[HOW TO] Measure batteries on faltering battery powered devices!

Measure batteries on faltering battery powered devices!

When a battery powered device is faltering, there is only one good way to start debugging: measure the battery! An empty battery can cause the device to stop working but can also make some networks overload.
When a KaKu device f.e. has an (nearly) empty battery, the device will start shouting on the 433 band that the battery is low. The 433 band WILL overload which can cause other 433 devices to not reach Homey anymore.
I see peeps on the forum say “i did put in a new battery and it’s still not working” and “assuming the battery is new”. After a while they put in a new battery again and find out the “new battery” was not that new like they thought. Measure the battery is the only way to be sure the battery is ok!

Get yourself a multimeter

A digital multimeter is not that expensive. At Bol.com u can buy one for like 10 euros.
Like thisone here.
Mine looks like this:

Multimeter setup

  1. Connect the test leads
    Connect the supplied test leads to the multimeter. Read in the manual where these connections are on the meter.
  2. Set the multimeter
    If you have a 1.5 volt battery, you can set the meter to 2 volts. In some cases you can only choose 1,5V and 9V.
    Make sure you choose the correct setting. For measuring 3V batteries choose the 9V setting.
    It is important to know that a battery supplies DC voltage, so choose the DC symbol on the meter.
  3. Measure the voltage
    Put the battery down and make sure it is not moving. Hold the black test lead against the negative side and the red test lead against the plus side of the battery. You can now read the measurement on the multimeter.

When f.e. you need to measure a 3V battery you put the multimeter on the 9V battery position (see pic above) and put the 2 pins on the battery where red is the (+) and black will be the (-)
A new 3V battery f.e. should measure more then 3V like 3.22V or something like that.

As you can see in the above pic this new battery is 3.25V.

And this is not a new battery in the above pic.


This post is just to help other people with their Homey and Home automation. I am not saying a faulty device is always battery related.
Just saying that to measure the battery is the only way to know!


Love this! We had a huge box of batteries and i’ve checked them all, lots of them we’re empty apparently. Why they we’re in that box, nobody seems to know in this household.

Reason for this firstly was my sensor in the freezer didn’t report in anymore and pressing the button didn’t light up the led.

1 Like

Thanks! Came across this topic and thought why not buy a multimeter!

1 Like