LED Flashlights

Three alkaline cells, each containing a nickel-plated cap pressed against the (-) electrode, in weak-spring battery connector, which connector is pressed weakly to the LED leads on one end, and to a switch on the other, and the switch applies weak pressure to its contacts to turn ON, and the contact leaf presses the aluminum endcap, which threads into the aluminum barrel, which in turn presses against the LED wires.

I count fifteen places where metal/metal contact can have a speck of lint or fingerprint that impedes conduction. Eighteen if three coil springs in the battery clip just press against the leaf of metal leading to the next cell.

A connectorized welded-cell battery pack (like in most old cordless phones), and soldered termination of the LEDs, and solid-state or sealed (reed switch?) ON/OFF switching, would make it as reliable as my Sonicare toothbrush.

cheap?

When LED flashlights first became available, I bought a Duracell commonly used handheld (5" long" flashlight for about $30. It still has the irregularity.

Take a cheap one apart. Besides the battery contact issue someone mentions, they may be relying on good contact through the cap, and maybe worse, the cheap ones are either badly soldered or are put together so pressure is all that holds the LED leads in place.

I'd also point out that the cheap ones depend on a bunch of LEDs to provide the light, sometimes that's the selling point, but since they are using cheap LEDs and barely soldering them together, it's not uncommon to find completely dead LEDs in some of the cheap ones. I'm not sure if they are dead or just bad connections that dont' reconnect with a jarring of the flashlight.

Someone gave me a sort of "trouble light" that used Cree LEDs, just a few. That thing is very different, tiny little chips that light up bright, compared to many of the LED flashlights that use a bunch of epoxy cased LEDs. That thing is a lot more trustworthy than the cheap LED troublelight I'd prevously bought.

But, the thing runs off three AA or AAA batteries (I can't remember) and there's some constant drain on those batteries. So it's not safe to leave the batteries in, they may not be working when you need the light.

Michael

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same problem as regular flashlights. non-conductive patina on the contacts