January, 2008
These plots show the whole month of January for both systems. January 5th was as bad as it ever gets in San Diego: dark and almost two inches of rain. For the TV system (#1), the total delivered solar energy is 8.116 kWh, while the system used 6.728 kWh. This implies a net battery and charging system efficiency of 83%. The battery dropped below 60% and 12 V during the early part of the month. The batteries in both systems were equalized on the 20th day of the month.
The lighting system (#2) taxes the battery far less than does the TV system, but also has a smaller (64 W) panel for replenishment. Partly because it does not use a maximum-power-point-tracking (MPPT) charge controller, this system seldom delivers more than 45 W of power to the battery. System #1, by contrast, uses an MPPT controller and often achieves 110 W (130 W panel).
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