Critical Battery

Owned by Matt Skelton
Last updated: Apr 04, 2023
1 min read

What triggered the failsafe?

The aircraft detected that the battery is reporting a battery percentage below the minimum threshold of 20%. This can be caused by:

Cause

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Cause

Info

Flying a large mission

The longer/larger the mission that is planned the more battery capacity is used. Long missions may use 80% or more of the battery capacity. 

Using a damaged or degraded battery

  • PHX battery capacity degrades over time. A battery that has been charged and discharged many times may deplete faster than a new battery.

  • Damaged (dented, puffy, punctured, or cracked) batteries may deplete faster than an undamaged battery due to the compromised state of the battery.

Obstructing the battery connection

In rare cases a false battery percentage can be reported by the battery. When this occurs the battery is often not fully seated into the battery bay or the battery bay is obstructed and causes a poor fit, which can cause an intermittent connection of the smart battery information to the autopilot. The autopilot interprets this as the battery reporting 1% charge and the failsafe is triggered.

What will the aircraft do?

At 30% battery the autopilot will send a low battery warning and the ground station will enunciate the warning and display a yellow warning message. after the 20% threshold has been met the aircraft will activate the Return To Land Flight mode and will perform the planned landing pattern. 

What should the pilot do?

The pilot should visually find the aircraft in the sky and keep eyes on the aircraft. Monitor the battery percentage remaining. Let the aircraft land and replace the empty battery with a full battery.Â