Campbell Scientific SP10, SP10R, SP20, & SP20R Solar Panels - Manual (Page 14)

SP5, SP10, SP10R, SP20, and SP20R Solar Panels
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implies a bad solar panel, regulator, or cable. The magnitude of the voltage
output depends on the incident solar radiation.
5. Power Considerations
5.1 Solar Power and Lead Acid Batteries
The solar panel converts light energy to electricity, or specifically direct
current. The direct current produced is used as a charging source for 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 depends 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.
The battery supplies power directly to the operating system; the solar panel
supplies power to recharge the battery. The solar panel must provide at least as
much power to the battery as is being used by the system.
The battery must have enough capacity to power the system during times of no
charging (night) or low charging (stormy winter days).
5.2 Voltage Regulator
The solar panel must be regulated either with a Campbell Scientific regulator
or an attached regulator. The regulator has two basic functions: 1) blocking
any current flow from the battery to the solar panel, and 2) limiting the source
current to the battery.
The SP5 may be connected directly to the “Charge +” and “Charge ─”
terminals on the CR200(X) datalogger. Otherwise, the SP5 must be connected
to a Campbell Scientific PS100, PS200, CH100, or CH200 voltage regulator.
The SP10 and SP20 must be connected to a Campbell Scientific voltage
regulator. Campbell Scientific voltage regulators include the PS100, PS200,
CH100, CH200, and the voltage regulator integrated in the base of our
CR3000, CR5000, CR7, and CR9000(X) dataloggers.
The SP10R and SP20R have an on-board voltage regulator that connects
directly to a user-supplied flooded lead-acid battery such as a deep-cycle
marine or RV battery.