6 Jun
2004
6 Jun
'04
1:41 a.m.
At 12:11 PM 6/6/04 +0100, you wrote:
On Jun 5, 21:28, William Donzelli wrote:
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
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.