Why do mA and A settings on multimeter give different result?

[Rob Plant]

With apologies in advance for the newbie question...
I'm using a multimeter to figure out the source of my battery drain, so attempting to measure the leakage current between my battery terminal and its lead. When taking the readings shown below, they are quite steady, but as you can see, on the 10A setting I get a measurement of (-)69 mA, while on the mA setting I get 1.5 mA. Is this just because of the lower resolution (and higher error) in the 10A mode? I ask because online how-to information for doing this say to do the check in the 10A mode, and to be concerned if the current is more than about 50 mA. Based on the mA settign reading, I see no problem, but is there reason for concern based on the 10A reading?
I'd appreciate any pointers - thanks!
Rob

 

[Mikegh]

I didn't realize how accurate these M.meters are even on very low measurements. I have a a 6200ohm resistance that I use to test/trip my RCDs (30ma) and when i connected this across the ma scale I got 2.1milliamps, theoretically 2.026 milliamps with the battery at 12.56V.

Wouldn't surprise I've a little 10 euro dmm and when I checked it was bang on over a range of resistance measurements

Fluke T5 I have I wouldn't trust any reading off it

 

[pc1966]

I didn't realize how accurate these M.meters are even on very low measurements.

Even fairly cheap DMM are pretty good on DC volts, many are specified as 1% but often a bit better than that when new. DC current is usually poorer than DC volts even on expensive meters as it is much harder to get very high accuracy low-resistance shunts.

But what you normally have to pay more for is high accuracy true RMS for AC, accuracy that lasts over time & temperature range, and to have a meter that is measurement category CAT-III / CAT-IV rated. This last point is essential for safe use on systems like mains power where fault currents can be well over kA and voltage spikes can go to several kV due to far-away lightning or the switching of large motors, etc.

Measurement category - Wikipedia

en.wikipedia.org

If you only ever use if for traditional automotive circuits that is not much of an issue, but I expect EV / hybrid cars also have quite a nasty surprise waiting if you make a mistake with a DMM (e.g. on amps when you go to measure volts, etc)