How to measure DC current

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Price is not the driving issue.

Want something reliable. Would be great if it
could also be used on my grid-tied solar system at home.

A clamp on ammeter is very handy. However there are existing charts that will give you a very close assessment. What are you interested in measuring?

UNI-T UT203 Clamp Meter

P3 (P4400) Kill-a-watt

Bought mine on Ebay.

For example, MA120 for $75.00

Clamp on AC/DC Ammeter (only, no Volts) measures 0.1 to 199.9 AC or DC Amps

Do pay attention to specs if getting a clamp-on meter. Some only work with AC (depending primarily on how they detect current).

A traditional ammeter is often constructed of a millivoltmeter and a shunt resistance. If your multimeter can measure millivolts and you get an appropriate shunt, you can measure the voltage drop and find the current using math. A shunt is really just a low-ohm, reasonably high power resistor, with the resistance expressed as mV at some maximum current. A 50A 75mV shunt would have a 75 mV drop across it when 50A is going through it, which works out to a resistance of .0015? (1.5 m?) and a power rating of at least 3.75W.

I think most multimeters had at least some current measurement capabilities built in, though perhaps not the ranges that are useful for what you want to measure. Certainly both my Fluke 73 (a nice workhorse) and the super cheap generic analog meter (the one that stays in the RV) do: the former going up to 10A but no low-current ranges, the latter with only milliamp ranges.

bukzin,

keep in mind, you cannot measure amperage across a double cord (i.e; black and white inside casing) with a clamp meter. That's where the kill-a-watt comes in handy. The clamp meter is for checking current thru single battery cables and such.

The best thing would be to install a permanent ammeter in your coach.

First, install what they call a "shunt" in the main negative lead of your coach battery. Then, run a wire from this to wherever in the coach you would like a small and inexpensive digital meter to read current. (The shunt is not expensive either.) The meter will read negative (a "-" symbol ahead of the current reading) if current is going out of the battery and will positive (a "+" symbol ahead of the current reading) if current is going into the battery.

I've had this for years and it is real helpful for monitoring what current every 12V item in the RV is using and how well the batteries are performing and getting charged. I velcro'd the digital ammeter right on the dash where I can watch it as I drive or camp.

ah, good call. I wasn't even thinking along those lines.

The trimetric is mooey $$$, but very accurate, amp hour wise.

My 5 dollar volt meter has an amp setting that I used to measure all my DC loads. I disconnected the positive lead at the battery and touched the meter prongs while my DW turned everything on and off.