Inspire 1 Down Hard...looking for help

[mromansea]

Hi folks - tough day yesterday. Inspire 1 dropped out of the sky like a load of brick from 160'AGL. Gimble is fine, sensor is fine but the bird has seen better days.

Trying to figure out what happened - it was either a bird strike or a battery failure. Unfortunately MME doesn't provide voltage readings on the batteries. I also noticed that the log file seems to suggest that the bird never "landed". Which would seem to suggest that the battery just shut down.

Tried up loading the DAT file but too large. Any ideas on how I can figure this out?

 

[Bri Guy]

Sounds like the battery shut off.
Were you climbing at the time?
Did you get any warnings?
Did you check you battery via the app after you took off, were the cells yellow, green, red ??

What was the temp of the battery when you were flying it?

 

[Bruno28]

Were the batteries charged before flying? Or was it charger weeks ago and it says it's full via the LED?

 

[Aerial-Pixel]

Have you uploaded to airdata / healthydrones?

 

[mromansea]

So here's how it happened. Charged all the batteries the day before the flight and noticed they were taking a long time to charge. This unit was a rental so I'm always a bit cautious and the batteries just looked old, minor dings etc. That said, all the batteries came up (eventually) with 4 bars and the test flight I did the day before was clean.

Ran 3 patterns at the target site and swapped batteries once. On the final run (running flat and slow at 160' AGL) just after finishing data capture got a small "hiccup" - I swear I could hear it almost stutter - and then a single heartbeat and it went down. I was looking at the screen when it happened so at the time it wasn't entirely clear to me how exactly it happened. It happens extremely fast - if my math is right about 3 seconds at 50 meters. Anyway found the drone (it was in waste high grass so it was not easy...) and it was still essentially in one piece. Loosely held together but one piece. No blood, no feather, no dead birds nearby. No claw marks on the unit.

Got it back to the office, ran some diagnostics with MME (for trajectory flight telemetry) and CsvView (for voltage and motor speeds). It's definitely a battery failure. One of the cells starting to fail in increasingly large voltage sags. The adjacent cell tried to take up the slack but by the 3rd wave, not happening. Battery shut down. Log goes dead.

 

[Scoobywrx05]

Same thing happened to my v2 on a 35 time cycled t48. 5 or so minutes into flying, not even hard flying, battery temp normal,voltage at 4 volts a cell, 70 percent battery remaining. Screen went blank and watched it fall from 300 ft agl. Needless to say it's pretty much scrap now.