KANOMAX 3900 Portable Particle Counter - Manual (Page 83)

7. Battery Charge 76
7. Battery Charge
7.1 Charging Battery
You cannot charge the battery when it is installed in the instrument.
Open the battery compartment cover on the rear of the
instrument. To open the cover turn the knob around 90
degrees. (Use a coin or something similar to turn it
easily.)
To disconnect the cable from the battery, hold the sides
of the cable connector as shown in the picture below and
remove the battery.
Connect the battery to the provided charger to recharge
the battery. It takes about 6 hours to charge the battery
fully.
After the battery is charged, install it into the instrument
reversing the above procedure.