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.
