Operating instructions

5100 ES Models II/III Portable Radio Operating Manual April 2009 3-9
Battery and Accessory Connector Section 3 - General Operation
3.4.2 Low Battery Indication
Note If the radio contains encryption keys and is not programmed for infinite key retention, be
sure to reattach a battery within approximately 30 seconds to prevent the loss of these
keys (see following).
A low-battery condition is indicated by the icon in the display. The battery should be
recharged or replaced as soon after this indication appears. Once this indication appears, it
stays on until power is cycled.
Note The signal strength indicator normally occupies the location used by the Low Battery
icon. If the radio enters low batty mode, the Low Battery icon takes priority.
The following additional low battery indications and conditions may be enabled by
programming:
• A chirp sounds once a minute in the receive standby and transmit modes.
• A chirp sounds each time the PTT switch is pressed.
• The top panel LED indicator flashes red every 30 seconds in the receive mode.
• Low power is selected when transmitting.
As indicated in the preceding note, the radio may need to be connected to a constant power
source to preserve the encryption keys in memory. This is required if “infinite key
retention” is not programmed. To allow the battery to be changed without losing the keys
with this feature disabled, storage capacitors maintain the supply voltage to memory for
approximately 30 seconds without a battery attached. Therefore, be sure to reattach a
battery within that time. Refer to Section 8 for more information on encryption keys.
There is a battery saver feature that can be enabled by programming. This feature
functions on trunked channels, and it automatically selects low transmit power when the
receive signal strength (RSSI) indicates that the site is nearby.
3.4.3 Battery Charging
Note When a battery is charged while attached to the radio, make sure radio power is off (see
following).
The battery can be charged separately or while attached to the radio. When it is charged
while attached to the radio, radio power should be turned off. If it is not, the battery begins
slowly discharging when the charger enters the trickle charge mode. This mode is
indicated by a green Ready indication, and it is entered automatically when the battery is
nearly fully charged. Gradual discharging occurs in the trickle mode because the charge
current is less than the radio standby current (of approximately 200 mA).