My sears clamp on meter agrees closely with my IPN pro remote battery monitors shunted ammeter, and has higher resolution to 0.01amps, whereas the IPN pro remote is only to 0.1a. i have tested it on a single t10 LED and inline on a cheapo harbor fright DMM inline on the circuit and they agreed within 0.01a. @ 0.08amps, which inspired some confidence that both were fairly accurate
The other shunted meter i have experience with was a Drok 100 amp amazon special, and this one was much less accurate, especially at lower currents. The Drok would read 0.0 amps when 0,78 amps were still flowing. From 1.4 amp to 100 amps it was pretty close with my Sears craftsman clamp on meter:
http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P
I have not compared its reading to a known higher quality clamp on meter like a Fluke. I can say that its accuracy is crap when using rechargeable NiMh AAA to power it, compared to duracell alkaline AAA batteries.
The 100 amp Drok shunted ammeter/voltmeter combo was able to be calibrated but it could never read low currents under 0.78 amps, it would just read zero no matter how I calibrated it, even biased completely toward the lower end. This was on a 'portable' powerpack project for a friend, and only counted charging amps anyway. For his battery( lifeline gpl-31XT) when amps tapered to 0.625a the battery could be considered fully charged. So it reading zero when 0.78 amps were still flowing was frustrating. I had to give him directions to force the PD9245 to hold 14.4v for another hour after amps read zero on the Drok to ensure a true 100% recharge. but there is still room for error in this ''hour' as the time it takes for amperage to taper to 0.5% of battery capacity will vary greatly depending on the use the battery has seen since its last full charge.
I had really taken all steps regarding connections at the shunt itself to reduce room for error, but these steps were in vain as the meter was just not sensitive enough, or perhaps the cheapo Shunt's resistance not well matched for what the meter was designed to see.
That's All I got at this point. I'd enjoy being able to test one of these hall effect ammeters in the OP for accuracy, but I have not been financially responsible enough to dip into my want list.
I also have used the GTpower RC type wattmeters. these can also have issues with currents in the 0.4a or less range, however I had one which read down to 0.02 accurately when compared to my clamp on meter. that one went with the powerpack project to help my friend see how much he was using from the battery. This watt meter tends to read a bit high at 40 amps, reading 40.89 compared to the clamp ons 39.98a.
Close enough though. I love accuracy but a shoulder shrug has to be employed when inexpensive chinese products are purchased.
