Installing an ammeter in a 12 volt system

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Old 02-19-19, 06:11 PM
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Installing an ammeter in a 12 volt system

My goal is to install an ammeter in the 12 volt system of my home made teardrop camper so I can see how many amps I'm pulling off of the battery bank (or + amps durring charging). To the best of my understanding I will need to install a shunt in series with the battery lead and wire the ammeter parallel to the shunt. Please excuse my terminology but feel completely welcome to correct me if I'm incorrect.
So far if this seems correct, my confusion is the fact that the battery lead is 2 gauge wire because that is what the inverter recomended. Does the shunt also have to be equivalent to the 2 gauge wire, if so does such a thing exist or am I completely off course here?
 
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Old 02-19-19, 06:57 PM
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The shunt needs to be sized for the wiring and maximum current. The wires to the meter can be quite small as the meter is only measuring the voltage drop across the shunt. The shunt has a fixed resistance so I (current)=V (voltage) / R (resistance)

Take a look at page 2: http://assets.bluesea.com/files/reso...tions/9322.pdf
 
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Old 02-19-19, 07:33 PM
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I have several precision shunts that were very expensive. I was just looking on Ebay. There are some sellers selling a digital meter and a shunt for a fraction of what I paid for one shunt. There are many different styles for sale. Most are from China. Be sure if you choose this route to make sure the shunt is included.

Ebay 200VDC 200A meter
 
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Old 02-28-19, 06:24 AM
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thanks

Thanks for the knowledge. I think for my purpose I may just reserch a non-contact ammeter. Seems easier and sufficient for what I'm trying to accomplish.
 
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Old 02-28-19, 10:45 AM
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Be sure your clamp-on ammeter will work with DC. A typical AC clamp-on will not read DC current.
 
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Old 02-28-19, 01:39 PM
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I may just reserch a non-contact ammeter.
Not a good choice. Most lamp ammeter works for AC only and the ones that work for DC needs to be reset before using.
Therefore, DC clamp meter is only good for testing purpose, not for a long term monitoring.

DC clamp ammeter uses hall effect sensor to measure current (measuring strength of magnetic field around a wire) and this even measure Earth's magnetic field and all other magnetic fields that may be passing through the meter. This magnetic fields changes depending on the location and the orientation. Therefore, it needs to be zeroed right before measuring.
 
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