new hamfest finds

From: Don Maslin <donm_at_cts.com>
Date: Sun Jun 6 18:14:34 2004

On Sun, 6 Jun 2004, Joe R. wrote:

> At 12:11 PM 6/6/04 +0100, you wrote:
> >On Jun 5, 21:28, William Donzelli wrote:
> >
> >> Most of these batteries were made in World War 2, many by a company
> >called
> >> Willard. They pretty much fell out of fashion roight after the war in
> >new
> >> designs, but probably were still produced for all of the existing
> >radios
> >> (mainly) that used them.
> >
> >Actually, small transparent lead-acid batteries (usually with the three
> >balls in a column) were still made up to the 1980s. Professional
> >flashguns and some "portable" phones used them.
>
> I just looked at my battery aggain and sure enough it has the three
> columns in the back of it with the balls inside. I didn't notice that
> before. I don't think I've ever seen a battery with them built in. Usually
> we used a Hydrometer to suck out part of the electrolyte and test it. It's
> a large syringe with a clear plastic or glass tube in it and has 3, 5 or 7
> balls inside the tube. The ratio of sulphuric acid to water in the
> electrolyte changes depending on the state of charge of the battery. As the
> acid/water ratio changes the specific gravilty of the solution also
> changes. The different balls in the hydrometer have different specific
> gravities so more of them will float when the charge is higher and there is
> more acid in the solution. Most LA batteries sold in this country in the
> past 25 years are now sealed and are SUPPOSED to be maintenance free so
> very few people know how to check one any more.
>
> Joe

You were using one of the modern ones, Joe. My introduction to
battery hydrometers was the syringe as you describe, but with a
single calibrated glass float whose position relative to the top
of the fluid introduced into the syringe told the story.

                                                - don
Received on Sun Jun 06 2004 - 18:14:34 BST