# How to wire this current sensing board?

#### sdowney717

Joined Jul 18, 2012
648
I connected board power 12v + and - wires that are fused for the marine radio and the LED lights up with some numbers.
The negative - power connection is the same as one of the current sense connections looking at back of board.
I thought the radio negative to battery might go to the current sense side, but no, the radio would not turn on, and when wired that way, it blew the 10 amp fuse for the battery.
When measuring ohms across the sense terminals, it read 2 million ohms whether powered on or not.
I dont understand how this is supposed to work.

Here is the device, can someone please tell me how to wire this up?
Or if its defective?

And is there some better board I can buy to measure DC current and flip a relay on and off?

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#### narkeleptk

Joined Mar 11, 2019
465
Just guessing but it looks like you have on the right side
>12V to Power +
>Gnd to Power -

#### sdowney717

Joined Jul 18, 2012
648
Just guessing but it looks like you have on the right side
>12V to Power +
>Gnd to Power -

View attachment 186422
What exactly means the "load supply to com"?

#### sdowney717

Joined Jul 18, 2012
648
I am going to give up and claim its defective, shorted or something, unless someone can tell me what the load wiring is exactly, polarity etc...IMO, it should be the negative return coming from the device to be measured, except that blows the 10 amp fuse. If it was the positive wire would make no sense as it would be an instant short.

I am assuming to measure current flow, the sense terminals are wired in series with the device negative wires back to the battery.

So now I need a board to measure current flow for my marine radio, such that if when I broadcast a vhf signal by keying the mic, it senses the added current and flips a relay on. Any ideas?

Joined Jan 15, 2015
5,509
What exactly means the "load supply to com"?
It means looking at the image narkeleptk was kind enough to post that the input power negative and the load negative are tied. That is what it reflects in this link when looking at the board bottom. This board is made to do what you want to do.

Ron

#### ElectricSpidey

Joined Dec 2, 2017
1,175
Would you like a diagram?

Here ya go...

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#### sdowney717

Joined Jul 18, 2012
648
Would you like a diagram?

Here ya go...

View attachment 186430
How interesting, maybe it will work, I would have never thought of that.
That is very good of you to point me in that direction. Thanks.

#### sdowney717

Joined Jul 18, 2012
648
I have board set to PI1 mode with i1 at 1.00 amp.
Radio on draws less than 0.5 amps. Key mic amps ramp high. Relay never moves. What is wrong?
Video showing everything.
https://photos.app.goo.gl/GmeF4eqLDyHP612d6
Is board defective? Meter pos probe is on NC of relay, common of relay has 12v pos. Meter ground on neg wire.

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#### ElectricSpidey

Joined Dec 2, 2017
1,175
Hard to say, when you push the button it says P11, then changes to 1.00, then it changes to 0.10 so it's hard to tell what current the unit is set to from the video.

Could be set to 0.10 have you made sure it's set above .34?

If you keep the button pressed does it change to 0.10 then 0.20 then 0.30...etc?

It's flashing 0.10 when you release the button.

#### sdowney717

Joined Jul 18, 2012
648
Hard to say, when you push the button it says P11, then changes to 1.00, then it changes to 0.10 so it's hard to tell what current the unit is set to from the video.

Could be set to 0.10 have you made sure it's set above .34?

If you keep the button pressed does it change to 0.10 then 0.20 then 0.30...etc?

It's flashing 0.10 when you release the button.
The first amp number is 1.00 amps. When it flashes you move either number higher or lower pressing k2 and k3 buttons. The second number not sure what it does on function PI1.
Why put second number above .34?

#### sdowney717

Joined Jul 18, 2012
648
Ok. I set 2nd number at 0.35. Made no difference.
If current rises above 1.0 amps, relay ought to move

#### ElectricSpidey

Joined Dec 2, 2017
1,175
You have to set the current above .34 because that is where the display is saying the current is when the mic is off hook.

When you have it in 1.00 amp mode try pressing the other button until you see 0.50 on the display.

#### sdowney717

Joined Jul 18, 2012
648
You have to set the current above .34 because that is where the display is saying the current is when the mic is off hook.

When you have it in 1.00 amp mode try pressing the other button until you see 0.50 on the display.
Ok, set to 0.54. No help.

#### ElectricSpidey

Joined Dec 2, 2017
1,175
Well, it seems to be reading the radio current properly, so I guess there are 3 possibilities.

1. It's defective
2. Something was damaged when you set it up the first time.
3. The unit is still not set up properly.

I have no way to determine the third.

Sorry, I couldn't be more help.

#### sdowney717

Joined Jul 18, 2012
648
Well, it seems to be reading the radio current properly, so I guess there are 3 possibilities.

1. It's defective
2. Something was damaged when you set it up the first time.
3. The unit is still not set up properly.

I have no way to determine the third.

Sorry, I couldn't be more help.
Thanks for trying. It is defective. It only has use right now as a 0-10 amp meter. And it is rated at 10 amps and blew a 10 amp fast fuse, so I doubt its damaged. It is junk. I have bought a lot of junk over the years and sometimes you can make even junk work.

#### sdowney717

Joined Jul 18, 2012
648
I noticed something, this module I got does not match their own sellers picture, the one I got has a different circuit, has a large K7 diode sitting above middle button.
Look at this one on ebay, its good, having understandable instructions, except they messed up k2 and k3 up and down wording.
https://www.ebay.com/itm/5-12-24V-0-10A-DC-Current-Detection-Relay-Module-Overcurrent-Protection-YYI-2/183804847825?_trkparms=aid=555021&algo=PL.SIMRVI&ao=1&asc=59653&meid=53de888e25864d11b998f6ae3f2b6848&pid=100752&rk=4&rkt=7&mehot=wa&sd=264335212646&itm=183804847825&pmt=1&noa=0&pg=2047675&_trksid=p2047675.c100752.m1982

look at this on aliexpress, looks same as ebay one, but DOES NOT match what I got sent.
https://www.aliexpress.com/item/4000028199776.html?spm=a2g0s.9042311.0.0.38f14c4dfcEpcW

But look at the one I got, its very different. I got an inferior older defective circuit, it may be a bunch of failed devices the seller is unloading.
Here is my picture

I decided to try one more time, bought a board from Amazon, for $11, not the cheaper$9 with terrible instructions that make no sense.... looks like its the same board, but hopefully it will work. The amazon seller also has clearer to comprehend instructions. On function PI1, the only amp number that matters is the first one or for me, 1 amp. I actually set it to 1 amp as when I turn up the volume amp use goes to 1.6 amps, so its better test than broadcasting a signal.