Path: utzoo!attcan!uunet!portal!cup.portal.com!mmm
From: mmm@cup.portal.com (Mark Robert Thorson)
Newsgroups: sci.electronics
Subject: Re: HV Cap Fun! (Fun with Batteries)
Message-ID: <19591@cup.portal.com>
Date: 18 Jun 89 00:57:05 GMT
References: <4924@m2c.M2C.ORG> <3806@mit-amt> <20772@quacky.mips.COM>  <27119@pbhya.PacBell.COM> <4489@midas.STS.TEK.COM> <397@richsun.UUCP>
Organization: The Portal System (TM)
Lines: 18

When I was a kid, I was given a rechargable flashlight that didn't work
anymore.  It was a crude affair on the inside, just a bridge rectifier, a cap,
and a current-limiting resistor to trickle charge the batteries (no step-
down transformer, just the resistor).

I wired these components into a cardboard box with a set of Fahrenstock clips
bolted to the top.  Now I have a crude^squared battery charger.  I also had
two batteries, which I wedged in the clips so they could charge while
I was at school.  When I came home, one of the batteries was in pieces on the
floor, which seemed odd.  I assumed it fell off the table, but I didn't yet
realize why the cap and some of the innards had come off the case.

The other battery didn't seem to have any charge on it, so I took it to the
garage to open it up and see how it was put together.  By the way, the case of
this other battery was bulging, but for some reason that didn't register in
my mind.  I put the battery on one of the concrete steps of the garage and
hit it with a hammer.  I have never heard such a loud bang as the one that
battery made.  My ears were still ringing the next day.