P4 fell out of sky "Broken Cell"

[Kartefour]

Was planning to take it up for a very quick flight, possibly the first time I didn't change the battery from the previous flight, started up, sounded a little off, landed it quickly, checked all the props, took off again, just hovered about 10 feet in the air listening to it (sounded fine) then it just shut off, and dropped right in front of me.
Happily, it landed on the soft dock directly in front of me and not in the the ocean. Broke the landing gear/strut and threw the battery out.

Had it flying right after without any problems.

logs show Cell 1 had a 0.5 volt deviation, and in the battery menu it recorded a "Cell broken" error message.

Battery is about two years old with 35 cycles...

Is there any chance the battery was loose? I will swear there was no gap showing between the battery and housing, but honestly I never tried pulling it out to see if it was secure, like I mentioned, one of the first times I've flown two flights on the same battery.
below is the last lines of the log:

Thanks for your input..

0m 28.9s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.6ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.5ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.1s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.5ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.2s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.5ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.3s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.4ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.5s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.4ft 85% 14.774V 3.333V 3.799V 3.825V 3.817V 0.492V
0m 29.6s P-GPS 13satellites 15.7ft 15.4ft 0.7mph 12.4ft 85% 14.774V 3.333V 3.799V 3.825V 3.817V 0.492V
0m 29.7s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.4ft 85% 14.774V 3.333V 3.799V 3.825V 3.817V 0.492V

 

[Fly Dawg]

0m 28.9s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.6ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.5ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.1s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.5ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.2s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.5ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.3s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.4ft 85% 14.897V 3.365V 3.834V 3.854V 3.844V 0.489V
0m 29.5s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.4ft 85% 14.774V 3.333V 3.799V 3.825V 3.817V 0.492V
0m 29.6s P-GPS 13satellites 15.7ft 15.4ft 0.7mph 12.4ft 85% 14.774V 3.333V 3.799V 3.825V 3.817V 0.492V
0m 29.7s P-GPS 13satellites 15.7ft 15.4ft 0mph 12.4ft 85% 14.774V 3.333V 3.799V 3.825V 3.817V 0.492V

Judging only from the Cell values you posted ( In Bold ) it appears that cell 1 has an issue. 3.2v is the absolute cutoff point per cell.

 

[Kartefour]

Thanks,
I'm thinking I'll just retire that battery. I got lucky once, why chance it again. I Discharged battery and recharged, cells are all normal and within spec voltages.

Strange.

Thanks

 

[Techguy56]

I don’t think the battery was in all the way since it popped out after hitting the dock at only 10 feet.
Just my theory.

 

[Fly Dawg]

I don’t think the battery was in all the way since it popped out after hitting the dock at only 10 feet.

That is not unusual for the battery to pop out following a crash or very hard landing from most any altitude. The low cell voltage was the primary issue, regardless of the battery being ejected or not.

 

[Techguy56]

That is not unusual for the battery to pop out following a crash or very hard landing from most any altitude. The low cell voltage was the primary issue, regardless of the battery being ejected or not.

I know the low cell voltage was the primary issue. I first thought if the battery was not completely seated maybe it could give false readings which was I said Just my theory, rather than sounding like I know it all.

 

[Fly Dawg]

I first thought if the battery was not completely seated maybe it could give false readings which was I said Just my theory, rather than sounding like I know it all.

You weren't sounding that way at all. Was just clarifying the fact of the cell values. I would have like to have taken a look at the entire log file, although in this instance it was not really necessary. In regard to the "false" readings, of all the data files I have reviewed, I have never seen such an occurrence, and if this were the case, the FC would have shut the AC down anyway, basically with the same results.