Panasonic WX-SZ200P Operating Instructions Manual page 17

Also refer to the microphone manual.
The microphone cannot be used while in charging.
Important
Microphones will not be charged if they are not correctly set on the
charger.
If the charger cannot directly contact the
microphone because of an obstruction, the
[ERROR] indicator on the charger will either
light up or blink. Failing to remove the
obstruction may cause overheating.
Remove any foreign matter which may be
causing the obstruction.
Set the power switch on the microphone to OFF while charging. Even
when you insert the microphone into the charger with the power switch in
ON position, the microphone is automatically turned OFF and the battery
will be charged. However, in such event, you still need to move the
power switch to the OFF position. (This is because the battery power will
be slightly consumed after charging when the switch is in ON position.)
Hold the charger with your hand when removing a microphone from it.
In order to avoid battery capacity reduction due to self-discharge, the charger
will continue to pass minute current to the microphones even after the [CHG]
indicator on the microphone has gone off. The [CHG] indicator on the charger
will not light up unless the charger itself is powered OFF and then ON again.
If the [CHG] indicator does not light up despite a microphone being inserted
into the charger, confirm that all the links between charger, AC adaptor,
power cable, and electric outlet are securely connected.
The charging time depends on the battery type and the specific use
situation, but at longest it will be around eight hours.
Charging the batteries outside of their operating temperature range may
substantially increase the amount of time required for charging.
Even if the batteries are within their operating temperature range, charging
while the microphone is very hot or cold may increase the amount of time
required for charging.
Both the microphone and the charger heat up during charging, but this is not
due to a malfunction.
Do not try to charge already full batteries. Doing so will reduce the lifespan
of the batteries.
Charge error indicator
17