Rev #2
Version 3.00
August 2020
Page 29 of 80
If you want a faster charge you must connect the NANO
4
to a power supply, wait for it to
boot up and then press the button to switch the unit off. In this mode all the NANO
4
functions (GPS, Bluetooth, Memory) are turned off and this will increase the charging speed.
In this mode the NANO
4
can be fully charged in approximately 6 hours. The screen is still on
but the backlight is off. It is still possible to monitor the level of charge. The level of charge
is also visible via the LED.
Sometimes it may appear that the NANO
4
battery level when connected to a
charger looks full. However, when you disconnect the power the battery level
drops to 90%. This is normal as the battery level indication is different when the
charger is connected from when it is disconnected. To fully charge the NANO
4
,
please continue charging for a few hours. In the fast charge mode this will take
less time. Charge current must drop close to 0 mA or you will see indication
FULL.
The battery is fully charged when FULL battery status is displayed. This status
appears when the current drops below 5 mA and the battery voltage is more than
4.20 V.
Temperature limitations for charging NANO
4
battery are: > 0
°C (32°F) and
< 50°C (122°F)
5.11
Calibration of the Battery
You can calibrate the battery in the following way.
1.
The NANO
4
must be fully charged.
2.
The NANO
4
is fully charged when the charge current drops below 5 mA, or there is a
message FULL.
3.
Disconnect the supply cable and leave the NANO
4
running until it shuts down due to
an empty battery.
To be certain that the NANO
4
is really in discharge mode, the Battery Status row
of the INFO page text will show "DIP", which means Discharge in Progress.
You can increase the speed of the discharge cycle if you turn on the Bluetooth
module, set up brightness of LCD to maximum and turn off the screen fade.
After this procedure the NANO
4
has measured its battery capacity and with the next charge
the indication will be more accurate.
The calibration of the battery is performed during the production of the NANO
4
. In case that
calibration data is wrong, a calibration cycle is necessary for a correct indication of the
charge level.
If the charge level does not show a correct value compared to the battery voltage
it is necessary to perform a battery calibration cycle. Example: Charge level: 99%
and measured voltage 3.6 V.