Panasonic cordless phones use AAA-sized 1.56V Ni-MH rechargeable batteries . The phone does not measure battery strength by voltage but instead calculates battery strength by Use Time + Charge Time.
If your handset is indicating low charge and you replace the batteries with fully charged batteries, the handset will still show a low charge until it is placed in the charger for 6 Hrs (approx). If the batteries are fully charged as shown by the indicator and replaced with dead batteries, the handset may show the batteries are charged.
It is advised to keep the batteries in the unit and charge them until the handset is fully charged.
In addition, the following table explains the power on / off behavior and charging behavior when the handset is powered on or powered off.
To turn the handset power on or off, press and hold the power button for five seconds.
| Phone State: | Charger Response: |
| Power Off, battery not fully charged: | Charging LED indicator will go on, then turn off if batteries are already fully charged |
| Power Off, phone has full charge: | Charging LED indicator will go on, then turn off if batteries are already fully charged |
| Power On, phone has full charge: | Charging LED will not illuminate if batteries are fully charged |
To avoid damage, charge the battery only in temperatures ranging from 5 °C (41 °F) to 40 °C (104 °F).