Measuring a battery outside a device does not make sense. It is possible that the multimeter shows 3 V, but when the battery is under load the electrical voltage drops significantly.
The voltage of the battery must be measured under load, theoretically when the sensor sends data to Homey.
There are special multimeters that simulate this situation. However, the adjustable loads are usually not suitable for such sensors.
But with electrical resistors you can build a test setup yourself. However, in order to get the correct measurement result, you need to know the electrical current (mA) that is generated while the sensor is awake and sent data. With this information you are able to make the right choice of electrical resistors, which are has to be connected in parallel to the measuring tips
I read somewhere that Z-Wave sensors powered by ER14250 (3,6 V) batteries have an electrical current of about 30-35 mA when they are awake and sent data. but I do not know if this is correct.
Attention!!!
The battery may only be measured for a short time under these conditions. When measuring the battery with an electrical resistor connected in parallel, the battery will be short-circuited.
