Arnie, start where it says START HERE. Quit when you get tired. :-)

On Sat, 14 Aug 2010 18:48:01 -0700 (PDT), "hr(bob) "
wrote:

On Aug 14, 7:32*pm, mm wrote:
On Sat, 14 Aug 2010 19:31:36 GMT, Home@Home. (* US *) wrote:

Did a stupid thing and ran down the battery. *Now it's on a 12V 2/6
amp charger. *Every two hrs., I remove the charger from the AC source,
negative ground clamp, and positive clamp and attempt to crank the
engine.

A slow charge is best**. *When I used my 1 amp charger on a full size
car battery, for a big car, it took 24 hours to charge from dead.
Since yours is 2 amp, I'd figure 12 hours, or less if the battery is
smaller. *Maybe a little les yet since 24 might not have been needed.

If set on 6 amps, 4 hours of course.

**Although some fancy new ones say they charge 80% fast and then slow
down towards the end. I don't know about that.

Is is necessary for safety purposes to disable the charger, or can I
leave it connected while testing to see if the engine cranks over?

Now I use a 10 amp charger and I can often get by on ten minutes or
less before it will start**, and I don't disconnect it before trying.
But they aren't the original diodes, so I guess that doesn't help you.
I couldn't get those square, cracker-like selenium diodes anymore, so
I used a bunch of 2 amp tophat diodes in parallel***.

**I've disabled my lights-on buzzer switch for complicated reasons.

START HERE

***The original story of the 10 amp charger is more intersting. *35
years ago, I found it with nothing nearby on the sidewalk in Queens.
Took it home and it woudln't work. *Bad diodes. *Looked all over NYC, including industrial listings,
for selenium diodes that could carry 10 amps. * Didn't know why they
should be selenium, but that's what they used in the first place.

Coudn't find them, forgot out the thing for 5 years, and when I tried
again to fix it, it worked fine. I don't use it often but it worked
fine for 20 years. Then the diodes went bad again!! *Go figure.



Thanks.- Hide quoted text -

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Selenium diodes were 1930's, 1940's, and very early 1950's, they were
used because there were no other diodes available that could take the
current thru them that the selenium diodes could take. Modern-day
diodes came along in the early 1950's just before the invention of the
transistor at Bell Laboratories revolutionized the world as we know it
today.

Thanks. Very interesting. No wonder I couldn't find them. I found
the charger between 1970 and 1978, and it's the kind that a gas
station would have had, with a heavy duty 6/off/12 volt switch, an
ammeter, long heavy leads with big alligator clips, extra-length
hoizontal legs to keep it from falling over, and a rounded comfortable
metal handle, so it could have been 20 years old when I found it.
That would make it about 55 years old now, all original except the
diodes and the wires to the alligator clips (which were cracking all
over the place and all the way to the copper when I replaced them 10
or 20 years ago.)


I got my one-amp charger from my cousin Morris, who gave me his '50
Oldmobile in 1965, when I was 18 and he was at least over 80 and not
going to drive anymore. At the same time he gave me the battery
charger. The car had a 6-volt battery but the charger would do either
6 or 12 volts. It looked like new but I'm sure he didn't buy it the
last year he had the car. It doesn't look older than 1955? because it
still has a modern look, with a glossy almost metallic paint finish on
five sides and a face plate that still looks modern also (not that I
know what face-plates looked like in the 50's. And a plastic slide
switch for 6 to 12 volts.


That charger also had selenium diode in a bridge arrangement and
though it failed too, I found a simllar replacement. The original
ones fit in the case of course, but the replacement which I got at a
surplus store in the 70's was about the size of two cigarrette packs
front to back, so it had to be mounted standing on the top of the
whole thing, making it look like some sort of robot head.

What's most interesting about it was that I had the car in Chicago for
one winter and it was very cold, so I ran an extension cord from the
pantry of the house we lived in to the sign at parking lot in the
back. I placed the charger in an empty space near the battery and ran
the cord out the grill. Every time I parked, I plugged the car in and
left it that way until I left again.

ONce it got caught in the radiator fan and the wires ripped out, but I
repaired that.

But the 6 volts didn't seem to do a good job of charging it so I put
it on 12 volts. It had a glass circuit breaker that looked like like
a little Xmas tree light (with no light). A little over a half-inch
long and less than a quarter inch in diameter. It would trip every
90 seconds and reset 30 seconds later. Since I went to school in
walking distance, the car was home more than 90% of the time, and the
circuit breaker reset every 2 minutes for the whole winter. 720 times
a a day for at least 90 days, at least 7000 times. But that part
still works fine.

The whole thing works fine, but I'm too impatient to use it for car
batteries now.