A Minor Deviation™ is when one battery cell differs by more than 0.01 V and less than 0.07 V from the other cells in that battery.
Airdata™ presents this information in minor deviations per minute. The number of deviations per minute is calculated by dividing the total number of deviations per cell by flight time in minutes. When it comes to deviations, lower numbers are always better. A low number represents more balance between the individual cells. A high number represents less balance between the individual cells.
This is an example of a battery with very few minor deviations per minute.
In this example, Cell 2's voltage was at least 0.01 V different than the other cells six times per minute during this flight. This behavior is perfectly normal and is not a cause for concern.
This is an example of a battery with a moderate number of minor deviations per minute.
In this example, Cell 4's voltage was at least 0.01 V different than the other cells 59 times per minute during this flight. This behavior could be perfectly normal and is not yet a cause for concern. In this case, we would recommend monitoring this battery to watch for trends such as more deviations when flying in high winds or the effect the climate has on the battery's performance. If this battery is also experiencing Major Deviations™, we recommend monitoring it to ensure it does degrade.
NOTE: Even a perfect battery will have minor deviations, and this is considered perfectly normal. Factors such as wind, temperature, battery age, and battery condition all play a role in the battery's overall performance and lifespan. The deviation information is made available for you to monitor the overall health of your battery better and more efficiently.
WARNING: If you are prompted with any notification about a bad battery cell, a battery initialization failure, or any other battery-related error or alerts while in-flight, land the aircraft immediately, conduct a thorough post-flight check and assess the situation before using that battery again.