Yesterday, I dropped my "Hard-Case" LED torch on the wooden deck outside my house. It went out, and wouldn't turn on again. This surprised me, because the torch is rebustly made, and LEDs aren't that fragile.
On a hunch, I replaced the batteries. It works fine.
Further experiment showed that one of the previous batteries, and Energise Alkaline, had died. It's capable of delivering only a few microamps, and has an EMF of about 0.5V.
I've never heard of a dry cell failing like that.
Sylvia.
Alkaline cells are encased in a sleeve that reverses their polarity -- the center electrode would otherwise be negative. It's possible that the sleeve was damaged or knocked loose.
Well, I suppose some may be constructed that way. Close examination of the failed one shows that the positive button is just an extension of the external casing, and the negative is a separate area insulated from it. That is, much like a zink-carbon battery in reverse.
Sylvia.
In message , Sylvia Else writes
Last time I ripped an alkaline cell apart (a *long* time ago) the negative terminal was attached to a long thin spike pushed down the centre of the cell, it's possible I suppose that an impact may have broken this close to the terminal or it may have pierced an insulator or seal inside the cell.
BTW, I'd not describe an alkaline cell as 'dry', to my mind that suggests a zinc carbon cell.
-- Clint Sharp
That`s one of the reasons professionals almost always use Duracells in radio microphone packs. It`s not uncommon to find an energiser battery which gives no voltage unless you press on the end terminals. In the Duracell 9volt 'PP3' the connecting strips between cells are spot welded, in many other makes they rely on contact pressure alone to make a good connection with inconsistant results, especialy under heavy load.
Only yesterday I pulled apart a Panasonic PP3 which had failed prematurely, to find that the positive contact made it`s only connection to the stack by having sharp 'points' which are intended to pierce the soft plastic covering of the cells. Pressing down on the battery connector would make the voltage come and go.
Duracell PP3's are a handy source of sub AAA cells btw.
Ron
It's dry in the sense that the electrolyte doesn't slosh around (as it does in a lead-acid storage battery).
I've never had any cell, from any manufacturer, fail in that way (that I was aware of).
On the other hand, I've had Duracells leak and damage the equipment they were in. In one case I was able to clean up the mess. In the other case, Mallory * was obliged to replace part of the device (an Olympus dictating machine).
I've never had an Eveready * or Toshiba leak. I don't use Duracells.
I just realized the OP was talking about batteries, not cells. Nevertheless...
I used the word loosely. They were in fact cells.
Sylvia.
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