help needed wiring up 100 Amp Ampmeter with shunt

Submitted: Sunday, Jan 16, 2011 at 20:15
ThreadID: 83698 Views:5710 Replies:3 FollowUps:1
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I just bought a 12 volt 100 Amp meter with shunt and am a little uncertain as to how to wire it into my dual battery system. I want to measure the charge going into the aux battery. I have a sidewinder battery isolator fitted and 200 a/h agm aux battery. How is the shunt connected into the circuit. I would assume that the + end of the shunt would connect to the wire coming from the isolater and the other end would connect to the wire going to the aux battery + terminal. I dont want to break the meter so advise would be welcome. The instructions supplied with the meter are a little vague.

Thanks Kc
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Reply By: Member - Murray R (VIC) - Sunday, Jan 16, 2011 at 22:05

Sunday, Jan 16, 2011 at 22:05
You wire the shunt in as you have assumed, you then connect the two thin wires from the ammeter with one to either side of the shunt. If your meter reads the wrong way reverse the two thin wires. The ammeter it self is a volt meter and reads the voltage drop over the shunt when current passes through it. If you want to read what is going in and out of your aux battery you connect the wire that supplies all your loads from the aux battery to the main battery side of the shunt. Seeing that your using a 100 amp meter a discharge of 10 amps will not show up much on the meter. Hope this helps.

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AnswerID: 442057

Follow Up By: Old_Bob - Monday, Jan 17, 2011 at 18:54

Monday, Jan 17, 2011 at 18:54
Actually it's the other way round, all analogue meters are ammeters with suitable sized shunts and for different ranges. when used as a volt meter they display the current flowing through a known set of resistances (shunt and dividers) and the display is marked as volts. If you check out the face of most meter movements you will see a figure ie. 100uA FSD this means that it takes 100 micro amps to drive the meter to the full scale, regardless of voltage.
FollowupID: 714220

Reply By: ABR - SIDEWINDER - Sunday, Jan 16, 2011 at 23:37

Sunday, Jan 16, 2011 at 23:37
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AnswerID: 442062

Reply By: kcandco - Tuesday, Jan 18, 2011 at 21:34

Tuesday, Jan 18, 2011 at 21:34
Thanks I can go ahead now with confidence.

regards Kc
AnswerID: 442273

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