Abstract: A backup electrical power unit for an alarm panel. The unit comprises a solar panel array which produces an array output DC voltage and a charging current for a battery through a first circuit at a first voltage level of the battery output voltage. This circuit disconnects the array output from the battery terminal output at a second battery voltage level. The charging current resumes when the battery output voltage is at or below the first voltage level. The backup unit also includes a second circuit interposed electrically, serially with the first circuit to disconnect the array output from the battery terminal output below a disconnect, voltage level. A circuit is provided for connecting the battery to the alarm panel when the primary power to the alarm panel is interrupted. Status indicators are provided.

Abstract: A backup electrical power unit for use in providing a backup power supply to an alarm panel when primary power to the alarm panel is interrupted. The backup unit comprises a solar panel array, including an array output, the array producing an array DC voltage and a charging current at the array output. It further includes a battery including a battery terminal output having a battery output voltage. A first circuit is included, interposed electrically between the array output and the battery terminal output, for electrically connecting the array output to the battery terminal output at a first voltage level of the battery output voltage.