On Mon, 13 Nov 2000 09:41:26 -0500
Roger Turk <[EMAIL PROTECTED]> wrote:
> Four batteries would give you 6-volts. If you have a voltmeter, you can check
> to see if the batteries are good or bad. (Or go down to your nearest Radio
> Shack or ham radio store.)
A voltmeter will not tell you whether a battery is good or bad. If I go
out to my car right now and use a voltmeter to read the voltage on my car
battery I will get a reading of 12 volts. Then I can turn the headlight
switch on and leave it on all night long. By morning my headlights will
no longer be shining and I will know that I have a bad battery. If I then
turn off the headlight switch and use my voltmeter again to read the battery's
voltage, I will still get a reading of 12 volts. The battery passes the
voltage test, but it will not pass a load test because it won't provide even
enough power anymore to turn on my headlights. If it can't even turn on the
headlights, then of course I know that the starter motor won't run either.
My point is simply this: A good voltage reading does not necessarily mean
that a battery is good. You have to perform a load test. A voltmeter does
not do this.
Do not try the above experiment at home unless you have some very
understanding neighbors who can help you get your car started in the morning
while you enthrall them with your amazing story about your adventure in
science.
All the best,
Sam Heywood
