would be to switch out the resistor to a different value. Sorry, there is no direct drop-in solution to making a direct drive 2xCR123 light rechargeable.

*buck:* 
Buck style regulation takes a voltage input higher than the Vf of the LED, and bucks it down to match the LED and hold a set current across it. Often times these lights are sold as 2xCR123 lights, but are often compatible with higher voltage input from a pair of 3.7V cells without any problem. 3.0V rechargeable cells could also be used, but the 3.7V protected cell option will provide the best runtime and performance. Buck style regulated lights drop out of regulation when the voltage of the battery/s drops down close to the Vf of the LED. With buck regulation, it's usually better to move up in source voltage rather than down when seeking out rechargeable solutions as they can ordinarily handle it. (always check compatibility before attempting) 2xCR123 powered lights with buck regulation can often take a single 3.7V 17670 (or 18650, if there's room) as a power source, but the light will operate as a direct drive light through most of the discharge. This extends runtime at the cost of flat regulation. In many cases, running a buck-regulated light on a single li-ion cell will result in both lower beginning brightness, and diminishing output through the run, it depends on the specific nature of the regulator and the Vf of the LED. 

*boost:*
Boost regulation takes a voltage below the Vf of the LED, and pulls extra current from the battery and converts it to a higher voltage to drive the LED. This type of regulation is found in most 1xAA, 2xAA, and 1xCR123 lights. When the input voltage rises above the Vf of the LED, the regulator is essentially bypassed with minimal resistance and the battery direct drives the LED. So most boost regulated 1xAA and 1xCR123 lights are NOT entirely compatible with a 3.7V li-ion cell as it will remove all lower operating modes and overdrive the LED. How much the LED is overdriven depends on the Vf of the LED, this is luck of the draw so one persons light may survive a 3.7V cell, while the next persons will not. In order to maintain access to all modes, and not risk damaging the flashlight, a 3.0V rechargeable cell (LiFeP04 or V-regulated) is recommended for 1xCR123 lights, or a NIMH or NiCD cell/cells for AA lights. Putting a pair of 14500 3.7V cells in a 2xAA light will instantly blow the LED, don't bother. 

*buck/boost:*
Some lights have the advantage of being capable of either boosting or bucking voltage within a limited range. This can be a good and bad thing depending on the situation. Usually these types of regulators have a narrower band of voltage input compatibility than buck regulators, but make ideal solutions for power sources that will be above or below the Vf of an LED depending on state of charge or power source selected. These come in 3 dominant types. Found in 1xAA and 1xCR123 lights the voltage input range is usually ~0.9V-~4.2V, which allows the light to run on any single alkaline, NiCD, NiMH, CR123 or RCR123 of any available voltage (1.2V up to 3.7V cells). another style is typically compatible with ~2.5V-6V input, so is usually found in 2xCR123 length lights, but will work well on a single 3.7V cell of the same length as the 2 CR123s, or 2 3V CR123s (a 17670 or 18650, if bored to accept 18650 that is the preferred choice), these type of regulars are often picky about voltage above 6V and will not work properly on a pair of rechargeable 3.0V cells as their operating voltage is usually higher than 3V per cell when fresh from the charger. Another common buck/boost is designed for ~2.7-4.2V operation, and is designed specifically for use with a 3.7V cell, these are almost exclusively found in 1x18650 powered lights and should only be fed a 3.7V 18650 as a power source. 

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Voltage, Amp hours, etc...

_A quick overview of how common electrical characteristics translate to their behavior in flashlights should improve the overall experience here. Most of this is covered in the Welcome Mat and probably in a billion others threads here and a gazillion websites on the Internet, but, we can never be too sure, so here we go _

The best analogy I can think of to explain voltage and current as it pertains to a battery is a water tower. The higher up in the air the water tower is, the more pressure there will be available at the base of the tower at the pipes. The more pressure, the more water can be forced through a given size pipe of fixture. The pipes that the water is forced through are like the resistive load that a battery pushes electrons through. 

Think of mAH (mili amp hours, amp hours etc) as the size of the tank on top of the tower. A bigger tank will supply water for a longer period of time. More mAH means the flashlight runs longer.

When you add cells in series, it's like taking the poles that are holding up the tower, and stacking all the poles on top of each-other, and putting the tank on top of all of those poles, the tank stays the same size, but is raised to a higher elevation, more pressure. More voltage. Two 3V 1300mAH cells in series makes 6V battery with the same 1300mAH mAH capacity.

When you add cells in parallel, it's like putting more tanks in the air, but at the same elevation as the original tank, so the new battery has more storage capacity, but the same amount of pressure available. Two 3V 1300mAH cells in parallel makes a 3V battery with 2600mAH capacity.

We can represent the combination of pressure and tank size as watt-hours by multiplying voltage by amp-hours. A 3V cell with 1300mAH capacity can be said to have 3900mWH (mili watt hours), or, 3.9 Watt Hours (WH). This is useful for comparing total energy storage of different arrangements of different types of cells.

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On a side note, It's important to note that label ratings on cells should not always be trusted, just because one brand claims more mAH than another does not mean it is always true. Since many of the flashlights in the compatibility chart will be dealing with RCR123 size cells, I think it's important to note that these are pretty much all 500-650mAH true capacity regardless of what the label says. Before making a purchase decision based on manufacture claims, it would be wise to take a moment to look over many of the tests that have been run no various cells by some of our own beloved CPF members. Check out the "threads of interest" here in the Battery's/Electronics section for a number of links to these tests. Also keep in mind that not all RCR123s are the same size as a CR123 cell, some are a little longer or fatter, so they might have slightly better capacity ratings, but might not fit in some lights. 

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That's enough for the guide, for now, I'm sure I'll add more and revise this many times in the future so stay tuned 

Eric


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## mdocod (Jun 27, 2008)

Compatibility Chart

Please feel free to ask for any additions to the compatibility chart, I'll do my best to include them in the chart and make a best possible rechargeable recommendation 

_Organized by brand, alphabetically._

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*Fenix:*

*LOD/(CE)*
Battery Size: AAA
Regulation Type: Boost
Recommended Input Voltage Range: 0.9-3.0V (estimated)
Recommended Rechargeable option: 1.2V LSD NIMH. Improved runtime over alkaline, good overall performance, no compatibility issues. 
Rechargeable alternatives: 
1. 3.7V 10440 Li-Ion. Direct drives LED harder than normal operation, looses low modes, pushes li-ion cell beyond 2C discharge rate. Only available in unprotected cell. (eek)
2. High capacity NIMH. 
3. NiCD

*EO1*
Battery Size:AAA
Regulation Type: Boost
Recommended Input Voltage Range: 0.9-3V (estimated)
Recommended Rechargeable option: LSD NIMH
Rechargeable alternatives: 
1. high capacity NIMH. 
2. NiCD.

*L1D/(CE), L1T*
Battery Size: AA
Regulation Type: Boost
Recommended Input Voltage Range: 0.9-3V (estimated)
Recommended Rechargeable option: LSD NIMH
Rechargeable alternatives: 
1. protected 3.7V 14500 size li-ion, Direct drives LED harder than normal operation, looses low modes, risks overdriving or overheating LED, may be especially hazardous to units that ship with lower than average Vf LEDs. 
2. High capacity NIMH
3. NiCD

*L2D/(CE), L2T, EO2*
Battery Size: 2xAA
Regulation Type: Boost
Recommended Input Voltage Range: 0.9-3V (estimated)
Recommended Rechargeable option: LSD NIMH
Rechargeable alternatives: 
1. High capacity NIMH
2. NiCD
*Do not use 3.7V 14500 Li-Ion cells!

*P1/(CE)*
Battery Size: 1xCR123
Regulation Type: Boost
Recommended Input Voltage Range: 0.9-4V (listed)
Recommended Rechargeable option: 3V LiFeP04 RCR123
Rechargeable alternatives: 
1. 3V regulated LiCo02 RCR123
2. protected 3.7V RCR123; will direct drive LED above normal level of operation, could cause overheating and overdrive damage in batches with low Vf emitters.
*All rechargeable options will have substantially reduced runtime compared with CR123 primary. 

*P1D/(CE), P2D*
Battery Size: 1xCR123
Regulation Type: Boost
Recommended Input Voltage Range: 0.9-3V (estimated)
Recommended Rechargeable option: 3V LiFeP04 RCR123
Rechargeable alternatives: 
1. 3V regulated LiCo02 RCR123, may provide more runtime 
2. protected 3.7V RCR123; will direct drive LED above normal level of operation, could cause overheating and overdrive damage in batches with low Vf emitters. Loss of all low modes.
*All rechargeable options will have substantially reduced runtime compared with CR123 primary.

*P3D, T1, TK10*
Battery Size: 2xCR123
Regulation Type: Buck
Recommended Input Voltage Range: 5-9V (estimated)
Recommended Rechargeable option: 2x 3.7V protected RCR123
Rechargeable alternatives:
1. 1x17670 size 3.7V protected li-ion. Will not run in regulation, battery low indicator turns on prematurely.
2. 2x 3V LiFeP04, worse runtime compared with 2x3.7V RCR123
3. 2x 3V regulated LiCo02, reduced runtime compared to 2x3.7V RCR123, more components to fail.
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

*TK11*
Battery Size: 2xCR123
Regulation Type: Buck (seems to be the consensus)
Recommended Input Voltage Range: 3V-8.4V (estimated)
Recommended Rechargeable option: 1x 18650 protected 3.7V li-ion.
Rechargeable alternatives: 
1. 1x 17670 protected 3.7V li-ion. (reduced runtime, why bother? maybe have some laying around?)
*Supposedly compatible with 2x3.7V RCR123s if you want flat regulated output with shorter runtime while maintaining recharge-ability. Runs with continuously diminishing output on 1x18650.
*This flashlight can over-discharge unprotected li-ion cells if used with 2x3.7V cells, including "IMR" cells. Use only protected cells in this configuration!

-------------------------------------------------------

*Inova*

-------------------------------------------------------

*JetBeam:*

*M1X*
Battery Size: 3xCR123, 3xRCR123, 2x18500,
Regulation Type: unknown at this time
Recommended Input Voltage Range: 6.5-18V
Recommended Rechargeable option: 2x protected 18500
Rechargeable alternatives:
1. 2x protected 3.7V 17500
2. 3x protected 3.7V RCR123s

*M1X w/extender*
Battery Size: 4xCR123, 4xRCR123, 2x18650
Regulation Type: unknown at this time
Recommended Input Voltage Range: 6.5-18V
Recommended Rechargeable option: 2x protected 18650
Rechargeable alternatives:
1. 2x protected 17670
2. 4x protected 3.7V RCR123

*Element/E3P*
Battery Size: 1xAA
Regulation Type: Boost
Recommended Input Voltage Range: estimated 0.7-3V
Recommended Rechargeable option: LSD AA NIMH
Rechargeable alternatives:
Any NIMH/NiCD AA cell
*This light does not support 3.7V 14500 cells, do NOT use them!

*Jet I Pro EX w/IBS, Jet I Pro EX V2*
Battery Size: 2xAA
Regulation Type: boost
Recommended Input Voltage Range: 0.7-4.2V
Recommended Rechargeable option: 2x LSD NIMH cells
Rechargeable alternatives: Any other NIMH or NiCD AA cells
*Do not use 2x14500 3.7V cells, you will fry this thing!

*Jet I Pro/ w/IBS*
Battery Size: 1xAA
Regulation Type: boost
Recommended Input Voltage Range: 0.7-4.2V
Recommended Rechargeable option: 1x protected 3.7V 14500
*this is one of the few 1xAA flashlights that gets a major boost from running a 3.7V cell, worth it if you want a 1xAA screamer!
Rechargeable alternatives:
1. 1xLSD AA NIMH cell (also a great option if you want more runtime than a 3.7V cell)
2. Any NiMh or NiCD AA cell
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

*Jet II Pro, Jet II w/IBS*
Battery Size: 1xCR123
Regulation Type: boost
Recommended Input Voltage Range: 0.7-4.2V
Recommended Rechargeable option: 1x3.7V protected RCR123
Rechargeable alternatives: none worth mentioning.
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

*Jet III series (standard, 1x18650 versions)*
Battery Size: 1x18650
Regulation Type: boost
Recommended Input Voltage Range: 0.7-4.2V
Recommended Rechargeable option: 1x protected 3.7V 18650
Rechargeable alternatives: 1x protected 3.7V 17670
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

*Jet III series (broad voltage or Military)*
Battery Size: 2xCR123, 2xRCR123, 1x18650
Regulation Type: buck
Recommended Input Voltage Range: 2.7-15V
Recommended Rechargeable option: 1x protected 3.7V 18650
*will produce long runtime with diminishing output through the discharge)
Rechargeable alternatives: 2x3.7V protected RCR123s. 
*this will provide better regulation with much less runtime
*This flashlight can over-discharge unprotected li-ion cells when used in 2x3.7V configurations, including "IMR" cells. Use only protected cells!


**
Battery Size:
Regulation Type:
Recommended Input Voltage Range:
Recommended Rechargeable option:
Rechargeable alternatives:


-------------------------------------------------------

*LumaPower:

LM31, LM301, **ConneXion, **Formula One F1
*Battery Size: 1xAA
Regulation Type: boost
Recommended Input Voltage Range: 0.8-4.2V
Recommended Rechargeable option: 1xLSD NIMH AA
Rechargeable alternatives:
1. 1x 3.7V protected 14500 LiCoO2, Low mode will loose proper function on some of these lights (it's still a "lower" mode, but isn't as low as it's "supposed" to be, low mode operates very inefficiently on the 3.7V cell also, use 3.7V cells primarily for maximizing performance in high mode and consider a 1 stage switch replacement where applicable)
2. Any alternative NiMH or NiCD AA cell.
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!


*M3 Transformer
*Battery Size: 1xCR123, 1xAA, 2xAA
Regulation Type: boost
Recommended Input Voltage Range: 0.8-4.2V
Recommended Rechargeable option: 
1. 1x protected 3.7V RCR123
2. 1x LSD NIMH AA
3. 2x LSD NIMH AA
4. 1x protected 3.7V 14500
Rechargeable alternatives:
1. 1x 3.0V LiFeP04 RCR123 (much less runtime)
2. 1x 3.0V "voltage regulated" LiCoO2 RCR123 (less runtime)
3. 1x or 2x alternative NIMH or NICD
*Do NOT use 2x 3.7V 14500 cells in this light, it will cook the electronics.
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells if using a 1x li-ion configuration!


*LM33, LM303, **IncenDio, M3 Transformer, D-Mini Series*
Battery Size: 1xCR123
Regulation Type: boost
Recommended Input Voltage Range: 0.8-4.2V
Recommended Rechargeable option: 1x protected 3.7V RCR123
Rechargeable alternatives:

1. 1x 3.0V LiFeP04 RCR123 (much less runtime)
2. 1x 3.0V "voltage regulated" LiCoO2 RCR123 (less runtime)
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

*D-Mini +D65 Extender*
Battery Size: 1x18650
Regulation Type: boost
Recommended Input Voltage Range: 0.8-4.2V
Recommended Rechargeable option: 1x protected 3.7V 18650 LiCoO2
Rechargeable alternatives: none worth mentioning*
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

D-Mini +2xAA Adapter*
Battery Size: 2xAA
Regulation Type: buck/boost
Recommended Input Voltage Range: 0.8-4.2V
Recommended Rechargeable option: 2x LSD NIMH AA
Rechargeable alternatives: 2x alternative NIMH/NICD 
*DO NOT use 2 3.7V 14500 cells, it will cook the electronics.*

Avenger*
Battery Size: 1xAAA
Regulation Type: boost
Recommended Input Voltage Range: 0.8-4.2V
Recommended Rechargeable option: 1x LSD NIMH AAA
Rechargeable alternatives:
1. 1x Alternative NIMH/NICD
2. 1x 3.7V 10440 LiCoO2, provides substancially higher output but unprotected cells are all that is available in this size, user must take precautions to ensure that the cell is not overdischarged during use, or overcharged during charging.*

M1, MRV*
Battery Sizes: 2xCR123, 1x18650
Regulation Type: buck
Recommended Input Voltage Range: ~3.8V-9V (estimated)
Recommended Rechargeable option: 
1. 1x 3.7V protected 18650 LiCoO2 (longest runtime, diminishing output)
2. 2x 3.7V protected RCR123 LiCoO2 (short runtime, fully regulated at max output through run) Rechargeable alternatives:
1. 2x 3.0V LiFeP04 RCR123 (much less runtime, stays in regulation)
2. 2x 3.0V "voltage regulated" LiCoO2 RCR123 (less runtime, stays in regulation)
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells if used in the 2x3.7V configuration!

*MRV+ M-65 adapter*
Battery Size: 2x18650
Regulation Type: buck
Recommended Input Voltage Range: ~3.8-9V (estimated)
Recommended Rechargeable option: 2x 3.7V protected 18650 LiCoO2
Rechargeable alternatives: none worth mentioning
*DO NOT use 4 CR123/RCR123 size cells of ANY type, it will exceed maximum input voltage and fry the electronics
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

-------------------------------------------------------

*Olight:*

*T25 series*
Battery Size: 2xAA
Regulation Type: boost
Recommended Input Voltage Range: 1.0-4.0V (manufacture recommended)
Recommended Rechargeable option: 2 AA LSD NIMH
Rechargeable alternatives:
1. Alternative AA size NIMH/NICD cell.
*DO NOT use 2 3.7V li-ion cells in this flashlight, it will destroy the electronics!

*T15 series (or T10 with a T15 battery tube)*
Battery Size: 1xAA
Regulation Type: boost
Recommended Input Voltage Range: 1.0-4.2V (estimated)
Recommended Rechargeable option: 1x LSD AA NIMH cell
Rechargeable alternatives:
1. Alternative AA size NIMH/NICD cell.
2. 1x 3.7V protected 14500 LiCoO2 cell.

*T10 series (or T15 with a T10 battery tube)*
Battery Size: 1xCR123
Regulation Type: boost
Recommended Input Voltage Range: 1.0-4.2V (estimated)
Recommended Rechargeable option: 1x 3.7V protected RCR123 LiCoO2 cell. 
Rechargeable alternatives:
1. 1x 3.0V LiFeP04 RCR123 (much less runtime)
2. 1x 3.0V "voltage regulated" LiCoO2 RCR123 (less runtime)
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

*T20 series*
Battery Size: 2xCR123
Regulation Type: buck
Recommended Input Voltage Range: 4.5-9.0V (estimated)
Recommended Rechargeable option: 2x 3.7V protected RCR123 LiCoO2 cells.
Rechargeable alternatives:
1. 2x 3.0V LiFeP04 RCR123 (much less runtime)
2. 2x 3.0V "voltage regulated" LiCoO2 RCR123 (less runtime)
*I do not recommend the use of a 17670 cell here as it will probably cause the light to be constantly flashing to indicate low battery, not to mention, it will not run in regulation at full brightness on a single 3.7V cell. The Olight T20 series does not appear to be bored for use with 18650s (why bother if it's not going to run on that voltage range anyways right?)
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells if used in a 2x3.7V configuration. Use only protected cells!


-------------------------------------------------------

*SureFire:

*Surefire does not specify compatibility with rechargeable cells on any of their non-rechargeable lights, using rechargeable configurations in SF lights should be considered "at your own risk." Damage caused by using cells not specified for use by SureFire could void warranty and can cause damage in some lights if the wrong rechargeable solution is chosen.
* 
*E1B, E1L, L1 etc (this should apply to both older luxeon and modern cree/seoul 1xCR123 powered SureFire lights)
*Battery Size: 1xCR123
Regulation Type: boost
Recommended Input Voltage Range: 0.9-3.2V (estimated)
Recommended Rechargeable option: 3.0V LiFeP04 RCR123
Rechargeable alternatives: 
1. 3.0V "regulated" LiCoO2 RCR123
2. 3.7V LiCoO2 RCR123. -will direct drive LED and run brighter than stock, may result in damage to emitter or other components. At mercy of LED Vf, also may loose certain operating modes (where applicable)
*SF battery tubes have pretty tight tolerance, not all RCR123s will fit well. No guarantees.

*G2LED, 6PLED, Z2LED, C2LED, G2ZLED, Or any 2xCR123 size unit utilizing a P60L
*Battery Size: 2xCR123
Regulation Type: buck
Recommended Input Voltage Range: 4-9V (estimated)
Recommended Rechargeable option: 2 3.7V protected LiCoO2 RCR123
Rechargeable alternatives: 
1. 2x 3.0V LiFeP04 RCR123 (least runtime)
2. 2x 3.0V "voltage regulated" LiCoO2 RCR123 (less runtime)
3. 1x 3.7V 17670 size LiCoO2 (drops out of regulation during the run, extended runtime though)
*This flashlight can over-discharge unprotected li-ion cells when used in a 2x3.7V configuration, including "IMR" cells. Use only protected cells!

*G3LED, or any 3xCR123 size "C" compatible SureFire unit utilizing a P60L (examples: 9P, C3) *
Battery Size: 3xCR123
Regulation Type: buck
Recommended Input Voltage Range: 4-9V (estimated)
Recommended Rechargeable option: 2x 3.7V protected 17500 LiCoO2 cells.
Rechargeable alternatives: none worth mentioning.
*This flashlight can over-discharge unprotected li-ion cells, including "IMR" cells. Use only protected cells!

*L2, L4, L5, E2L, E2D LED, (modern cree/seoul versions)
*Battery Size: 2xCR123
Regulation Type: buck
Recommended Input Voltage Range: 3.8-6V (possibly up to 9V)
Recommended Rechargeable option: haven't decided what to recommend yet.
Rechargeable alternatives: 
1. 1x 3.7V protected 17670 will fit some bodies and run with diminishing output through the run, plenty of runtime.
2. 1x 3.7V protected 14670 will fit in any of them and run with diminishing output through the run, good runtime.
3. 2x 3.0V LiFeP04 RCR123s
4. 2x 3.0V "voltage regulated" 3.0V protected LiCoO2 RCR123s
5. I'm still trying to search out the truth on the 9V maximum input voltage here, some people seem to be running some of these on a pair of 3.7V RCR123s, which for a buck-regulated light would be the best option to maintain steady output while having respectable runtime.
*SF battery tubes have pretty tight tolerance, not all RCR123/17670s will fit well. No guarantees. 14670s are the alternative to boring in this case.

*A2 Aviator
*Battery Size: 2xCR123
Regulation Type: buck on incan, "resistored" direct drive on LEDs.
Recommended Input Voltage Range: 4.5-6V (estimated)
Recommended Rechargeable option: 2x 3.0V LiFeP04 RCR123. (may slightly overdrive LEDs but should work fine on the incan side, expect much reduced runtime compared to primaries.
Rechargeable alternatives: none worth mentioning.
*SF battery tubes have pretty tight tolerance, not all RCR123s will fit well. No guarantees.

*Kroma
*Battery Size: 2xCR123
Regulation Type: buck/DD?
Recommended Input Voltage Range: 5-6V (estimated, unconfirmed)
Recommended Rechargeable option: 2x 3.0V LiFeP04 RCR123 (reduced runtime), may slightly overdrive the 5mm LEDs
Rechargeable alternatives:
1. 2x 3.0V "voltage regulated" LiCoO2 RCR123s. should also work
2. read reports of people using 2x3.7V RCR123 but with potential overheating and other damage. 
*SF battery tubes have pretty tight tolerance, not all RCR123s will fit well. No guarantees.

*LuxV based 2xCR123 SureFire's (current U2 and L2, older lights utilizing the KL4 and KL5 heads)
*Battery Size: 2xCR123
Regulation Type: boost (uses a LuxV emitter, which has Vf ranges ~6-7V usually)
Recommended Input Voltage Range: 3.5-6V (estimated)
Recommended Rechargeable option: 1x protected 3.7V 17670 LiCoO2
Rechargeable alternatives: 
1. 1x protected 3.7V 3.7V 18650 LiCoO2 (fits in OLDER U2s, and some with plastic sleeve that can be removed, recent U2s (last few years) have been machined from factory with tighter tolerance to CR123 size, 17670 is the only option there.
2. 2x 3.0V LiFeP04 RCR123s might work in this application, but I wouldn't recommend it.
*Some SF bodies in the older L series were so tight in the battery tube than a 14670 had to be used.

-------------------------------------------------------

*Tiablo:*

-------------------------------------------------------


----------



## Burgess (Jun 27, 2008)

*Thank you*, mdocod, for this Great Information !


You always explain these things very clearly and concisely. :thumbsup:


This thread should be made a " Sticky " !

:twothumbs

_


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## kurni (Jun 27, 2008)

:bow:

Thanks heaps 

A noob like me scroll down and wondered where LiIon was; I guess it's LiCoO2, isn't it?

Kind regards,
Kurni


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## Monocrom (Jun 27, 2008)

Yet another CPF thread bookmarked.

Kudos to you my Good Sir. :twothumbs


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## DM51 (Jun 27, 2008)

Great thread, Eric! Already required reading for all who are unsure about rechargeables, and will be a tremendous resource when completed. I'm adding it to the "Threads of Interest" sticky.


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## geek4christ (Jun 27, 2008)

Awesome work. Thanks for putting all the effort into this and the Lithium-Ion Incandescent Compatiblity Chart. I read through that one several times when I first joined and it looks like this one is chock full of equally great information.


----------



## mdocod (Jun 28, 2008)

Fenix Compatibility added


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## Anders (Jul 6, 2008)

Awesome work mdocod.

Thanks a lot for this one:twothumbs

Anders


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## mdocod (Jul 7, 2008)

Added SureFire LED models to compatibility chart. trying to do some more research to finish it off, if you have a request for a SF LED model that has been "missed" in the chart let me know.


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## X_Marine (Jul 8, 2008)

Great reference dude, Sticky for sure.. :twothumbs

Thanks
X..


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## DM51 (Jul 8, 2008)

This thread is already a sticky insofar as there is a link to it in the "Threads of Interest" sticky at the top of the page. I included it there immediately after I read it (see post #6 above).

CPF is moving away from the previous practice of having a long list of stickies at the head of each page - instead in most sub-forums there is now just one, which contains links to the most important and useful threads in that section.


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## mdocod (Jul 9, 2008)

LumaPower compatibility added


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## Aussie Cheese (Jul 10, 2008)

as to the e2 series of lights, 17670s work in 3 sided tubes with a SN of A2xxxxx (6 numbered SN) or Axxxxx (5 numbered SN) or less.

even with the reduced length tolerance of the AW cells, a pair in series are still about 1 mm too long for the standard e2 cell light.

i can confirm that the 

KL5A head is fully buck, and will work with 2rcrs
KL3(Gen2) head is buck/boost, and will work with 2rcrs or 17670s
KL5/KL4 is boost only and recommended running on 17670s (1.7A draw, dropping out of regulation at 2.7v) runtime in 1rcr is 18mins in regulation


----------



## mr.snakeman (Jul 13, 2008)

What about Ultralights and JETBeams and NiteCore? Great so far:twothumbs.


----------



## Evil Twin (Jul 14, 2008)

Thank you so much for putting all this great info in one place! :thumbsup:


----------



## roymail (Jul 14, 2008)

Thanks, Eric... great job!

I was needing some info about the self discharge characteristics of li-ion cells and found it easily in your post.


----------



## alfreddajero (Jul 23, 2008)

Yes it was a great read, very informative as well....learn something new everyday.


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## Rinspeed (Jul 23, 2008)

Awesome job to say the least.


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## mkphc (Jul 24, 2008)

wow!
thank you for the reference I can see that you put alot of time into this


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## Banzai (Jul 29, 2008)

Great infomation and reference... Thanks MD


----------



## LiteFan (Aug 4, 2008)

Great resource thanks


----------



## Nite (Aug 5, 2008)

*thanks AGAIN*

THATS 3 times youve helped me

First when I couldnt post, u helped me via PM (wouldve been a great thread)

then the Battery size Guide


Now the flashlight info!

this is awesome you are a Flashlight wizard on the scale of merlin or Gandalf

thanks so much


----------



## asfaltpiloot (Oct 7, 2008)

I (as a newbee to flashlights) learned a lot from this thread.
I now know what a regulated and a direct driven light is.

:thanks: for taking the time Eric.


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## Bullzeyebill (Oct 8, 2008)

Could I add some thoughts here? The KL4, KL5, and L2 use a boost regulator. Some thought that the KL5 could run with 9 volts because SF on their web site said it was ok. CM and some others have worked with the KL5 and they have found it to be boost. If the vf of the LED (Lux V) is high then 9 volts can look like it is running in buck fashion, but in actuality there is a spike at that voltage that settles down fairly fast into a flat output. My KL5, apparently having a low vf Lux V, shows a drastic rise in current as well as light output when run at 9 volts or two Li-Ions. If it was running a buck circuit there would be no drastic increase in current at 9 volts.

Also, the A2 incan bulb can run at 9 volts at the same output as two CR123's. I have done some basic runtime tests using bounce with a lightmeter to prove this. 

Bill


----------



## mdocod (Oct 8, 2008)

I think the KL4, KL5, and L2 fall into this category... 

*U2 Ultra and all other older 2xCR123 LuxV based SureFire lights*
Battery Size: 2xCR123
Regulation Type: boost (uses a LuxV emitter, which has Vf ranges ~6-7V usually)
Recommended Input Voltage Range: 3.5-6V (estimated)
Recommended Rechargeable option: 1x protected 3.7V 17670 LiCoO2
Rechargeable alternatives: 
1. 1x protected 3.7V 3.7V 18650 LiCoO2 (fits in OLDER U2s, and some with plastic sleeve that can be removed, recent U2s (last few years) have been machined from factory with tighter tolerance to CR123 size, 17670 is the only option there.
2. 2x 3.0V LiFeP04 RCR123s might work in this application, but I wouldn't recommend it.
*Some SF bodies in the older L series were so tight in the battery tube than a 14670 had to be used.

I'll update the list of lights to be more specific.


----------------------------------

[edit in] I guess it makes sense that it would tolerate 3 CR123s, the thing would run direct drive for while until the voltage from the cells dropped below the Vf of the LuxV. 

As I understand it, the LuxV is designed to be run at ~750mA at ~6-7+V depending on the specific Vf of that particular LED. It would make sense that the boost circuit probably has some inherent resistance even when it has gone passive with high input voltages, that combined with the cell resistance, and it probably never much exceeds ~1 amp across the LED, maybe a little higher..

Do you recall any specific measurements as far as how much current it ran it with 3xCR123s?


----------



## jumpstat (Oct 9, 2008)

Good Stuff Eric. Thanks..


----------



## PlayboyJoeShmoe (Nov 10, 2008)

:twothumbs:thumbsup::bow::goodjob:

I knew a lot of this battery stuff but you've opened my eyes a little wider!


----------



## GarageBoy (Nov 11, 2008)

Very nice how to!


----------



## AFAustin (Nov 12, 2008)

mdocod,

Thanks for your hard work on this---it's a great resource!

I'm hoping you come across the "final answer" as to 2xRCR123A compatibility with the L2, L4, L5, E2L, E2D LED, (modern cree/seoul versions). 

Thanks again for doing this. :twothumbs


----------



## mdocod (Nov 12, 2008)

Yea trying to track down what SF LED flashlights will work with what is practically impossible... The problem is I can only find information in bits and pieces, and often have no idea what generation of the flashlight is in question when I do find information about it, then I get information from someone about the "heads" but there is no reference about what heads went on which flashlights years ago (that I can find) so it's all incomplete data with me. I didn't follow the revisions of SF LED lights over the years so have no clue how many changes were made and when. I didn't even know till a few months ago that they actually finally updated the emitter in the U2. So this is why I have clumped together various flashlights made by SF into "chunks" of "anything with a LuxV" and then a bunch of other stuff with special footnotes etc etc... 

Eric


----------



## mdocod (Jan 14, 2009)

I have updated the guide with a blip on the new IMR cells, and finished jetbeam compatibility. I'll try to get back to the chart and add more brands in time.

Eric


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## Bolek (Feb 18, 2009)

mdocod said:


> I think the KL4, KL5, and L2 fall into this category...
> 
> *U2 Ultra and all other older 2xCR123 LuxV based SureFire lights*
> Battery Size: 2xCR123
> ...


My L2 does not light on one Li Co O2 bat but works on 2 3V regulated Li Co O2 bat. Is it safe to put two 3.7V RCR bat ?:thinking:


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## LIGHTSMAD (Apr 24, 2009)

what dedication


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## csshih (Apr 25, 2009)

I have linked countless people to this thread.. it is strange.this should be stickied.


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## DM51 (Apr 25, 2009)

csshih said:


> I have linked countless people to this thread.. it is strange.this should be stickied.


It already is. In fact it has been since it was first posted. It is in the Threads of Interest sticky at the top of the page.


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## enlighten (Jun 12, 2009)

+1 on adding Nightcore. And 4Sevens Quark


----------



## csshih (Jun 24, 2009)

DM51 said:


> It already is. In fact it has been since it was first posted. It is in the Threads of Interest sticky at the top of the page.




well.. I feel stupid again.


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## ptolemy (Aug 13, 2009)

beautiful thread 

this noob thought that 6d mag with 6x 12000 mah d cells would be 72000 mah 

not anymore!


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## flatline (Aug 13, 2009)

it could be, if you ran all six cells in parallel.


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## run4jc (Aug 28, 2009)

Geez - it is the "holy grail" of battery and flashlight compatibility information. Thank you for all this work!


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## win734440 (Jan 12, 2010)

The New NiZn Batteries seem promising. Safe, and average charge is 1.75 to 1.8 volt's and it hold's it for at lease 4 months ,so far that I have tested, Low self discharge. Thank you for all the info on the other batteries. It is very accurate,and may save someone from severe burn's,or worse.


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## Bullzeyebill (Jan 13, 2010)

win734440 said:


> The New NiZn Batteries seem promising. Safe, and average charge is 1.75 to 1.8 volt's and it hold's it for at lease 4 months ,so far that I have tested, Low self discharge. Thank you for all the info on the other batteries. It is very accurate,and may save someone from severe burn's,or worse.



Do a google search, cpf only, at the top of every CPF page, for NiZn. Some info here, though not a lot. Going to take a while for it to catch on, and we are interested in real world capacity, discharge rates, and ability to hold charge over time. So far we are seeing Eneloops, and some other LSD's, as the best bet, in the AA format.

Bill


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## win734440 (Feb 8, 2010)

Has anyone experimented with the NiZn batteries yet ? they have more voltage then NiMH a single 
AA is around 1.8 volts fresh out of the charger and it holds the charge for up to 6 months that i have seen so far. other then knowing that they work well,that's it I have not studied them any futher. Looking forward to reading what you have to say about them if and when you test them. Thank you, for the above info


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## mdocod (Feb 8, 2010)

Only thing I know about the NiZn cells at this time is what little I have read along the lines of short term experience here on this forum. Not a ton of buz about them so far.


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## Justin Case (Feb 9, 2010)

FYI, the old KL4 head I mod'ed used an LTC1872 boost IC, which has an absolute max voltage input spec of 10V. No guarantees that any of the other components on the driver can also take 10V, though. For two different KL4s, I measured drive currents of 630mA and 665mA.

In my U2A XP-G mod thread, I have some shots of the buck driver ICs. The challenge is identifying them. So far, I have been only partially unsuccessful. I've IDed the Allegro A1104 Hall effect sensors and the ATMEL 16F690 controller. For the stock U2A, I measured 4.5V min to run in full regulation. Thus, 1xLi-ion is going to be a little low for input voltage and you are not going to get full lumens output.


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## BruceWillEs (Jun 9, 2010)

You should add an advantage of NICD cells:

"Can be stored when discharged. (They don't get damaged like NIMHs, when stored in a discharged state)"

This is an advantage of NICDs that only very few people know.


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## BMart (Aug 25, 2011)

Where do you find the input voltage and regulator information? I'm compiling a similar "battery compatibility" list in a Google Spreadsheet and that information would be useful. Let me know if you want access to the spreadsheet.


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## Sam Z (Oct 29, 2012)

tagged for reference

Thank you for the helpful guide


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## TravisLight (Dec 13, 2012)

OMG, this is the greatest thread ever!!


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## xZenTigerx (Jul 16, 2013)

Wow lots of info put forth in a very readable format with excellent explanations!
Thanks I learned some more about LEDs and Flashlights.


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## QuantumSam (Aug 17, 2015)

I just bought a Sunwayman C22C flashlight - how do I chose a battery? Do I go for the highest capacity I can afford and what about voltage? Should I get 3.6,3.8,4.2?


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## Bullzeyebill (Aug 20, 2015)

QuantumSam said:


> I just bought a Sunwayman C22C flashlight - how do I chose a battery? Do I go for the highest capacity I can afford and what about voltage? Should I get 3.6,3.8,4.2?



Your question is best asked in the LED Flashlights forum. 

Bill


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## Blackjack_21 (Oct 16, 2017)

Hate to beat dead horses, but I've got the older E2D LED Defender (200 lumens in high-beam), an I wonder if the info for the Cree/Seoul version is compatible with this older light. If not, any advice?


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