User's Manual

Trimble R7/R8 GPS Receiver User Guide 45
General Operation 4
Trimble R7 GPS Receiver Operation
survey and operating conditions. Typically, one battery provides about
3.5 hours of power during an RTK survey using the internal radio, and
about 5 hours during a survey without the internal radio.
The external power source is always used in preference to the internal
batteries. When there is no external power source connected, or if the
external power supply fails, the internal batteries are used. The internal
batteries are drained in turn, and the receiver automatically switches to
the full battery when the first battery is drained.
If no external power is supplied and both internal batteries are drained,
none of the data that you have logged is lost. When internal or external
power is restored, the receiver restarts in the same state as when power
was lost. For example, if the receiver was logging data, the data file is
not corrupted, and when power is restored the receiver resumes
logging with the same settings as before.
The power supply that comes with the Trimble R7 receiver charges the
internal batteries while they are still in the receiver. To do this, connect
the power supply to the power/serial data cable, connect the cable to
Port 2 on the receiver and then connect the power supply to an AC
power source, as shown in Figure 4.2 on page 46.