Use this battery tester to check 1.5 volt batteries like those your micro:bit uses!
Connect alligator clips or wires to GND and pin 1 of the micro:bit. Touch the wire connected to GND to the – end of the battery and the other wire to the + end.
CC BY-SA 4.0
v2.0
The read analog pin block senses voltage. A new battery outputs about 1.6 volts, which reports about 520. Even a dead battery outputs about 0.9 volts, which reports 290. Use this script to see the number from the read analog pin block.
Libraries:
micro:bit | Battery Tester
Avoid damaging your micro:bit!
test only 1.5 volt batteries
(D, C, AA, or AAA).
LED Display