Amp Gauge - Can it's range be modified

[Gary Warner]

I have purchased some gauges (Amp, Tach, Oil Pressure, Water Temp) all from
the same company (Classic Instruments) because I liked the look of them for
our boat. Problem is the ammeter range is -60 AMPS to +60 AMPS. On my
little boat the max amp draw even with everything running is probably under
20 amps and more like 5 or 10 most times.


Is there any easy & safe way to modify the gauge to change it's range?


The company does not offer any other range options for this gauge.

Thanks.
Gary

 

[Gary Warner]

By the way, the current draw for the starter does NOT pass through the
ammeter.

 

[Rick]

Is there any easy & safe way to modify the gauge to change it's range?

Looking at their web page, the ammeters are internally shunted so
without tearing the gauge apart to remove the shunt and installing an
external shunt and then dividing the reading there doesn't seem to be
much you can do.

Do you really care that much about the charge rate or system load? They
make a matching voltmeter that will provide useful information about the
status of your system.

Rick

 

[Gary Warner]

Do you really care that much about the charge rate or system load? They
make a matching voltmeter that will provide useful information about the
status of your system.

Rick

Thanks for taking the time to look at their site.

No, I don't care *that* much. It just bugs be a little that here I have
this
nice and somewhat expensive gauge and it really doesn't give me any
accuracy.
It does do it's job - I can see the pointer move just a little toward charge
or
discharge - which is all I *really* need.

I did put a nice volt-meter on my electrical panel. Didn't put it on the
dash
because there was only one free hole and the boat originally came with
an ammeter and I wanted to keep it original.

Again, Thanks.

 

[Rick]

I did put a nice volt-meter on my electrical panel. Didn't put it on the
dash because there was only one free hole and the boat originally came with
an ammeter and I wanted to keep it original.

Yes, I can understand that ... at this point I would buy the Classic
voltmeter for the dash and replace the electrical panel voltmeter with
an ammeter scaled for the load you normally see. That way both
instruments will give you valid information and since your Classic
instruments aren't really original but look and feel like they should no
one will be the wiser seeing a voltmeter instead of a pretty much
useless ammeter.

Rick

 

[Gary Warner]

Gary Warner wrote:


Yes, I can understand that ... at this point I would buy the Classic
voltmeter for the dash and replace the electrical panel voltmeter with
an ammeter scaled for the load you normally see. That way both
instruments will give you valid information and since your Classic
instruments aren't really original but look and feel like they should no
one will be the wiser seeing a voltmeter instead of a pretty much
useless ammeter.

Hmmm....good point.

 

[Bruce in Alaska]

I have the opposite problem.

I want to find a 100 amp, zero center. amp meter to monitor my overall
system..

My alternator and/or charer/invertor put out around 100 amps at the
beginning of a charge, while various tools and appliances draw as much as
10-15 amps each and can total, at times, 30-40 amps.

I don't have a sophisticated battery monitor system, but would like to
monitor the net gain or loss from the battery bank..

Right now I have a 100 amp meter that just drops below zero when the charge
is greater than the current being used. Not very accurate and may not be
good for the meter movement.

What you need to do is put a 100 Amp Shunt in series with the main
battery connection and then buy an appropriatly scaled Center Zero
Meter to connect to the shunt. Paul Hendricks at Hendricks Electric
at Fisherman's Terminal can set you up with this stuff.

Bruce in alaska

 

[Rick]

"Hendricks Electric at Fisherman's Terminal
can set you up with this stuff."

Not any more they can't. They closed quite a while ago ... another sign
of the times in the industry.

Rick

 

[Bruce in Alaska]

Not any more they can't. They closed quite a while ago ... another sign
of the times in the industry.

Rick

Ok Hmmmm, Oh well, it has been a while since I was down that direction.
Then go over to Lunde Electric and get the stuff from them. They
should have all that stuff in stock.

Bruce in alaska

 

[Trevor Dennis]

Bruce in Alaska writes

What you need to do is put a 100 Amp Shunt in series with the main
battery connection and then buy an appropriatly scaled Center Zero
Meter to connect to the shunt. Paul Hendricks at Hendricks Electric
at Fisherman's Terminal can set you up with this stuff.

For testing purposes you can use the batteries earth lead as a shunt,
and calibrate it with a known load, like a 4 amp nav light. A stout lead
is gonna be in the region of 5-10mV/100A, so you'd need a reasonable
Multimeter.