Hello. I have to size a solar power system for a telemetry system. According to datasheets:
RF320 Current Drain
Rx Standby: 25 mA at 12.5 Vdc
Transmit: 5.0 W @ 12.5 Vdc < 1.2 A
Current: Active: <15 mA
Quiescent: <350 μA
But how long the system is going to be transmitting or active? There are beacons, hello's and neighbors in the PakBus network. How much overhead do they represent? The PakBus Networking Guide doesn't say anything about this.
Thanks for your help
Typically, in a telemetry network using the equipment you mention, auto-discovery and PakBus routing are not required. So I generally recommend setting the all Beacon intervals to zero and setting all the Verify intervals to the maximum value (18 hrs.). The duty cycle on the transmitter (the major power load) will be determined by your data collection method (One-way or Scheduled) and interval.
You can download an Excel spreadsheet form the CSI website (https://www.campbellsci.com/downloads?c=9999&d=315) that will help you to determine the solar panel and battery requirements for range of input variables.
Words of advice:
The spreadsheet does a very good job of calculating the minimum requirements based on your input, but it's only a design tool. In my experience, it is far better to oversize a solar power system than to undersize it. Use the spreadsheet to size you system and then make it one size larger. It will be cheaper in the long run when your power requirements unexpectedly change.
Dear Travis, thank you for your helpful comments.
We also have a video tutorial on using the power budget spreadsheet: