I need to measure 50 - 60 amps of DC current. I realize a shunt resistor for a milliamp meter is probably not practical. I have seen clamp-on meters that can measure AC or DC current, but they're rather expensive.

So, how can I make a clamp-on (or regular) meter to measure high DC current?

 

Hall effect sensor/ split iron core then the associated electronics to scale/present a proper calibrated value.. Its not a "simple" task as calibration/hall sensor placement,etc..can be tough for a DIY project.

But personally I would simply buy a 50mv 100 Amp "shunt" and measure the voltage coming off it with your dc voltmeter. Something like this http://www.mouser.com/ProductDetail...-01099-0/?qs=sGAEpiMZZMukgiigmf73gCjDvzQf9eP1

100A would be 50mv, 50A would be 25mv.. you can take it from there.

 

Just use a very small 0.01 ohm resistor with high wattage (50 watt).
http://www.talonix.com/shop/item.aspx?itemid=8651

 

Just use a very small 0.01 ohm resistor with high wattage (50 watt).
http://www.talonix.com/shop/item.aspx?itemid=8651

Thanks. I ordered one.

 

What do you call expensive there are some on Ebay

 

If you don't need good accuracy i.e.+/- 10% Blue Point used to make an ammeter suitable for the 50A range you are talking about.
They had no electronics and solely relied on the deflection of a needle with a magnet attached which was attracted/repelled by the magnetic field generated by the current in the wire.
Great little too still working almost 35 years later.
You could easily enough make your own with a cheap magnetic compass and a lot of time to do the calibrations.