3.Power Analysis

Depending on the hardware available your power distribution and consumption can be monitored and recorded within the log files created by APM:Copter

Where information is available the APM Log File Analyser will attempt to review this information and summarise it along with pointing out any issues found.

Also worth noting is that towards the top of the text based analysis are the fail safe settings for the flight being analysed, these are often a consideration when reviewing power issues. For example, they may help you understand why RTL was automatically activated or understand at what state the power system needs to be in to activate a particular Fail Safe.


If a Power Fail Safe is activated then it will be recorded in the logs and detail in the text based analysis like this:


In the above example the RTL was triggered by the Battery Fail Safe Error.

At the bottom of the text based analysis we can see a power summary.

I think most of the information in the power summary is self explanatory except perhaps Eff (mA/Min). This is the Overall Flight Efficiency and is measured as mA used per minute of flight, this is a first glance at understand the flight efficiency of a model.

For example, if we recorded 483.94 mA/min, this means we used 483.94mAh for each minute of flight. So we could calculate that if we had a 5000mAh battery and we wanted to fly that to 80% capacity then we would be able to use 4000aAh, 4000 / 483.94 = just over 8 minutes of flight time.

The APM Log analyser performs this calculation for you and provides warnings if you are over stretching the battery. Consider though, this information is only as accurate as your parameter settings, battery calibration along with the type of flight being analysed. Refer to the APM:Copter Wiki for more information: [http://copter.ardupilot.com/wiki/common-power-module-configuration-in-mission-planner/](Battery Calibration)

If flight efficiency is important to you then consider completing a Auto Mission where the same circuit is performed many times within the one mission, each time with the flight speed increase by a few meters per second. The analyser will break down this flight into Auto Mission steps and detail the efficiency for each of those steps /flight speeds. Using this method it is possible to understand your most efficient flight speed to be used for your RTL flight speed or can be used during missions to get you to a particular place in the most efficient manner.

NOTES: 1) For best results complete at least 30 seconds at each flight speed. 2) In the following example the flight speed is not changed.


For more detailed information, you can view the Power Analysis Graph.