Battery Communication crash

[mjstott]

Hi All,

Whilst flying to perform a survey of a mine waste dump recently, our Mavic pro 2 just fell from the sky. The iPad simply showed 'aircraft disconnected' with a black screen. We managed to find the drone, thankfully just a few scuff marks and one broken prop as it landed in a bush to break the fall. All I can find in the flight log is "Battery Communication Error", with the battery useful time dropping from 1547 seconds to 0 in 0.1 seconds, everything else seems fine to me, but I may be missing something so any advice would be appreciated. The battery was checked visually and other than a scuff on the outer surface, it seems fine. It has since been charged and used in two test flights with no issues, so I am suspecting that the battery was not clipped in properly before the flight. The battery was found about 15m away from the aircraft, I don't know if it separated in the air or on impact, either way, we have ordered battery retention straps for all out Mavics. The pilot was using GSP for a pre-programmed flight using waypoints and he has about 620 hours flying experience (although mostly with Phantoms). Any advice that anyone can give factually based on the log would be appreciated as we had a similar incident with a Phantom Pro 4 only a week earlier (posted in the Phantom thread)!

Keep flying, keep safe!

 

[bigswifty]

A proper expert will be along shortly I expect, but in the meantime, if a crash was gentle enough to break one prop and just a few scuffs, it seems unlikely to me that the battery would have dislodged on impact and flown 15 metres away unless it fell down a slope or a cliff or something.

 

[slup]

None of the flight telematrics show anything abnormal, not in the end or earlier in the flight ... the battery voltage & current draw behave & everything looks normal. The chart below looks a bit messy but want to set focus on the odd behavior coming from the battery signals at 103sec into the flight (from where the markers is placed in the chart), just 5sec before the log ends. All that data flat-lines & remain constant, then just in the end the useful battery time goes to zero. (Can't find the "Battery Communication Error" in the log ... did you see that else where?)

All looks like a sudden power loss ... not in general a uncommon problem for the M2 series unfortunately. The only thing that deviate from a usual battery disconnect is that your AC didn't make any abrupt motions when it happened, that's usually how & why the battery gets thrown out when it gets swollen during flight & pushing outward putting pressure on the latches.

Perhaps something more is shown in the mobile device DAT log during those last 5sec ... the one that belongs to this flight have FLY097.DAT in the end.

(Click on the chart to make it larger)

 

[peterc4]

Mine done exactly the same in April but was at 500 foot and 1500 foot away never seen it again this same problem just keeps cropping up here to regular to be coincidense

 

[Paul2660]

If you are worried about a battery dislodging, due to sudden stops, motions, severe flight movement etc. I would strongly consider something like this:

Amazon.com: 5 Pack 16mm x 300mm HD Rubberized Battery Straps Non-Slip - Apex RC Products #3021: Home Audio & Theater

Amazon.com: 5 Pack 16mm x 300mm HD Rubberized Battery Straps Non-Slip - Apex RC Products #3021: Home Audio & Theater

www.amazon.com

I use these daily, never have had any issues with straps coming loose in flight, and always are tight. Battery will not come out, even if it swells during flight. These straps are designed for RC planes and have a great rubberized grip.

Very inexpensive solution to a possible expensive loss.

Paul C