Inexpensive Amp gauge

[(unknown)]

I've been needing a amp gauge to mount near my controller and I seen one on eBay for less than $5 shipped to my door. About a week later it arrived so I went out to test and play with it. I connected it to a 4 amp DC light and it pegged the 20a meter. It was connected proper but it had no shunt resistor.

I tested resistance of the meter and it ended up being 75mV.

Now I needed a shunt.

I had a piece of #12 copper wire (and with help) was able to determine the spacing of the meter leads to solder to this piece of 12ga wire. Here's how it went:

#12 is 1.588 / 1000'  0.001588 ohms / foot

75mV / 20A = 0.00375 ohms

.00375 / 0.001588 =

2.36', or 28.34" space between leads of the amp meter soldered to the #12

I used my HF meter to check the amps of a DC source and compared that to the meter reading on my analogue DC amp meter. They matched almost exactly at 4 amps.

Close enough to see how many amps my 5'7" dual rotor is putting into the battery.

Cheap and effective.

(Thanks Glen....)

Fused

[ghurd]

Looks Great!

G-

[tanner0441]

Hi

I bought a 15A version of that meter and it doesn't need an external shunt. I have it with a volt meter mounted on a dead inverter case. I find it very useful especially if the voltage or current reading is unstable, you can see the needle moving where a digital meter looks like a fruit machine.

Brian

[Fused]

Hi Brian

The Ebay seller made no mention that this gauge would not work as ordered.

I was shocked when it buried the needle with 4 amps going through it.

Thank God for smart fellas like Ghurd, he's the man. He walked me through it all.

Fused

[Tritium]

Yea I bought a 400 amp meter from e-bay to find out it was a 50mA meter with a 400 amp scale. Needed a 500A shunt to make it work.

Thurmond