foxyrick
British Pork
- Joined
- Dec 26, 2006
- Messages
- 2,254
Flashlights have been mentioned a couple of times recently, along with what cells to use. I've looked into this myself, so here's a few tips if you're thinking of getting one. I won't get into recommending actual models though, because it changes rapidly and I'm not that current with what's out there right now.
Why LED's?
LED's offer much longer run times on a set of cells than incandescent bulbs. They are bright enough for most purposes and can frequently be dimmed to lengthen cell life. They are not susceptible to being damaged if dropped. They last much longer than a bulb. On the negative, they aren't as good for colour rendition than a good incandescent, but they are improving and it's certainly good enough for me.
Some good makes are Surefire, Fenix, Jetbeam, Olight, Tiablo, Inova, plus several others I can't think of right now.
Note well: Make sure you put the cells in the correct way round. LED's and their driver circuits will be damaged otherwise.
For me, flashlights fall into two main categories: ones for frequent use and ones for BOB's and survival kits.
The category determines the type of cells that are best, that then determines what flashlight to get to take those cells.
Cell Choice
For frequent-use flashlights (like the Jetbeam I carry in my BOE/Workbag) you don't want it to cost too much to run. Long term storage of cells is not an issue. This leads to rechargeable cells being best. You have the choice of lithium ion or NiCD/NiMH. NiMH is better than NiCD, but lithium ion (or lithium polymer) is much better still (much more power). Note that all rechargeable cells self-discharge, so don't expect them to work if they were last charged three months ago. They need topping up occasionally.
If you want to store your flashlight (or just cells) for when it's needed, you should use primary (=non-rechargeable) lithium cells. These can be either the common CR123 cells, or 1.5V AA-sized primary lithium cells. Make sure you get AA lithium cells intended for things like cameras or MP3 players. These have a shelf life of ten years, much longer than alkaline cells.
So, what size cells to choose? For frequent-use, you could choose any size really. My Tiable A8 runs on 18650 size Lithium ion cells (18650=18mm diameter, 65mm long) which hold plenty of power. Long-term storage is limited to CR123 and AA as these are the only ones with a 10-year shelf life.
There is a lot to be said though for a flashlight that can take a range of sizes, especially if that includes AA. My Jetbean MkII-X will take one AA-sized cell. It can use a 14500 size lithium ion rechargeable cell, NiCD, NiMH, non-rechargeable 1.5V lithium cells and standard 1.5V alkalines. So it covers all the bases really, from daily use to long-term storage and easy resupply. It's also stupidly bright, especially on the 14500.
Another point on rechargeable lithium ion cells: they give 4.2V when freshly charged. Some lights are designed fro primary lithium cells which are 3.6V and can be killed by 4.2V. Others can take it but you might lose some life in the LED - often these will be brighter on 4.2V. Still others are fine, like my Jetbeam. You can also get 3.6V rechargeables now, but make sure to get a matching charger.
LED Brightness and Colour
Get the brightest rated LED you can afford. LED's come in different grades due to the manufacturing process being highly variable. They get tested and 'binned' accordingly. Basically, a better brightness or efficiency grade or 'bin' will give more light at the same power use, or the same light at a lower power giving a longer run time. They are also binned according to colour variation. This is less commonly advertised than brightness bins and you won't know what you are getting unless you buy from a flashaholic. Most are good enough these days though.
LED brightness is generally measured in lumens. The more, the better. Be aware that some sellers will tell you the lumen output at the emitter, not what actually comes out of the lens which will be less. Also be aware that some flashlights are described by a power use (3 Watt, 5 Watt etc.) This doesn't necessarily mean much - a good 3W could give more light than a poor 5W! But the 5W will definitely eat your cells faster. Look for the lumen rating.
There are two main contenders in LED's: Luxeon and Cree. Cree-based flashlights usually state the LED brightness grade. Q5 is still the highest generally available I believe, but lower grades (Q4 for example) are still sold. With Luxeon-based ones you often aren't told the bin grade. A more recent Luxeon LED is the Rebel, which seems to be a very good LED indeed.
I don't have a Rebel-based light, but from what I have read and seen, it produce a slightly warmer light than the Crees (which are a little cold or bluish), giving better colour rendition in the outdoors, but are just very slightly dimmer at the same power usage than the Q5 Crees. Probably not enough difference to really matter.
Output Pattern
Then there is the issue of flood versus throw. This is determined by the lens and/or reflector as well as the LED. For survival-type use, I think flood is more important. Most often there is still a hotspot in the centre that gives some throw, with a good flood (or spill) around it. But if you intend surviving in a desert, maybe you need a thrower. More throw requires larger reflectors or more expensive optics though.
Other Modes
Multiple output levels are really useful. Most of the time you don't need full output on a modern LED light. In fact, it can be way too bright. Lowering the output makes your cells last longer. Some can last days on the lowest setting.
Other output modes often seen are strobe and SOS. Personally, I quite like having them on a survival light - you never know when it might come in handy. It often makes the light harder to use though as there are more modes to switch through, on a single button, to get to the one you want. Some folks really dislike these extra functions and for an everyday work light, I tend to agree.
Some models will remember the last setting you used next time you turn them on. Some will always start in one particular mode. Take you choice.
Switches
Switches can be on the side, a 'twisty' where you rotate part of the body or cap, tail clicky where you push a button in the end, and reverse-clicky where the light turns on when you release the tail button, rather than when you depress it - that makes a difference if you try to signal with it. Tail clickies are often seen as more tactical than any other type, especially if the light turns on at full brightness to blind an attacker.
I'm getting tired now, so I'll leave it there except for one more thing:
Lithium Ion safety
Unprotected lithium ion cells (the rechargeable ones) have been known to explode violently. It's often called 'venting with flame' and resembles a roman candle! Seriously, they are really nasty if they go off. There have been cases of cells bursting the aluminium flashlight bodies.
What do I mean by unprotected? Well, normal consumer lithium ion cells have a protection circuit built into them that breaks the current flow if: the cell is discharged too much and then recharged, the cell is overcharged, the cell is reverse charged, the cell is overloaded, or the cell just gets upset over something.
However, it is easy to buy unprotected lithium ion cells over the 'net from many suppliers. They give a little more available power and are less bulky than protected cells. So many people (including me) use them.
So be aware, if you use unprotected cells:
1. Never discharge them fully (turn off the flashlight when it starts dimming). Over-discharging kills them anyway, so you don't want to do it. If you do (for instance it's an emergency and you need to use every last drop of light), DO NOT try to recharge them. Throw them away.
2. Make sure the charger is matched to the cells. Generally the charging current does not matter when charging lithium ions, but the charging voltage does. If you get 3.6V rechargeable cells, get a charger for 3.6V, not 4.2V.
3. Never mix different types, makes or ages of cells in a light that takes more than one cell. This is seriously dodgy.
4. For a multicell light, make sure the cells are charged equally before putting them together. Some people even check the cell voltage with a voltmeter and match their cells together that way.
5. Never short circuit the cell. Make sure they can't be shorted accidentally while in storage. I put a piece of tape around the ends.
6. Make sure the flashlight can't be turned on accidentally. You don't want this anyway.
7. Never leave the cells charging unattended, especially if using a cheap, 'nano'-type charger that doesn't have as much protection circuitry as the more expensive ones.
8. Don't puncture the cell. This is the quickest way to turn it into a firework.
Hope folks find some of this useful. Please ask questions about all the stuff I'm sure to have missed.
Why LED's?
LED's offer much longer run times on a set of cells than incandescent bulbs. They are bright enough for most purposes and can frequently be dimmed to lengthen cell life. They are not susceptible to being damaged if dropped. They last much longer than a bulb. On the negative, they aren't as good for colour rendition than a good incandescent, but they are improving and it's certainly good enough for me.
Some good makes are Surefire, Fenix, Jetbeam, Olight, Tiablo, Inova, plus several others I can't think of right now.
Note well: Make sure you put the cells in the correct way round. LED's and their driver circuits will be damaged otherwise.
For me, flashlights fall into two main categories: ones for frequent use and ones for BOB's and survival kits.
The category determines the type of cells that are best, that then determines what flashlight to get to take those cells.
Cell Choice
For frequent-use flashlights (like the Jetbeam I carry in my BOE/Workbag) you don't want it to cost too much to run. Long term storage of cells is not an issue. This leads to rechargeable cells being best. You have the choice of lithium ion or NiCD/NiMH. NiMH is better than NiCD, but lithium ion (or lithium polymer) is much better still (much more power). Note that all rechargeable cells self-discharge, so don't expect them to work if they were last charged three months ago. They need topping up occasionally.
If you want to store your flashlight (or just cells) for when it's needed, you should use primary (=non-rechargeable) lithium cells. These can be either the common CR123 cells, or 1.5V AA-sized primary lithium cells. Make sure you get AA lithium cells intended for things like cameras or MP3 players. These have a shelf life of ten years, much longer than alkaline cells.
So, what size cells to choose? For frequent-use, you could choose any size really. My Tiable A8 runs on 18650 size Lithium ion cells (18650=18mm diameter, 65mm long) which hold plenty of power. Long-term storage is limited to CR123 and AA as these are the only ones with a 10-year shelf life.
There is a lot to be said though for a flashlight that can take a range of sizes, especially if that includes AA. My Jetbean MkII-X will take one AA-sized cell. It can use a 14500 size lithium ion rechargeable cell, NiCD, NiMH, non-rechargeable 1.5V lithium cells and standard 1.5V alkalines. So it covers all the bases really, from daily use to long-term storage and easy resupply. It's also stupidly bright, especially on the 14500.
Another point on rechargeable lithium ion cells: they give 4.2V when freshly charged. Some lights are designed fro primary lithium cells which are 3.6V and can be killed by 4.2V. Others can take it but you might lose some life in the LED - often these will be brighter on 4.2V. Still others are fine, like my Jetbeam. You can also get 3.6V rechargeables now, but make sure to get a matching charger.
LED Brightness and Colour
Get the brightest rated LED you can afford. LED's come in different grades due to the manufacturing process being highly variable. They get tested and 'binned' accordingly. Basically, a better brightness or efficiency grade or 'bin' will give more light at the same power use, or the same light at a lower power giving a longer run time. They are also binned according to colour variation. This is less commonly advertised than brightness bins and you won't know what you are getting unless you buy from a flashaholic. Most are good enough these days though.
LED brightness is generally measured in lumens. The more, the better. Be aware that some sellers will tell you the lumen output at the emitter, not what actually comes out of the lens which will be less. Also be aware that some flashlights are described by a power use (3 Watt, 5 Watt etc.) This doesn't necessarily mean much - a good 3W could give more light than a poor 5W! But the 5W will definitely eat your cells faster. Look for the lumen rating.
There are two main contenders in LED's: Luxeon and Cree. Cree-based flashlights usually state the LED brightness grade. Q5 is still the highest generally available I believe, but lower grades (Q4 for example) are still sold. With Luxeon-based ones you often aren't told the bin grade. A more recent Luxeon LED is the Rebel, which seems to be a very good LED indeed.
I don't have a Rebel-based light, but from what I have read and seen, it produce a slightly warmer light than the Crees (which are a little cold or bluish), giving better colour rendition in the outdoors, but are just very slightly dimmer at the same power usage than the Q5 Crees. Probably not enough difference to really matter.
Output Pattern
Then there is the issue of flood versus throw. This is determined by the lens and/or reflector as well as the LED. For survival-type use, I think flood is more important. Most often there is still a hotspot in the centre that gives some throw, with a good flood (or spill) around it. But if you intend surviving in a desert, maybe you need a thrower. More throw requires larger reflectors or more expensive optics though.
Other Modes
Multiple output levels are really useful. Most of the time you don't need full output on a modern LED light. In fact, it can be way too bright. Lowering the output makes your cells last longer. Some can last days on the lowest setting.
Other output modes often seen are strobe and SOS. Personally, I quite like having them on a survival light - you never know when it might come in handy. It often makes the light harder to use though as there are more modes to switch through, on a single button, to get to the one you want. Some folks really dislike these extra functions and for an everyday work light, I tend to agree.
Some models will remember the last setting you used next time you turn them on. Some will always start in one particular mode. Take you choice.
Switches
Switches can be on the side, a 'twisty' where you rotate part of the body or cap, tail clicky where you push a button in the end, and reverse-clicky where the light turns on when you release the tail button, rather than when you depress it - that makes a difference if you try to signal with it. Tail clickies are often seen as more tactical than any other type, especially if the light turns on at full brightness to blind an attacker.
I'm getting tired now, so I'll leave it there except for one more thing:
Lithium Ion safety
Unprotected lithium ion cells (the rechargeable ones) have been known to explode violently. It's often called 'venting with flame' and resembles a roman candle! Seriously, they are really nasty if they go off. There have been cases of cells bursting the aluminium flashlight bodies.
What do I mean by unprotected? Well, normal consumer lithium ion cells have a protection circuit built into them that breaks the current flow if: the cell is discharged too much and then recharged, the cell is overcharged, the cell is reverse charged, the cell is overloaded, or the cell just gets upset over something.
However, it is easy to buy unprotected lithium ion cells over the 'net from many suppliers. They give a little more available power and are less bulky than protected cells. So many people (including me) use them.
So be aware, if you use unprotected cells:
1. Never discharge them fully (turn off the flashlight when it starts dimming). Over-discharging kills them anyway, so you don't want to do it. If you do (for instance it's an emergency and you need to use every last drop of light), DO NOT try to recharge them. Throw them away.
2. Make sure the charger is matched to the cells. Generally the charging current does not matter when charging lithium ions, but the charging voltage does. If you get 3.6V rechargeable cells, get a charger for 3.6V, not 4.2V.
3. Never mix different types, makes or ages of cells in a light that takes more than one cell. This is seriously dodgy.
4. For a multicell light, make sure the cells are charged equally before putting them together. Some people even check the cell voltage with a voltmeter and match their cells together that way.
5. Never short circuit the cell. Make sure they can't be shorted accidentally while in storage. I put a piece of tape around the ends.
6. Make sure the flashlight can't be turned on accidentally. You don't want this anyway.
7. Never leave the cells charging unattended, especially if using a cheap, 'nano'-type charger that doesn't have as much protection circuitry as the more expensive ones.
8. Don't puncture the cell. This is the quickest way to turn it into a firework.
Hope folks find some of this useful. Please ask questions about all the stuff I'm sure to have missed.
)! Good point on the output levels...you don't need 300+ lumen everytime you turn your flashlight on! It's nice to have when you need it, but 90% of your utility uses will be much lower on the lumen-ouput and also give you longer output life.
