# 500 Amp digital gauge

**URL:** <https://community.electricforum.com/t/500-amp-digital-gauge/869>\
**Category:** EV Small Talk\
**Created:** [July 31, 2008, 5:18pm UTC](https://community.electricforum.com/t/500-amp-digital-gauge/869 "2008-07-31T17:18:43Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![bblocher](https://avatars.discourse-cdn.com/v4/letter/b/13edae/32.png) [@bblocher](https://community.electricforum.com/u/bblocher)\
**Post date:** [July 31, 2008, 5:18pm UTC](https://community.electricforum.com/t/500-amp-digital-gauge/869/1 "2008-07-31T17:18:43Z")

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So I’ve been searching around for a digital gauge that can handle up to 500 Amps. I’m finding plenty of these. The problem I don’t understand is they say they are for a certain voltage (like 36 or 48, etc and nothing very high). Has anybody found a digital gauge that will work with 144v system and 500 amps?

I don’t think the voltage is what’s required to power the display as it should say a range (i.e. 5-24v).

Anyhow anybody who knows a little more about this, if you’d please educate me since I’m thinking I might be looking at this wrong.

Brian

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**Author:** ![Longez](https://avatars.discourse-cdn.com/v4/letter/l/c89c15/32.png) [@Longez](https://community.electricforum.com/u/Longez)\
**Post date:** [July 31, 2008, 5:37pm UTC](https://community.electricforum.com/t/500-amp-digital-gauge/869/2 "2008-07-31T17:37:23Z")

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Most digital Amp Meters are really just a volt meter in disguise measuring the voltage drop across a small resistance which may be a shunt supplyed with the Amp Meter or could even be a short section of your main wiring. If they supply the shunt they need to know the voltage you are running to adjust the readings of the volt meter to read Amps.

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**Author:** ![enganear](https://avatars.discourse-cdn.com/v4/letter/e/ed655f/32.png) [@enganear](https://community.electricforum.com/u/enganear)\
**Post date:** [August 3, 2008, 5:33am UTC](https://community.electricforum.com/t/500-amp-digital-gauge/869/3 "2008-08-03T05:33:23Z")

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[QUOTE=Longez;4351]Most digital Amp Meters are really just a volt meter in disguise measuring the voltage drop across a small resistance which may be a shunt supplyed with the Amp Meter or could even be a short section of your main wiring. If they supply the shunt they need to know the voltage you are running to adjust the readings of the volt meter to read Amps.[/QUOTE]

Mostly right. Amps are amps regardless of pack voltage and the measured voltage drop across a shunt is related to the current and is unrelated to the pack voltage. The voltage rating on the gage is related to the voltage required to power the electronics in the gage.  
-enganear

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**Author:** ![Longez](https://avatars.discourse-cdn.com/v4/letter/l/c89c15/32.png) [@Longez](https://community.electricforum.com/u/Longez)\
**Post date:** [August 3, 2008, 6:15am UTC](https://community.electricforum.com/t/500-amp-digital-gauge/869/4 "2008-08-03T06:15:37Z")

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Yes - I agree with you. I kinda thought I was going off on needing to know the supply volts to calculate amps via V drop across a shunt.

Thanks for the correction.

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**Author:** ![Engineer\_Bill](https://avatars.discourse-cdn.com/v4/letter/e/b5ac83/32.png) [@Engineer\_Bill](https://community.electricforum.com/u/Engineer_Bill)\
**Post date:** [August 31, 2008, 10:20am UTC](https://community.electricforum.com/t/500-amp-digital-gauge/869/5 "2008-08-31T10:20:45Z")

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You can run the digital ampmeter at less than the pack voltage, but check with the manufacturer about voltage potentials between the power source and the voltage at the shunt.