Digital ammeter/voltmeter with shunt wiring

[underdog]

I recently bought one of these http://www.ebay.co.uk/itm/390981389859?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT
Digital LED Dual Display Voltmeter DC 4.5-30V Ammeter 0-50A + Current Shunt

I am confused as to how to wire it. My understanding so far is:

It has five wires .
Red : To power + 9 volt battery
Black:To power neg 9 volt battery

Black: to shunt terminal 1 which in turn is connected directly to domestic battery negative.
Red: to positive. Where should i connect This?
Yellow: To other shunt terminal 2. from where should i lead a wire to this?

I only want to monitor the domestic 105 amp hr battery.Loads are relatively light: led lights, autohelm, Radio,Led nav lights,chartplotter, GPS, AIS.
I have a one, two or both switch
Charging from alternator on 1gm 10
All loads to negative bus bar and positive to individual fused switches on panel.

 

[sailorman]

I recently bought one of these http://www.ebay.co.uk/itm/390981389859?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT
Digital LED Dual Display Voltmeter DC 4.5-30V Ammeter 0-50A + Current Shunt

I am confused as to how to wire it. My understanding so far is:

It has five wires .
Red : To power + 9 volt battery
Black:To power neg 9 volt battery

Black: to shunt terminal 1 which in turn is connected directly to domestic battery negative. one of the big screws to the battery neg
Red: to positive. Where should i connect This? battery
Yellow: To other shunt terminal 2. from where should i lead a wire to this? neg to panel / dis board

I only want to monitor the domestic 105 amp hr battery.Loads are relatively light: led lights, autohelm, Radio,Led nav lights,chartplotter, GPS, AIS.
I have a one, two or both switch
Charging from alternator on 1gm 10
All loads to negative bus bar and positive to individual fused switches on panel.

Oh look here its on the ebay site

 

[underdog]

Many thanks.
I don,t trust my self to read wiring diagrams correctly! Hence I asked the question.

 

[NickRobinson]

Some, like this one, http://www.ebay.co.uk/itm/12V-20V-5...arts_Vehicles_CarParts_SM&hash=item1c4a6cf53e do not need a separate power supply. If this one is the same, I can't see why two negs and two pos's are needed.

 

[philip_stevens]

Sailorman has indicated where to put the leads - his RED in the quote box.

Red lead to the positive side of the battery.
Black lead to the negative side of the battery or terminal 1 of the shunt.
Yellow lead to the other side of the shunt - terminal 2.

Insert the shunt in the negative lead to the battery.

 

[VicS]

Some, like this one, http://www.ebay.co.uk/itm/12V-20V-5...arts_Vehicles_CarParts_SM&hash=item1c4a6cf53e do not need a separate power supply. If this one is the same, I can't see why two negs and two pos's are needed.

Its not the same! Some can be powered by the same supply that they are monitoring, like the one in your link, some cannot, like the one the OP has bought, requiring an independent power supply.

If he had asked for advice first he might have been guided to one which does not need a separate battery to power it, but he didn't he bought first then asked for advice!

 

[GHA]

i have the same meter but low power so the shunt is in the meter.
http://www.newfrog.com/p/dc-0-100v-...anel-amp-digital-volt-gauge-yb27va-29211.html

My scribbles from evernote..

g.

You'll have a shunt between the yellow/load junction and neg.

The same power CAN be used, in real life the two red power in's are connected and the bottom black power in neg isn't connected to anything.

Surprisingly accurate for the price, I got a couple and measure everything now

 

[pampas]

Some, like this one, http://www.ebay.co.uk/itm/12V-20V-5...arts_Vehicles_CarParts_SM&hash=item1c4a6cf53e do not need a separate power supply. If this one is the same, I can't see why two negs and two pos's are needed.

One set for shunt the other to measure voltage.

 

[sailorman]

This is the G/A of the monitor i have fitted



http://www.nasamarine.com/prodimages/one_battery_wiring1.pdf

 

[GHA]

Originally Posted by NickRobinson http://www.ybw.com/forums/showthread.php?p=5065317#post5065317
Some, like this one, http://www.ebay.co.uk/itm/12V-20V-5...arts_Vehicles_CarParts_SM&hash=item1c4a6cf53e do not need a separate power supply. If this one is the same, I can't see why two negs and two pos's are needed.

One set for shunt the other to measure voltage.

Don't think so, I just happened to have one nearby and alligator clipped it to a battery, the thin red and black are for powering the unit. Voltage is measured from the thick red. Thin black isn't needed if the same power being measured is powering the unit, ie if the thick black is attached to neg.

So somewhere on the yellow there must be a very accurate device measuring the very low voltage drop across the shunt?

I think the 2 blacks are commoned inside.