What meter to use on the DC shunt

Discussion about the Power System DC Disconnect (PSDC)

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West Texas
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What meter to use on the DC shunt

Post by West Texas » Fri Nov 24, 2006 4:39 pm

The PSDC comes with a shunt but I can not find any mention of it's use in any Outback manual. I am used to using shunts with Link or E-meters in marine applications. Why no info here?
I think knowing the total amps in/out would be good.
I'm I missing this info elsewhere in the system or what?
Thanks for the help.

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Post by Vic » Fri Nov 24, 2006 7:42 pm


Generally, shunts in commercial/scientific/industrial applications are called 50 MilliVolt shunts ... 50 MV at the rated max load of the shunt.

ALmost all shunts are marked with the max current rating (full-scale value), and usually the output voltage for that rated current. For example 250 Amps, 50 MV. etc.

I have no specific knowledge of the rating of this shunt, as ues Brand X conduit boxes here, and a TriMetric Amp Hour totalizer, but would be surprised if it was other than 50 MV.

So you need to use a VOLTMETER to read the volatge drop across the Resistance of the shunt. At a current of say one half of the max rating of the shunt, will yield 25 MilliVolts etc, it is linear one tenth of the current, is 5 MV etc.

If the current varies rapidly, a DVM will often be unable to show the average current. In cases like these, the voltage dorp needs to be integrated to give meaningful readings. A classic meter movement with a moving needle does the integration if you have one, and are interested in taking one-time or occassional readings. Some DMMs can integratea, and of course some computing will do so as well.

Am certain that the provided shunt is compatible with the other parts of the OB system. Such that if you plan to exclusively use OB components, you should not need to know anything about this shunt.

Just my opinions in general, Good Luck Vic
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Post by mvrck » Sat Nov 25, 2006 6:21 am

At this time, Outback has no device to connect to the shunt.

The shunt is a 50mV/500A type and I connected the Trimetric meter to mine.

See the details here: http://home.austin.rr.com/mvrck/misc/trimetric/trimetric2020.htm

I need to add a picture of the inside of the PS2DC showing the connections, but the meter comes with a great installation manual...

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