The data displayed in the above graphs is generated by averaging the stage height of the canal flume once per minute over a period of one hour. The hourly average flow (or discharge) is then calculated by looking up the flow, based on stage height, in the station’s flume rating table.
Station power consists of 8 alkaline D-cells. Fully charged the battery pack is nominally 12V.
Fully discharged, the pack would be at 7.2V.
The datalogger continues to operate, and collect and store stage height data, at voltages as low as 7VDC.
The cellular modem will stop uploading hourly data when the battery pack voltage drops to about 9VDC.
You should change the batteries before the voltage drops below 9VDC to insure uninterrupted data transmission.