After reading all the crap about the new photon III's, I was just wondering about the reliability of the circuits used in some of these LED lights. One of the main appeals of LED's is their robustness, they're practically indestructible, but at the expense of brightness. It wouldn't really make sense to have a nice indestructible LED light and have the circuit go out instead of the bulb. I'd much rather have to change a bulb once in a while then to throw away a light because I couldn't change the circuit. Does anyone have any evidence that these circuits are just as reliable as the LED's? I guess this is a question more for Gransee, but do any of the lights go through some sort of shock or vibration testing or are the circuits protected from vibration somehow? Maybe potted in silicone or something? I'd like to get a nice voltage regulated light like the ARC, but I really like the simplicity of my Photon II, just a battery and LED.
Circuit reliability
- Thread starter InTheDark
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Gransee
Flashlight Enthusiast
Great question "InTheDark". A similar question was just asked over in the incandescent forum. It would be nice to hear from the reviewers on this one since they are probably less biased than I am. That being said, here are my thoughts.
Even though electronic circuits can last a lifetime, putting them in a handheld product does subject them to vibration, moisture, corrosion, etc.
Flashlights also add the problem of the battery wanting to otherwise destroy the innards through corrosion or other devious means.
I don't know the deal with the photon 3 since I have never looked at one. It may be something as simple as stray capacitance, static electricity of the user, or dirty switch contacts. Certainly adding to the complexity of a flashlight can increase the likelihood of something failing- leaving you er.. In the dark.
But even a simple but bad design can let you down compared to a complex but good design. I think all of us have had a simple; "batteries in a tube with a bulb" fail on us one time or another. Not that that such a concept is a bad design; you just need to study each implementation. So choose your lights wisely and if that fails, simply carrying a spare can safe your life.
With all that understood, what about lights that have a dc-to-dc inverter/regulator? The core circuit itself should be fine for many years. These types of circuits tend to be less picky of things like static electricity, stray capacitance, etc. And since no push buttons are involved, you have one less thing to go wrong. We also pot the circuit and the base of the LED in a hard, glass-like resin. This increases shock resistance and further protects the circuit from moisture in the event the o-ring failed.
But they can still fail. And if they do, your out of luck. When estimating the reliability of a flashlight the characteristics of the least reliable component is the usally the game killer. This is best refered to as the "weakest link". You also get a compounded risk from the remaining components. Although each is more reliable than the weakest link, together they increase the odds of a failure. This being said, some would think the best light to buy would be a "tube, bulb and a battery". But we are not looking at the whole picture yet- another factor that you must include is the reliability of the bulb itself. Will it survive the shock of a fall? At what inopportune time will it just burn out from old age? 30 hours is old age for some bulbs! Battery life and how much warning you have of a battery failure is also a factor. Although just having some light is most important, how bright it is during its entire runtime is still another important factor.
So it is a little more complicated than it first appears.
Another problem I haven't seen discussed here that is unique to flashlights that have a PCB interfacing with the battery. Our flashlights use PCBs (PC boards). Even some lights with just a resistor in them can use a PCB. The problem occurs when what I call, "projectile battery phenomena" caused by impacting the light violently, forcing the top cell into the PCB, cracking it or knocking parts off the other side. This was something that we where very worried about with the early prototypes and extensively tested for. We severely reduced the risk by using a board with a small thickness to diameter ratio. For example, our PCB is three times the thickness of the board in the Infinity while being less than half the diameter. The potting resin that encases the electronics also limits the flex of the board by not giving it anyplace to go without compressing the whole hard resin slug. Furthermore, we also apply a 'foam' battery retainer that absorbs a large percentage of shock before is even gets to the PCB. This is all well and good but the proof is in the real life statistics: the Arc survives impacts quite well.
Now such a light still has to deal with the problems that all lights have to deal with, batteries and problems with dirty contacts to those batteries. That is the number one thing that kills our lights: battery corrosion fouling the contacts. We use corrosion resistance metals, but they still won't conduct very well if coated in a goop deposited by something else corroding.
One thing nice about Lithiums is that they are less likely to corrode the interior of your nice light. They have other advantages as well but the trade off is you typically get less light per dollar compared to a good alkaline. With the Arc-LS (shameless plug) you can choose either lithium or alkaline-whichever suits you better.
So you see that some complexity can be a good thing as long as it is applied correctly. But simple problems can cause any light to fail.
Peter Gransee
Even though electronic circuits can last a lifetime, putting them in a handheld product does subject them to vibration, moisture, corrosion, etc.
Flashlights also add the problem of the battery wanting to otherwise destroy the innards through corrosion or other devious means.
I don't know the deal with the photon 3 since I have never looked at one. It may be something as simple as stray capacitance, static electricity of the user, or dirty switch contacts. Certainly adding to the complexity of a flashlight can increase the likelihood of something failing- leaving you er.. In the dark.
But even a simple but bad design can let you down compared to a complex but good design. I think all of us have had a simple; "batteries in a tube with a bulb" fail on us one time or another. Not that that such a concept is a bad design; you just need to study each implementation. So choose your lights wisely and if that fails, simply carrying a spare can safe your life.
With all that understood, what about lights that have a dc-to-dc inverter/regulator? The core circuit itself should be fine for many years. These types of circuits tend to be less picky of things like static electricity, stray capacitance, etc. And since no push buttons are involved, you have one less thing to go wrong. We also pot the circuit and the base of the LED in a hard, glass-like resin. This increases shock resistance and further protects the circuit from moisture in the event the o-ring failed.
But they can still fail. And if they do, your out of luck. When estimating the reliability of a flashlight the characteristics of the least reliable component is the usally the game killer. This is best refered to as the "weakest link". You also get a compounded risk from the remaining components. Although each is more reliable than the weakest link, together they increase the odds of a failure. This being said, some would think the best light to buy would be a "tube, bulb and a battery". But we are not looking at the whole picture yet- another factor that you must include is the reliability of the bulb itself. Will it survive the shock of a fall? At what inopportune time will it just burn out from old age? 30 hours is old age for some bulbs! Battery life and how much warning you have of a battery failure is also a factor. Although just having some light is most important, how bright it is during its entire runtime is still another important factor.
So it is a little more complicated than it first appears.
Another problem I haven't seen discussed here that is unique to flashlights that have a PCB interfacing with the battery. Our flashlights use PCBs (PC boards). Even some lights with just a resistor in them can use a PCB. The problem occurs when what I call, "projectile battery phenomena" caused by impacting the light violently, forcing the top cell into the PCB, cracking it or knocking parts off the other side. This was something that we where very worried about with the early prototypes and extensively tested for. We severely reduced the risk by using a board with a small thickness to diameter ratio. For example, our PCB is three times the thickness of the board in the Infinity while being less than half the diameter. The potting resin that encases the electronics also limits the flex of the board by not giving it anyplace to go without compressing the whole hard resin slug. Furthermore, we also apply a 'foam' battery retainer that absorbs a large percentage of shock before is even gets to the PCB. This is all well and good but the proof is in the real life statistics: the Arc survives impacts quite well.
Now such a light still has to deal with the problems that all lights have to deal with, batteries and problems with dirty contacts to those batteries. That is the number one thing that kills our lights: battery corrosion fouling the contacts. We use corrosion resistance metals, but they still won't conduct very well if coated in a goop deposited by something else corroding.
One thing nice about Lithiums is that they are less likely to corrode the interior of your nice light. They have other advantages as well but the trade off is you typically get less light per dollar compared to a good alkaline. With the Arc-LS (shameless plug) you can choose either lithium or alkaline-whichever suits you better.
So you see that some complexity can be a good thing as long as it is applied correctly. But simple problems can cause any light to fail.
Peter Gransee
Part of the issue is probably to determine if the device was designed to be reliable in the first place.
You can see in Peter's post they have put a lot of consideration into reliability.
I would also be willing to bet that not many Actionlights fail easily and they have all sorts of complicated modes (at least in V2).
On the other hand, I bet making the Photon III bulletproof wasn't part of the design consideration.
Also note that most LED lights don't currently have that many electronics, if any.
-john
You can see in Peter's post they have put a lot of consideration into reliability.
I would also be willing to bet that not many Actionlights fail easily and they have all sorts of complicated modes (at least in V2).
On the other hand, I bet making the Photon III bulletproof wasn't part of the design consideration.
Also note that most LED lights don't currently have that many electronics, if any.
-john
