Patent attributes
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.
