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

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

On Mon, 22 Sep 2003 14:51:34 +0000, Gary Warner wrote:


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

No, but the alternator charging current probably does...

It's easy to modify an ammeter to make it read HIGHER (just put in a
shunt resistor across the terminals), but harder to make it read lower.
You'd have to replace the existing shunt resistor, probably internal to
the meter.

I solved the problem of small drain/large charging current by having
separate load and charging ammeters: a 10A for the load meter and a 50A
for the charging cct.

Lloyd Sumpter
"Far Cove" Catalina 36

Gary Warner wrote:

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

"Rick" wrote in message
...

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.

Gary Warner wrote:

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

Typical ammeter and voltmeter aren't really very useful other than
getting a very general idea of battery status. Analog meters
(with needles) are particularly poor. Something like a Link 10,
or E-Meter (same thing) is a much better investment.

Doug

"Gary Warner" wrote in message
...

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

"Rick" wrote in message
...
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.

"Lloyd Sumpter"

I solved the problem of small drain/large charging current by having
separate load and charging ammeters: a 10A for the load meter and a 50A
for the charging cct.

Lloyd Sumpter
"Far Cove" Catalina 36


Lloyd

Are you using FETs or Schottkeys to isolate charging vs load? Seems
like half a volt would be alot to give up.

BBJ

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.


--
Steve
s/v Good Intentions