Battery drop from 86% to 0% forcing landing.

[rizosplayz]

I've just had a heart attack when my MA battery dropped from 86% to 0% and forced landing in the middle of nowhere.
Moments before i had a message saying: Propulsion Limited To Preserve Battery Health and after that the battery dropped and forced landing.
The battery went up to 70C (158F) but the weather conditions where almost perfect...WTF? Can i trust the battery from now on? Can i trust MA?
Thanks God there was no people or water around...

 

[Thomas B]

Yes, but not that battery. ?still in warranty?

 

[rizosplayz]

Yes, but not that battery. ?still in warranty?

Nope!

 

[Thomas B]

Nope!

You may still be able to use it for some “ground work” on your bird though.

 

[Deleted member 93449]

How do the battery contacts and connections where the battery connects to the drone look?

 

[rizosplayz]

How do the battery contacts and connections where the battery connects to the drone look?

Perfect...I've ordered 2 new batteries already but i am still afraid if the next battery will behave like this in the future and i won't be so lucky...

 

[The Editor]

I've just had a heart attack when my MA battery dropped from 86% to 0% and forced landing in the middle of nowhere.
Moments before i had a message saying: Propulsion Limited To Preserve Battery Health and after that the battery dropped and forced landing.
The battery went up to 70C (158F) but the weather conditions where almost perfect...WTF? Can i trust the battery from now on? Can i trust MA?
Thanks God there was no people or water around...

How long had your battery been sitting before you used it for the flight?
was at 100% when you started the flight and freshly charged (within the preceeding 24hrs)?

 

[rizosplayz]

How long had your battery been sitting before you used it for the flight?
was at 100% when you started the flight and freshly charged (within the preceeding 24hrs)?

Τhe battery was idle at 50% for a week or more and i fully charge it 1 hour before flight...

 

[The Editor]

Τhe battery was idle at 50% for a week or more and i fully charge it 1 hour before flight...

OK - so it’s not that then. ?
Seems very much like a collapsed cell.

How many flights on that battery?

This is why I never fly by percentage - it’s pointless and inaccurate.

If you monitor the cell voltages whilst under load (airborne) you could be alerted to something like this by seeing a dip in voltage on one of the cells before disaster strikes.

 

[WithTheBirds]

Are you suggesting the depicted % is inaccurate in all circumstances or only for a pack that has been off the charger for a a day or so?

Like many of us I flew on voltages and timers for years and didn’t trust this new tech initially.

I now appreciate the time to empty and % remaining reported in flight is more reliable than any assessment that might be made from cell voltages. Aside from the fact LiION chemistry has a remarkably flat discharge curve to have any chance of estimating remaining capacity you need a relaxed no load reading.

Keeping an eye on cell balance is a good idea. Have no fear though- the remaining capacity and time to empty is usually within 1% or actual. To say the it is pointless and inaccurate might cause unnecessary concern. It is certainly more accurate than might be assessed from voltage readings.

 

[old man mavic]

give it one more charge and check the cell voltages in the app to see if any of them vary this will point to a possibly faulty cell but even if all is well i would be reluctant to fly with it again, give it a hour after charging to let the cells cool and give you a proper reading

 

[spamgnome]

I had this EXACT thing happen to me 3 weeks ago. I was down at 35% before it went to zero, but same thing...forced landing. I actually sent everything to DJI for analysis only to hear, "Battery bad. Replace." Mine was just two months out of warranty. Grrr. I would love to get the following data from your flight:
- battery date of manufacture
- # of charge cycles
- were you in Sport mode?
- an Airdata (www.airdata.com) link to your flight. (In my case, you can very clearly see when one cell collapsed)

 

[rizosplayz]

- battery date of manufacture = Jun 2018
- of charge cycles = 26
- were you in Sport mode? = YES
- an Airdata (www.airdata.com) link to your flight. - I am not familiar with the procedure

 

[old man mavic]

spot mode will surely show ou any fault in the battery because that is when the current draw is at its most

 

[spamgnome]

- battery date of manufacture = Jun 2018

VERY interesting. My battery was also made in June 2018. Wonder if it's just coincidence or not.

- of charge cycles = 26

Mine had 36 cycles

- were you in Sport mode? = YES

I was as well. I don't think I'm going to use Sport mode any more unless I'm very high up, and not over water. When it goes into the emergency landing cycle, you can still move laterally, so I want to be able to retrieve the drone when it lands.

- an Airdata (www.airdata.com) link to your flight. - I am not familiar with the procedure

Airdata is very useful! Go to site, create a FREE account, install the app on your phone that you use to fly. Whenever you want, you can sync the logs from your flights that are on your phone to Airdata where you can see the details of your flights, including the minute by minute voltages of all three battery cells. Looking forward to seeing the details!

 

[spamgnome]

spot mode will surely show ou any fault in the battery because that is when the current draw is at its most

For this reason, I'm not going to use Sport Mode any more...seems like asking for trouble if a cell is weak.

 

[rizosplayz]

Flight Data:

 

[spamgnome]

Very interesting. Similar as what happened to me, except you had 2 cells collapse on you simultaneously right at the 1:59 mark, which was about 20s after you went into Sport mode. How do your other batteries look across your various flights? Have you flown since on this battery?

 

[rizosplayz]

Very interesting. Similar as what happened to me, except you had 2 cells collapse on you simultaneously right at the 1:59 mark, which was about 20s after you went into Sport mode. How do your other batteries look across your various flights? Have you flown since on this battery?

Thanks, i couldn't understand the graph. I flew with this battery again indoor hovering from 100% to 0% without problems except the battery temp was at 70C pretty high...

 

[Meta4]

I've just had a heart attack when my MA battery dropped from 86% to 0% and forced landing in the middle of nowhere.
Moments before i had a message saying: Propulsion Limited To Preserve Battery Health and after that the battery dropped and forced landing.
The battery went up to 70C (158F) but the weather conditions where almost perfect...WTF? Can i trust the battery from now on? Can i trust MA?

Look closer at your battery and it shows a problem immediately you launched.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Thanks, i couldn't understand the graph. I flew with this battery again indoor hovering from 100% to 0% without problems except the battery temp was at 70C pretty high...

That graph shows a difference of ~0.5 volts between cell 1 and cells 2 & 3.