Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Default Gas powered battery charger.

On Wed, 11 Feb 2009 10:26:11 -0600, RoyJ
wrote:

You have to watch the Ford units: the early ones had positive ground,
many of the later ones had external voltage regulator. I just prefer the
Delco units for ease of install for odd ball applications.

David Lesher wrote:
Some good ideas here. As suggested, you can hang an alternator off a
rotary lawn mower, and it's already got its own wheels. And there are
LOTS of abandoned lawn mowers. Take mine, please! Now, if you find one
with electric start....

But I also like the link to the guy selling the fits-all mounting plate.

In any case, you do want the alternator with an integral regulator. It's
also lots easier if you have a battery on the unit; both to provide
the needed excitation to the field and a low impedence load to the
alternator. The smallest lawn tractor battery will do.

There's a wide variety of alternators available at the auto boneyard;
case size is pretty much an indication of max. output.... If I recall,
Ford did things the opposite of GM, regulating the top end of the field
vice the bottom, but that shouldn't matter much.


NO american alternator was positive ground.
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On Wed, 11 Feb 2009 10:30:11 -0600, RoyJ
wrote:

if you want something really small, my local has new gas string trimmers
for $50. Tiny engine, ~34 cc, about a horse, nice little centrifugal
clutch, About 10 pounds with gas tank. Direct couple to a junkyard
Delco, should be able to get it under 25 pounds, fit in a 12"x8"x8" space.


A 34 cc engine will NOT drive a DelcoTron direct drive. Th 1 HP is
produced at high speed and there is little torque.
RogerN wrote:
wrote in message news:d82ffccf-fad7-4a08-a367-
...

A good idea, BUT....work out how much motor power you would need to
get the alternator up to 70 amps...not a small motor....and coupling
it to the motor is no trivial matter either - but thats OK, no way
could you charge a battery at 70 amps anyway...let us know how you get
on, if you have the bits lying around then it would be fun - btw, you
would need to work out pulley ratios to get the alternator into its
power band without revving the motor to blazes - and some sort of
governor..(only if your obsessive...)

Andrew VK3BFA.


I was thinking about something like a 3hp Briggs & Stratton that already has
a governor. IIRC, those engines have a maximum RPM around 3600 so if I used
a pulley twice the diameter of the alternator pulley it would give me up to
7200 RPM on the alternator. All my autos that have tachometers show from
2000 to 2600 rpm at 60mph. The engine pulley looks (haven't measured yet)
to be 3 to 4 times the diameter of the alternator pulley. That would spin
the alternator maybe 6000 to 10,000 rpm. In my car when I have the lights
and heater on, at idle the lights dim and the fan slows, when I get over
about 1200 rpm things pick back up.

For experimenting, I could get a used lawn mower and cut the engine hole
pattern in a flat plate. Then cut holes for mounting the alternator and
install pulley and belt. It would be ideal if I could find a mower with a
deck flat enough to mount the alternator, kind of like a riding mower mount.

It would be nice to find a smaller lighter motor maybe perhaps a chainsaw
engine or good weed eater engine.

RogerN



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On Wed, 11 Feb 2009 10:26:11 -0600, RoyJ
wrote:

You have to watch the Ford units: the early ones had positive ground,
many of the later ones had external voltage regulator. I just prefer the
Delco units for ease of install for odd ball applications.


I have not ever seen a positive ground alternator; at least in automotive
applications. [Telco, however....]

Given the near-infinite supply of Delco units, I agree it's easy to
find one. But there's no reason to discard a good Ford unit with
regulator.....

I gave a friend a 150A/28VDC unit many years ago; it would be easy to
regulate it to 14V and would have made a kick-ass car-starter.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
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Default Gas powered battery charger.

You don't want a weed eater or similar engine. The noise will drive you
nuts and, weed eaters particularly, won't last very long in that
application.

I, too built what you suggest 30 years ago. Using no regulator at all,
I had to touch the battery lead to the field terminal for a second or so
to excite the field, then it worked fine. Our application was to charge
a large RV battery. We would fill up the tank when we left the place
and let the engine charge the battery until it ran out of gas. Worked
well. The engine was a 2 1/2 HP Briggs horizontal shaft. Mounted the
whole works on a 2 X 10 board about 2 feet long. Made a handel out of
some pipe and a tee.

Another thought:
Mount the alternator on a bicycle that is on a stand. I did this
years ago, too. I welded a piece of 2" water pipe to the pulley to
contact the wheel Added a field rheostat and a couple of meters. I
could get about 10 amps out of me for an hour or two without too much
strain. It made a great exer-cycle because I had infinite "load"
control with the field rheostat.
In my case, I put the rear wheel between the front forks and attached
the chain to it. It was easier to make a solid stand for the forks.
----GenaBike-----



Pete Stanaitis
-------------

RogerN wrote:

I've been thinking about mounting an automotive alternator on a small
gasoline engine to make a portable battery charger with respectable output.
The purpose would be to charge auto batteries when there are no outlets
around. Of course you could do the same thing with a generator and battery
charger but I think you can get perhaps 70 amps or more from an alternator.
It would have been nice this winter when we had the ice & snow storm and the
battery was weak on the seldom driven 4WD diesel truck. Also could be
useful for camping and boating, could recharge the trolling motor battery on
the lake, etc...

RogerN


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RoyJ writes:

You have to watch the Ford units: the early ones had positive ground,
many of the later ones had external voltage regulator. I just prefer the
Delco units for ease of install for odd ball applications.



I have never ever seen a positive ground automotive alternator.
If anyone had same....it HAD to be British/Lucas...

What year US Fords were 12v positive ground?

What is different in Fords is the end of the field regulated:

GM
MOPAR
Most everyone:

+12v {via idiot lamp}
\
/ field winding via slip rings
\
/
\
/
\
/
\
/
\
/
\
/
[regulator]
Ground

[GM had a hidden "full field" test point; ground it to bypass the
internal regulator, and the alternator puts out 100%]

Ford;

+12v {via idiot lamp}
|
[regulator]
\
/ field winding via slip rings
\
/
\
/
\
/
\
/
\
/
\
/
Ground

Ford put the regulator in the top end, but the alternator still made
+13.8VDC....that's a function of the diodes...





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Oh piffle... I just responded to a month-old post. Sorry.
"There's nothing more to see here; get back to your home directories.."

[I looked at the date "11th, that's yesterday..."...]

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
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"David Lesher" wrote in message
...
RoyJ writes:

You have to watch the Ford units: the early ones had positive ground,
many of the later ones had external voltage regulator. I just prefer the
Delco units for ease of install for odd ball applications.



I have never ever seen a positive ground automotive alternator.
If anyone had same....it HAD to be British/Lucas...

What year US Fords were 12v positive ground?

What is different in Fords is the end of the field regulated:

GM
MOPAR
Most everyone:



just FYI, my morgan +4 was 12V pos ground from the factory, I changed it to
neg ground so I could more easily run a radio


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"Bill Noble" writes:

I have never ever seen a positive ground automotive alternator.
If anyone had same....it HAD to be British/Lucas...

....



just FYI, my morgan +4 was 12V pos ground from the factory, I changed it to
neg ground so I could more easily run a radio


As is my BiL's +4; and GUESS who made the generator?
(Hint: also known as The Prince of Darkness....)


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
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Default Gas powered battery charger.

On Sat, 14 Mar 2009 03:21:07 +0000 (UTC), David Lesher
wrote:

"Bill Noble" writes:

I have never ever seen a positive ground automotive alternator.
If anyone had same....it HAD to be British/Lucas...

...



just FYI, my morgan +4 was 12V pos ground from the factory, I changed it to
neg ground so I could more easily run a radio


As is my BiL's +4; and GUESS who made the generator?
(Hint: also known as The Prince of Darkness....)

Are Land Rovers still positive ground? The old ones were I recall.
Gerry :-)}
London, Canada
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