Sceadwian said:Virtual every LED torch on the market works the same way
Sceadwain said:BrownOut. I have personally taken apart hundreds of flashlights and have never once seen anything like a joule thief, and never a boost converter for that matter,
there's a good reason for this because the best of the best modern day boost converters in most situations are in the range of 75-85% efficient
some specific designs can hit the 90's but as complexity and efficiency goes up so does cost
The answer to something like a Joule thief in a flashlight is simple... use a bigger battery
I can find no net benefit to the use of a Joule thief or boost converter in a commerical flashlight
it's easier to get as close as you can to it's nominal operating voltage and in the case of an LED you use as low a value current limit resistor as possible to prevent failure
ok just ignore me then and carry on with the willy waveing!!
I'm sorry BrownOut, but I can no longer consider you as someone that knows what they're talking about on this subject as I happen to actually have half a dozen white LED keyfobs left (the rest I give to friends) that use 2016 or 2032 Lithium cells for power with no current limit resistor (cell resistance only) Life span is probably only a few hours with constant use, but the Lithium chemistry is low self discharge so they last as long as the self discharge of the battery otherwise, which is 10 years.Even a single LI cell wouldn't be enough to light the white 3.6V LED
This is a flash light not a camp light it's function is not for bulk light it is for getting around by flashing light, a camp light should be more specifically defined as something that is used long term to illuminate your immediate surrounding (the camping area) be it a tent for a smaller unit or a 20x20 area in the case of a propane lantern..I go camping at least 4 times a year, and depend on the light to move around in the darkness.
Schedwian said:I'm sorry BrownOut, but I can no longer consider you as someone that knows what they're talking about on this subject as I happen to actually have half a dozen white LED keyfobs left (the rest I give to friends) that use 2016 or 2032 Lithium cells for power with no current limit resistor (cell resistance only) Life span is probably only a few hours with constant use, but the Lithium chemistry is low self discharge so they last as long as the self discharge of the battery otherwise, which is 10 years.
This is a flash light not a camp light it's function is not for bulk light it is for getting around by flashing light, a camp light should be more specifically defined as something that is used long term to illuminate your immediate surrounding (the camping area) be it a tent for a smaller unit or a 20x20 area in the case of a propane lantern..
because it will last longer than it's practically needed, and you could have done the smart thing which is simply not use a booster converter at all and a AA Lithium primary which will last you to the practical self discharge of the cell in your circumstances.
You have to be critical of your own design, there are always more than one version of a device that needs to be made. The 2032 powered keyfobs are my personal favorite, it's simply put impossible to beat the price/size/performance/practical useability
I would like to actually know what you're using for your camp light though the maker and model of the unit so that I can look into it a little further and not comment without knowing what you're actually using.
Someone already has. When I showed a friend my (homemade) Joule thief 1.5V-cell flashlight, he showed me his (smaller, takes an AAA cell). Basically the same thing, except that his uses a piece of silicon (an ASIC) instead of my primitive 1-transistor blocking oscillator. Probably as efficient or more so.
By the way, I notice you neatly sidestepped my questions about your mega-flashlight. How long can that thing run? Does it actually use AAAs (looks more like AAs)? (I guess they are AAAs, since you said you're using 4 of them.)
79% W/O Cap. 91% with it.
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