Testing of a battery with Z-low -- Keysight U1272A & U1273A multimeter

[Kiriakos GR]

Z-low this is a function of voltmeter which loads the AC/ DC line with one in parallel resistance, this causing a minimal current flow which is enough to eliminate mostly measured AC ghost voltages at not used wire pairs.

The second use of Z-low at DCV this could be testing of battery condition.
The point is that in all these years no one measured the actual current per voltage step, so us gaining awareness of what battery cells we can test with it.

My own recent engagement with a telescope and a red dot finder-scope, this it did bring me closer again to CR2032 coin cells and their electrical specifications’.
The drain current could start from 0.160mA so the LED to start glow, at 2.2V the LED gets full brightness by consuming 1mA and highest top current when the LED is saturated at 3V then this is 5.4mA
 
At my new Keysight U1272A benchmark, I did use my bench power supply among with the Fluke 8846A at it 400mA dedicated range.

And now here are the results.

1.50V ---- 0.83mA

3.00V----- 1.76mA

4.20V ----- 2.47mA

6.00V ----- 3.53mA

9.00V ----- 5.31mA

12.80V ----- 7.60mA

24.00V ----- 14.53mA

My findings are that at 1.5 & 3.0 DCV this load works best for coin batteries. 

At 4.20 DCV a lithium battery it can hardly consider 2.5mA as load.

Testing of 9V battery at 5.31mA this is close to real testing as this is the usual consumption of a handheld DMM. 

Now from 12V and up to 24V, I will assume that battery testing of small (stand-by) batteries it is possible, but such low current it can not considered as battery health indicator, except if you are dealing with severely damaged batteries.