If I am using this thing correctly (I did rtfm) then I'm measuring about .7-.8 amps when the fridge is plugged in and not operating. then more like 6-7 amps when the compressor turns on. Do you guys agree with those numbers?
It sort of agrees with what I've measured on an ARB Danfoss.
Running it was around 4.5A averaged with about 1.25V of ripple. I was a max of 5.12A and a min of 3.86A due to (apparently) the motor.
Power put on the connector but display off was 38mA (e.g. the constant parasitic even turned off).
Idle is about 65mA, which is display on with compressor NOT running.
The low current measurements were using the internal shunt on a Fluke DMM. The compressor measurements were done with a Fluke Y8100 clamp on current probe.
Your powered off still seems very high and I'd be dubious that the meter can accurately measure small currents. You should do a hasty calibration with a 50 ohm resistor. When put on a normal car battery this will allow around 250mA (calculated using Ohm's Law I=V/R thus 12.5V/50 = 0.25 = 250mA) and see what the meter tells you.
BTW, the actual resistor doesn't have to be 50 ohm but less than 100 ohms to keep currents in roughly the approx range and more than about 20 ohms to prevent needing to use a monster heat dissipating one. If you have a dummy load you'd use for tuning up a ham radio that would work well for this. They are usually very accurately 50 ohms and can tolerate 100 watts (e.g. about 8 amps DC).
Maybe earlier in this thread, maybe somewhere else, I may have mentioned resolution, accuracy and scaling. In this case the meter to have the ability to measure large currents might be considerably insensitive at low currents. What does the manual give for lowest current range error? I don't see a manual on the Amazon listing.
Even "good" current clamps might have as much as 500mA offset (e.g. even at zero amps it will display 500mA) and ~100mA magnitude resolution (meaning it would show 500mA until you got to 600mA in this theoretical). These specs make them not much use below an amp or so.
To compare a $550 Fluke i1010 can do a similar full scale current (1000 A DC) as your 800A but it's only accurate to 2% +/- 0.5A so it's practical lower limit is 1A.
Very expensive (like $1k) lab probes can still have 30mA to 50mA offset making their use limited to only 100mA or more with any reliability at all in the measurement (even at this point you're in the 50% to 100% error range even with 10mA or less minimum resolution). Even "cheap" meters in this class are a couple hundred dollars with a practical limit of 500mA or more.
You will have to pay quite a bit to get one capable of around +/- 5mA or less in both offset and resolution along with low enough drift that you don't pull your hair out under 100mA. It's
very difficult to do non-contact current measurements this low.
If you expect less than 500mA you're better off checking with a shunt if you can, especially in the field and not in a lab setting, and below 100mA it's nearly mandatory to use a shunt, even in a lab. Outside a lab a sub 100mA capable clamp is going to be confused just by the Earth's magnetic field even if it had no internal error (which is itself related to how much it cost).
Just in case you're interested, a Fluke i30s is capable of being calibrated to do a measurement down to 30mA DC at 1% error +/- 2mA and costs $800 with an upper limit of 20A. It
may resolve down to 5mA but Fluke can't guarantee it so doing that is outside it's specs. So for this test based on what I see with the ARB even that Fluke may not be correct and would necessitate a shunt to verify anyway.
And for their part Tektronix is in the $2,000 or more range for a clamp-on current probe that will measure this correctly, but in fairness they're very concerned with doing so at high frequency (>50MHz up to GHz) so they're not going after the automotive DC parasitic market with their offerings.
If you can break the circuit and use a shunt resistor you achieve similar DC error for $10...
