Campbell Scientific SP70 Solar Panel - Manual (Page 19)

SP70 Solar Panel
For help in troubleshooting the solar panels, please contact Campbell Scientific,
Inc. Applications Engineers.
5. Power Considerations
5.1 Proper Solar Power and Lead Acid Battery Sizes
The solar panel converts light energy to electricity, or specifically to direct
current. The direct current produced is used to provide power to the system
and to charge lead acid batteries.
The solar panel operates in both direct and diffuse light (cloudy days), but not
at night.
The minimum battery size and solar panel output required depend on 1) the
average current drain of the system, 2) the maximum time the battery must supply
power to the system without being charged, and 3) the location of the site. When
some batteries are discharged below a specified voltage, the battery becomes
damaged and cannot be recharged.
On the average, the solar panel must be able to provide at least the amount of
power necessary to operate the system for 24 hours. This means that the solar
panels should not only be able to supply power to the system during the day,
but it should also be able to provide power necessary to charge the battery for
the power lost during the night. In addition, the battery must have enough
capacity to power the system during times of no charging (night) and a few
days of low charging (cloudy and stormy days). For additional help in
computing power budget for a specific system, please contact Campbell
Scientific, Inc. Applications Engineers.
5.2 Voltage Regulator
The regulator has two basic functions: 1) blocks any current flow from the battery
to the solar panel, and 2) limits the source current to the battery.
The Morningstar’s SunSaver SS-10-12V regulator can be purchased from CSI,
and it is not shipped with SP70 solar panel. The regulator connects to the battery
via the 15’ long 16AWG cable shipped with the regulator. The regulator and
battery should be housed in an environmental enclosure. Mounting brackets are
included with the regulator for attachment to an enclosure backplate.
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