Audi A4 2010 Battery Problem

Surely it means 2.5% of full scale, that's the normal meaning isn't it?

No, sorry, I'm talking rubbish! I obviously had my analogue hat on.

However I've never found my (several) clamp meters very useful at anything below an amp or so. They are always heavily influanced by the placement of the meter jaws around the wire and by the proximity (or otherwise) of other wires in the vicinity. In addition for DC you have to clear any initial offset, presumably due to local magnetic fields.

My UNI-T UT210E has a 2A range, resolution 1mA. Look at the manual, rather than the Specifications page which is general for several models.

With a split open USB cable plugged into a fully charged powerbank, it shows 4mA to run the display and backlight, dropping back to 0 when unplugged.

The clamp meter has a resolution of 10mA in the 60A range setting. Testing the accuracy with my current-limiting bench PSU and a normal DMM seems reasonably promising. With the PSU set to 100mA, the DMM reads 100mA and the clamp (mostly) says 0.11A. (mostly = the reading is not stable, so I took the most common reading)

On average every 3 weeks. Sometimes she'll sit idle for 4 weeks.

Usually, you just select the ground strap, which has all the return current in it.

Paul

That's often the problem with clamp meters down at that sort of current, as I was saying. :-)

The deeper the discharge, the more the wear and tear on the battery, which reduces it's capacity and life.

But they can be made more sensitive. By turning up the Hall (cc) current in the sensor.

On portable instruments, there isn't the power available to do that. If the instrument was lithium powered, you would have more room for cranking it up.

All I know is, the one I had in the lab, the sensor current was "constant current 350mA" and the current came from a bench supply (the gray HP bench supplies that put out up to 50 volts @ 500mA and they run CC or CV).

It doesn't matter what sense current level you run a Hall Probe, it's going to drift and it needs to be zeroed before you make a measurement. (Zeroed with the conductor out of the jaws.)

Paul