View Full Version : Wiring Shunt and amp meter

02-20-2011, 06:49 PM
I just got a DC 100A meter and DC 100A 75mV shunt . From the wiring diagram I've gotten with it, it seems like it's showing how to wire it up to see how much you are drawing..

I'm trying to hook mine up so I can see how much my panels are making.

this is one message I got from them:

The shunt must be in low side (near negative terminal), and DC 100A meter need to be connected in series in the circuit.
The meter and the shunt is parallel connection.

I wish I knew of a way to put this adobe file on here but don't heres what I've got from the picture

terminals 1 & 2 from the meter goes to the pos & neg of the battery.

3 is neg from the meter and hooks to the shunt (small terminal) large terminal on that side of the shunt goes to the neg. of battery.

Pos of the battery goes to the load. (could this be the charge controller)?pos or neg??? (you'll see why I ask.. lol)

The other side of the load goes to the other large terminal of the shunt.

On that side of the shunt the little terminal goes to the Pos terminal of the amp. meter

Please Help

02-21-2011, 01:04 PM
Jack, if you can find the website for your meter it might have the pdf file online so everyone could see what you're trying to work with. Since we can't see what you're looking at, it's kinda hard to understand.

02-22-2011, 01:04 PM
I couldn't find one and I asked the ppl I got it from and they said they do not have one on line....

there's got to be someone out there that has hooked a amp meter and a shunt to read their solar panel output.... :confused:

when I bought it I really didn't think there would be that much to it but the diagram they sent me seems kinda weird and don't want to burn this thing up... :lol:

02-22-2011, 02:02 PM
Just post the make/model number for each and maybe someone can find it somewhere else.

02-22-2011, 02:23 PM
Jack, I have no idea at all what your meter looks like or what the terminal connections are. But, in general, an ammeter is connected in series with the load, and a shunt is in parallel with the meter. If I could draw better with text, it would be easy to show. But, bear with me.

The (+) of the battery goes to the (+) of the meter and also to the (+) of the shunt (if there is one) . The (-) of the meter and the other end of the shunt goes to the (+) of the load. The (-) of the load goes to the (-) of the battery.

If the meter is between the panels and the batteries, the battery bank is the load.

If the meter is between the batteries and the load, obviously, the load is the load.

I have no idea if this will help you or not, I hope so.

02-22-2011, 06:39 PM
"DC 100A meter and DC 100A 75mV shunt"

First question.. Are you sure this is a matched set?

How it works..

Whatever load that you want to monitor, (panels to battery, loads in house) the shunt needs to be "inline" of the circuit. This means that whatever load will pass "through" the shunt and the meter will move with the current loss of the shunt.

The shunt is a resistor and will drop 75 mA. @ a 100 amp load through it. The meter shows how much current the shunt is dropping in the circuit. According to how much current is being dropped across the shunt, the meter will tell you how much load is on the circuit. The current loss of the shunt is what moves the meter.

If you want to monitor the current to you battery from your charge controller, you need to insert the shunt in either the positive or negative wire. Cut the wire and add the shunt where you cut the wire to reconnect them together. Much like adding a fuse to the wire.

Let's assume that you are adding the shunt to the positive lead between your battery and the charge controller..

I would add the shunt close to your charge controller to avoid corrosion issues from the battery. Either cut the wire or add a jumper. Insert the shunt inline. The battery will be your load. As current passes through the shunt, the current loss will be seen at the end of the shunt towards the battery. Connect the negative connection of your meter to this end. (Towards the battery) Connect the positive connection of your meter to the opposite end of the shunt. (Towards the charge controller) That should be all that there is to it.. ;)

02-23-2011, 10:10 PM
Ok what I'm tring to measure is the amp. that my solar panels are producing.

Yes it's a match set anyways this is the shunt that says goes with my amp meter..

Thanks for help

02-23-2011, 11:49 PM
Yep.. If you monitor the charge between the charge controller and the battery, you'll know how many amps are getting to your battery.

If you want to do a "short test" on your panels alone, you can still do this too..

Disconnect your panels from the charge controller and connect the pos/neg to each end of the shunt. Connect the pos. connection of the meter to the side that you connect the pos. wire from your panels to and the neg. to the neg. side. The shunt will short the panels out and allow a small amount of current to flow through the meter to make it move. The shunt may warm up some but it should handle 100 amps.. ;)

03-01-2011, 10:23 AM
So being hooked up like this you can't leave it hooked up to run continously can you???

can I run a wire (more or less) from the pos and neg to the shunt with say the pos run through a toggle switch to where I can switch it on/off so I can get a reading when I like to see it. And wire it up like you said. Would that be the best way to go

Thanks alot

03-02-2011, 09:39 PM
Yes.. You can install it and leave it in. You can run wiring from the shunt to the meter within a reasonable distance. (10' or so) There's no need for a switch. The insertion loss won't be noticed..

At a max load (100 amps) the current drop will be only 75 mA. across the shunt. (.075 amp)

03-02-2011, 10:20 PM
Ok thank you. I guess I'll have try it and see if I don't blow it up... lol


03-02-2011, 10:29 PM
Ya ain't gonna blow nuthin' up.. LOL

Just insert it like an inline fuse. If the meter goes backwards, just reverse the wires on the meter.. ;)

11-06-2011, 02:18 AM
Don't know if this is the exact same meter the OP has, but the spces are the same

This site


has step by step instructions and photos in the installation.

Hope future readers find this useful...

12-13-2011, 06:36 AM
Thank you that one looks like it will do it. I've kinda gave up on it.