Campbell Scientific CR5000 Measurement and Control Module - Manual (Page 28)

Section 1. Installation and Maintenance
1-4
1.3.2 Low Profile CR5000
The low profile CR5000 option is not supplied with a battery base. See
Section 1.5 and 1.6 for external power connection considerations.
1.4 Solar Panels
Auxiliary photovoltaic power sources may be used to maintain charge on lead
acid batteries.
When selecting a solar panel, a rule-of-thumb is that on a stormy overcast day
the panel should provide enough charge to meet the system current drain
(assume 10% of average annual global radiation, kW/m
2 ). Specific site
information, if available, could strongly influence the solar panel selection.
For example, local effects such as mountain shadows, fog from valley
inversion, snow, ice, leaves, birds, etc. shading the panel should be considered.
Guidelines are available from the Solarex Corporation for solar panel selection
called "DESIGN AIDS FOR SMALL PV POWER SYSTEMS". It provides a
method for calculating solar panel size based on general site location and
system power requirements. If you need help in determining your system
power requirements contact Campbell Scientific's Marketing Department.
1.5 Direct Battery Connection to the CR5000 Wiring
Panel
Any clean, battery backed 11 to 16 VDC supply may be connected to the 12 V
and G connector terminals on the front panel. When connecting external
power to the CR5000, first, remove the green power connector from the
CR5000 front panel. Insert the positive 12 V lead into the right-most terminal
of the green connector. Insert the ground lead in the left terminal. Double
check polarity before plugging the green connector into the panel.
Diode protection exists so that an external battery can be connected to the green
G and 12 V power input connector, without loading or charging the internal
batteries. The CR5000 will draw current from the source with the largest
voltage. When power is connected through the front panel, switch control on
the standard CR5000 power supplies is by-passed (Figure 1.7-1).
1.6 Vehicle Power Supply Connections
1.6.1 CR5000 with Battery Base
The best way to power a CR5000 with battery base from a vehicle’s 12 V
power system is to use the DCDC18R to input the power to the CR5000’s
charger input (Figure 1.6-1). With this configuration the CR5000’s batteries
are charged when the vehicle power is available. When the vehicle’s voltage is
too low or off, the CR5000 is powered from its internal batteries.