Any hints on shunt wiring, please?

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I took a punt on one of these to measure solar panel performance.
The only wiring instructions are those in the ebay listing:

About wiring: Red line thin: power supply+
Black line thin: power supply -
Red line (thick): PW+, measuring terminal voltage input positive
Yellow line (thick): IN+, current input
Black line thick: COM, common measuring

and they produce this:

IMAG0355_zpsc490e51b.jpg


The panel shows ~18V & 2.5A on my meter and if I disconnect the thick red altogether I get correct amperage but no volts. Any suggestions how to get both or is it duff?
 
Looking at the picture it suggests that the thin wires are simply to power up the meter. (a 9v volt battery is connected, but the reding is zero) I assume you have connected those wires straight to the battery?

Was the whole lot connected to the battery? If not the 18volt reding may just reflect the open circuit reading.
 
The small battery in the photo connected to the thin red and black wires powers the meter.

Can you confirm that the grey wires on the croc clips go to the 12v battery you wish to monitor and what load have you attached to the shunt for current measuring as a load is not shown.
 
View attachment 44058

This diagram is for a current meter and is very similar to your setup but you have an extra (red) wire to the shunt to measure voltage and an isolated power module is used instead of your small battery to power the meter.

For using in a charging circuit substitute load for solar panel etc.
 
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theoldsalt said:
The small battery in the photo connected to the thin red and black wires powers the meter.

Can you confirm that the grey wires on the croc clips go to the 12v battery you wish to monitor and what load have you attached to the shunt for current measuring as a load is not shown.
Click to expand...
He's wanting to monitor his solar panels I think. The voltage will be the same. The current reading should show what is going into the battery from the panels.
I thought the rig up was a picture from the supplier, but I may be wrong.
I can't work out what is connected to what.
 
It's my photo. The leads with croc clips are from 100W panel, the 9V battery is to power the meter.

Youtube vid is what I needed, thanks Neil..

Thanks for all for responses.
 
neilf39 said:
First few mins of this shows you how to wire it. Rest is interesting.

http://www.youtube.com/watch?v=1mpuF2Ss7J8
Click to expand...

At first viewing I found the wiring confusing so will have to study the video again. However the remainder of the video was very interesting and showed that the shunt supplied had not been calibrated to the meter so unless the buyer has the equipment to calibrate it then it seems of little use in displaying an accurate current consumption/charge.
 
Quiddle said:
It's my photo. The leads with croc clips are from 100W panel, the 9V battery is to power the meter.

Youtube vid is what I needed, thanks Neil..

Thanks for all for responses.
Click to expand...

In that case, if you connect it all to the battery, you should find everything is working properly.
 
Quiddle said:
It's my photo. The leads with croc clips are from 100W panel, the 9V battery is to power the meter.

Youtube vid is what I needed, thanks Neil..

Thanks for all for responses.
Click to expand...


But where is the battery that the panel is charging or the load. Neither is not shown in your photo. Is it in the circuit somewhere - the panel has to be connected to a battery or a load for current to flow.
 
theoldsalt said:
But where is the battery that the panel is charging or the load. Neither is not shown in your photo. Is it in the circuit somewhere - the panel has to be connected to a battery or a load for current to flow.
Click to expand...

Right, I'd assumed that as my multimeter showed V and A then this gizmo would. I just made a circuit with the + and - of the panel cables. Will connect to battery when I go to boat tomorrow.
 
Rigger Mortice said:
Correct, but I assumed the shunt was providing the load?
Click to expand...

No the shunt is not the load it is part of the measuring equipment. The meter indicates current by measuring the small voltage drop across the shunt resistance. Hence the accuracy of the current measurement depends largely on the accuracy of the shunt resistance.
 
theoldsalt said:
No the shunt is not the load it is part of the measuring equipment. The meter indicates current by measuring the small voltage drop across the shunt resistance. Hence the accuracy of the current measurement depends largely on the accuracy of the shunt resistance.
Click to expand...

Sorry, perhaps I wasn't being clear. I realise that the shunt is part of the measuring setup. What I was saying was that, in the photo, the load on the system was coming from the shunt......it does look as if it is wired across the panel.
 
Quiddle said:
Right, I'd assumed that as my multimeter showed V and A then this gizmo would. I just made a circuit with the + and - of the panel cables. Will connect to battery when I go to boat tomorrow.
Click to expand...

In the meantime you could use a 12v bulb as a load and then use the meter to check the output voltage of the solar panel and the current consumption of the bulb.

P.S. Don't forget that a charging regulator should be used in conjuction with the solar panels.

For example http://www.ebay.co.uk/itm/360684563165?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
 
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theoldsalt said:
In the meantime you could use a 12v bulb as a load and then use the meter to check the output voltage of the solar panel and the current consumption of the bulb.

P.S. Don't forget that a charging regulator should be used in conjuction with the solar panels.

For example http://www.ebay.co.uk/itm/360684563165?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Click to expand...

Cheers. I have a PWM regulator in my current system. Could you advise whether the amp/volt meter is better placed between the reg and batteries or between the panel and reg?
 
Quiddle said:
Cheers. I have a PWM regulator in my current system. Could you advise whether the amp/volt meter is better placed between the reg and batteries or between the panel and reg?
Click to expand...

That's a very good question and I'm not sure I'm best qualified to give a professional opinion. Hopefully an expert will advise.

However I would be inclined to use the Volt/Ammeter to measure the battery state rather than the solar panel output as it is usually battery condition that is the most important. If nothing else is switched on then the meter will indicate the charge from the panels. If other equipment is switched on the meter will tell you if you are draining the batteries or still charging them.

So my personal preference would be to connect the negative end of the shunt directly to the negative of your battery bank and connect all other equipment via a buzz bar which connects to the positive end of the shunt. That is how my boat is wired and how a shunt/meter is normally installed. The shunt should be capable of carrying the starter current. Some boats have a dedicated starter battery wired directly to the starter motor, so in that case the shunt would only be connected to the domestic batteries. The two banks of batteries (start & domestic) being charged by a smart split charger. Engine starting takes very little out of a battery and is soon replenished so monotoring is not really needed.(rather like your car)

If he meter only monitors the solar panels then even if the meter shows an output from the panels your batteries could still be discharging (instruments etc switched on) and you could end up with empty batteries without knowing it.
 
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Thanks again. I already have an amp-out and voltage monitor for the batteries, OEM by Jeanneau, so the idea of this was to enable rough calculations based on what is going in and coming out - a cheapo version of the NASA BM-1 really, where I do the maths.
 
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