ondawada wrote:
Ahoy, what size shunt (can I make one?) do I need for this gauge?
Specs:
D.C. Ammeter - range to 75 amps
Triplett Corp.
Hendricks Electric Inc.
Sticker on the back says:
EIL
Cat: 321T
RGE: 50 MVDC
SCL: 0-50 ?ADC (one of the letters is rubbed out, MADC?)
I have a 70A alternator and 220AH house battery capacity. I'd like to
do this myself if I can. I have a small shunt from a 12v battery
charger but I don't think that will work. If the correct answer is
"you need a 50mv, 70A shunt", where do I get one? Lot's of people
selling 100A, 500A etc for solar pannels. Thanks for your time.

You probably already have one.

The trick is to use the cable from your
alternator to your battery as the shunt.
Well, actually only a part of the cable.

Here's what you can do. Find out what
wire size connects the alternator to the
battery. It might be #6, for example.

Look up in a WM catalog, or online, the
resistance of whatever size wire you
have. It will be given in ohms per foot
or per thousand feet. What you want is
the number of ohms per foot, and that
will be a very small number.

If your meter is actually 50 mV full
scale, then you want, say, 100 amps to
correspond to 50 mV. Ohm's law says the
resistance that will give you a 50 mV
drop when 100 amps are flowing through
it is 0.005 ohms. (check that: I'm senile)

Since you already know the ohms/foot of
your wire, you can figure out how many
feet of that wire will give you a
resistance of 0.005 ohms. You don't need
a lot of precision here, or accuracy for
that matter. Who would ever believe you
anyway, especially when they find out
you made your own shunt!

Finally, you just cut through the
insulation (NOT the wire) on the wire at
two places that are the distance you
just calculated apart. Solder some
small, stranded, insulated wire to those
bare places and connect them to your 50
mV meter.

Be nice to seal the connections, etc.
But you can't beat the price.

Good luck.

Chuck




----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----