amperage meter for system

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=108078
Printed Date: May 10, 2025 at 11:34 PM

Topic: amperage meter for system

Posted By: carlcom
Subject: amperage meter for system
Date Posted: October 10, 2008 at 6:03 PM

I have a LED voltage display ready for my dash and would like to add an amp display. I have 0 gauge from the battery to the trunk. I guess an Amp meter could measure the voltage difference and knowing the resistance of the 0 gauge, figure the amperage. Or an inductive clamp like the Fluke 321 meter. I'd rather not home build something but haven't seen anything for sale. Class AB rated 2500 watts means about 350 amps. Any ideas how best to do this?

Anyone know how the Soundstream capacitors measure it?

posted_image

Replies:

Posted By: haemphyst
Date Posted: October 10, 2008 at 7:11 PM

It's calld a "Shunt Resistor", and they will be rated in a given current range. Basically you then connect a VERY sensitive voltage meter across the ends of it, and measure the voltage drop across it. They are generally rated at X millivolts, at X current, so you will match your meter to this mV drop for X current. They are generally PRECISION devices, rated for tremendous current, as are the meters associated with them. I will locate some links, and post them for you.

Here's a really good explanation...

-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Posted By: forbidden
Date Posted: October 11, 2008 at 4:10 PM

If this is the same person who posted on CCA, here is the same link I gave there.

https://www.dakotadigital.com/index.cfm/page/ptype=results/Category_ID=243/home_id=59/mode=cat/cat243.htm

-------------
Top Secret, I can tell you but then my wife will kill me.

Posted By: carlcom
Date Posted: October 11, 2008 at 5:38 PM

Thank You for the Dakota Digital link! The Solarix series is almost exactly what I was hoping to find. I bit big but I'll make them fit, won't be the first time. It doesn't use a shunt so I won't have an extra .15V drop. And they're not made in China, a plus to me.

I'm thinking of getting the voltage meter to match and maybe the temp meter. Doing my part to help the economy!