Flashlight Batteries and Bulbs - John Dunn, Consultant, Ambertec, P.E., P.C.

It's a small thing perhaps that so many flashlights become unreliable with use, but it's been a pet peeve of mine for quite some time.

Many flashlights depend on the tip of the bulb to make contact with the positive end of the upper flashlight cell as sketched below on the left. This works okay for a while, but eventually, the metal of the bulb's tip deforms by flattening out while the positive tip of the flashlight cell also deforms by becoming concave as sketched below on the right.

Then the flashlight doesn't stay lit as I hold it. I have to shake a little it to get light or I have to twist the light bezel back and forth a little bit.

I'm sure you know the drill.    

 

When this happens, I can put a wad of aluminum foil between the bulb tip and the positive tip of the flashlight cell to make things okay again, but I really resent that I need to do that.

These days therefore, if I buy a flashlight, I look for one that has the bulb encased a protective housing with a brass tab for contacting the upper flashlight cell. Nothing deforms.

Of course, as you might guess, one of those "better" flashlights that I bought now has an intermittent sliding switch.

Edsel Murphy lives!

Comments

[george storm]

Edsel? Presumably attached at a late stage in the game because of a certain Ford?

[Mark Walter]

It is a classic example between cost and reliability. It's cheaper to use the solder seal to make contact with the batteries: probably save $0.05 vs having a brass tab. But people want $2 flashlight so they sell. There are high end flashlights available: aluminum housing vs plastic, watertight with o-ring seals etc, so those who want a more reliable product (policemen, servicemen and the like) buy those.

The free market is a good thing: you can buy lower priced product or spend more for a better made/designed product. Our choice.

[John Dunn]

The frustrating thing is that every time I go looking for a flashlight, all I see is the cheap junk. If the better made ones were there, I would buy those but I guess most people would buy the cheaper ones.

The flashlight cells are junk too. Their soft metal tips deform inward and cause problems.

[Larry Rachman]

The price of LED flashlights has dropped to the point where the classic PR2 bulb will soon be seen only in the Smithsonian. And good riddance, too, those things were one of the more miserable recollections of my youth.

There are a lot of bad, inexpensive LED flashlights out there. At the other end of the spectrum, Fenix (www.fenixlight.com) makes some very nice ones. But there's definitely some sticker shock to be had at the high end. You don't *have* to spend more than $100 to own one of their products, but its quite possible.

but here is a link for some very nice one.