Sudden battery power loss.

[astroprojector]

Hi There.

I was wondering if someone can shed some light on why the battery on my Mavic 2 Pro lost power. It went from 52% to 0%. Luckily the drone landed safe in the area where I could recover it. I have not flown the drone for a while, but the battery, what it looks like had about 50% of the charge. The error is "Not Enough Force/ESC Error. I posted some of the information from the log below. Just wondering what happened.















I than charge the same battery to full and let the drone hoover until the battery drained to about 50% and it seems to be OK.

 

[Yorkshire_Pud]

You would probably be better served if you make the Airdata page of the first image shareable.
When was the battery of this flight charged?
Flying on an 'old' charge is not a good idea.

 

[Cafguy]

I was wondering if someone can shed some light on why the battery on my Mavic 2 Pro lost power. It went from 52% to 0%.

I have not flown the drone for a while, but the battery, what it looks like had about 50% of the charge.

 

[Meta4]

I was wondering if someone can shed some light on why the battery on my Mavic 2 Pro lost power. It went from 52% to 0%. Luckily the drone landed safe in the area where I could recover it. I have not flown the drone for a while, but the battery, what it looks like had about 50% of the charge. The error is "Not Enough Force/ESC Error. I posted some of the information from the log below. Just wondering what happened.

The old I-started-with-a-battery-that-hadn't-been-charged-for-ages-and-the-voltage-suddenly-dropped story.

What happened was that your battery had been sitting around discharging.
Because you didn't start with a freshly charged battery, the % indicator gave you a completely false idea of how much charge was in the battery - it was never at 52%.

If you look at the cell voltages, they will tell the story.

 

[RodPad]

@astroprojector,
You got lucky!

I seen posts, the battery had set for two days and well most of them did not make to ground level a safe speed.

Rod ..

 

[Herongate]

@RodPad, i am a new drone owner and I am wondering about your comment above about batteries that had sat for only 2 days and ended up crashing the drone. What are we supposed to do regarding batteries? Is it just a matter of ALWAYS topping them before flying? I had 2 batteries that had been sitting for 6 or 7 days but had 4 green bars. So should I top them off anyway Or risk damaging them Or crashing the drone?
i gather from these posts that these batteries are nothing like camera batteries, right?Thanks in advance for your reply.

 

[RodPad]

Regarding drones?
I'm mostly familiar with battery issues on the Phantom.
In general, the battery level can read more than what it actually has, until it has current draw.

These members are great, all above so far will correct me If I'm wrong.

Its been the same for all rechargeable battery's.

Anybody remember Ni-Cad, I still have some.

I will check back tomorrow.

Rod ..

 

[slup]

...I am wondering about your comment above about batteries that had sat for only 2 days and ended up crashing the drone.

In general, no lithium battery will cause a drone to crash just because it have been sitting fully charged for 2 days... the root cause would have been something entirely different.

...Is it just a matter of ALWAYS topping them before flying? I had 2 batteries that had been sitting for 6 or 7 days but had 4 green bars. So should I top them off anyway...

What can mess up a battery, making it unfit to power a drone is among many other thing's, a self discharge or DJI's auto discharge. When a total battery (consisting of several cells) is discharged it's crucial that the cells behave very much exactly the same otherwise the total battery quickly ends up with major cell deviations. When a battery is manufactured the cells are being matched to make them behave as equal as possible... but over time & use the initial smaller differences in cell behaviour becomes larger, and as amp draw always "prey" mostly on the weakest cell it can eventually get catastrophic, with one cell diving below 3.0V & crash & the rest remains well above.

So just leaving a battery fully charged during a handful days in it's self... will not make it prone to cell failures, the self discharge isn't so quick (other kinds of battery wear gradually occur over time though, which can shorten the useful service life). But nowadays nearly all DJI batteries are auto discharged down to around 96% after one or two days... then later down to about 60% after 10 days... this is what can cause a major cell deviation, the auto discharge doesn't balance the cells in the discharge process. So if one cell is somewhat weaker that the others, the unbalanced discharge can prey on that weaker cell & creating a large deviation.

So if you always fully charge the battery before use (which includes a cell balancing) you will mostly be safe.

You have some more regarding batteries here in these posts:

Disable forced landing

DJI Mavi Pro battery reset using CP2112 and DJI battery killer

 

[RodPad]

@slup
Thanks!

"In general, no lithium battery will cause a drone to crash just because it have been sitting fully charged for 2 days.."

Fully charged!

Thanks again!!

@Herongate
I never what to miss lead anybody.
That's why I ask for a backup.


There are awesome members here.
I think they all need a pay raise.

Rod ..

 

[BigAl07]

For those who aren't "LiPo Fluent" reading this . . .

Once a battery has been sitting for "A while" the Battery Level Indicator isn't reliable at all. The onboard algorithm deals with "normal" Charge/Discharge behaviors and isn't able to take into account the degradation etc of a battery that's been "sitting" for "a while". It has no way to know what internal issues are going on and when the battery is suddenly put under a high load those problems become apparent and the FC will try to get the aircraft on the ground under some type of power if possible. When you apply power to climb out etc is the most critical point for a questionable battery. You're asking the most from a battery that, most likely, can't handle mediocre power demands let alone "Climb Out" power.

This post has some excellent "Battery" info noted in it if you want to take a read:

Mini 4 pro plus battery storage

Good morning everybody. Looked around but couldn't find any info here. I just got my Mini 4 pro w/ plus batteries. I have everything updated and batteries charged. It's been 10 days, and the batteries self discharged to 3 solid green lights. Is the 10 days correct? and is 3 solid green lights...

mavicpilots.com

 

[Ooda]

I’ve had my Mavic Air 1 and M2P for 4 years now and I’ve bought 2 extra batteries for both within the last two years. Once the air’s battery showed fully charged, but once I started my flight, thankfully I only climbed 200ft about to go out and all of a sudden “critical low battery” reared its ugly face and it started to automatically descend and I was able to guide it back safely. I waited about 30 minutes and fully charged it and tried again to just ascend and hover to see how long it would last and it gave me 15 minutes. Long story but I’m wondering should I just recycle and get rid of that battery just to be safe? I’ve flown a few flights since without any issues. Maybe I will answer my own question and just buy new batteries lol. Thanks for reading.

 

[slup]

...battery showed fully charged, but once I started my flight, thankfully I only climbed 200ft about to go out and all of a sudden “critical low battery” reared its ugly face and it started to automatically descend

...Long story but I’m wondering should I just recycle and get rid of that battery just to be safe? I’ve flown a few flights since without any issues.

If that battery was freshly fully charged just close to this flight...

That battery had most probably developed a high internal resistance over the years & use (& maybe abuse?)... so when you ascended up to those 200ft the amp draw made the voltage dive & one or all cells went below 3.0V & triggered the critical low voltage auto landing, if it also was colder ambient temps (colder batteries always have higher internal resistance) that could have contributed.

You should really start to upload your flight logs to a free Airdata account & familiarize your self with how your batteries behave & which of them that regularly misbehaves & comes close to critical, when it comes to voltage drops & cell deviations... neither of these battery data will show from a simple visual inspection, instead the consequences will just surprise you during flight.

If any of the batteries turn out to regularly show major voltage drops with even moderate commands (for instance, usually only one or the other full ascend or horizontal flight... & not in Sport mode) & maybe gets worse in colder or really hot ambients, you should monitor that battery closely & use it with a sudden triggered critical low voltage auto landing in the back of your mind... or even only use it for desk purposes.

Below common battery data is always good to keep track on, they indicate wear & give signs of how much risk it is to use them for flight duty. Out from these you can in time take decisions about continue to use them for flight duty, only use them for desk duties or if you should dispose of them asap (if swelling, it should be disposed of immediately). AND... just to have it said, you can't draw any firm conclusions from a single flight... it's the trend that matters.

- Remaining capacity (will be noticed in real life out from the regular achieved flight time)
- Tendency to get major voltage drops during amp draw (will not show on the outside)
- Tendency to develop major cell deviations during use (will not show on the outside)
- Swelling due to internal gassing caused by a electrolyte decomposition (this can easily be seen on the outside)

 

[BigAl07]

I’ve had my Mavic Air 1 and M2P for 4 years now and I’ve bought 2 extra batteries for both within the last two years. Once the air’s battery showed fully charged, but once I started my flight, thankfully I only climbed 200ft about to go out and all of a sudden “critical low battery” reared its ugly face and it started to automatically descend and I was able to guide it back safely. I waited about 30 minutes and fully charged it and tried again to just ascend and hover to see how long it would last and it gave me 15 minutes. Long story but I’m wondering should I just recycle and get rid of that battery just to be safe? I’ve flown a few flights since without any issues. Maybe I will answer my own question and just buy new batteries lol. Thanks for reading.

That's a hard YES!!

 

[slup]

That's a hard YES!!

Think that is to over react, way to little info is known about the battery in question... if it's not swollen & if it's just a matter of high internal resistance or a tendency to develop larger cell deviations (hover time seems to be normal), it will work for checking settings or update firmware's at the desk.

If you, @Ooda don't want to take any chances regarding auto landings... just don't use it for flying & buy a new one for that..

 

[BigAl07]

Think that is to over react, way to little info is known about the battery in question... if it's not swollen & if it's just a matter of high internal resistance or a tendency to develop larger cell deviations (hover time seems to be normal), it will work for checking settings or update firmware's at the desk.

If you, @Ooda don't want to take any chances regarding auto landings... just don't use it for flying & buy a new one for that..

While I FULLY respect your input I do disagree with you just from my own personal use and from my own personal experience and because of the fact is we are giving TRUSTED advice to our members. Since the battery is a Single Failure Point, if it has given me ANY type of "Critical Fault" I take it out of flight service. I find it to be fairly reckless to continue using the battery for "flights" after such an event, UNLESS you have the means and knowledge to perform some battery performance/health tests. Short of that, the battery is immediately removed from service.

Keep in mind, we are literally suggesting someone "trust" our suggestions and go flying a battery that very likely could give similar or worse results going forward. This is suggesting risking the entire UAS to save, what $79 on a new battery. We have to take into account who we are speaking to and their technical capabilities going forward.

I would 100x out of 100x suggest the battery be discontinued because if I'm wrong, they get a new battery. If you suggest to keep flying and your advice is wrong, it could have a much different outcome than the one experienced by the OP.

 

[slup]

... I take it out of flight service. I find it to be fairly reckless to continue using the battery for "flights" after such an event.

Yeah, in that with using it for flight duty we agree fully... but as the OP said -"should I just recycle and get rid of that battery" it's not a clear yes IMHO... the battery may be too weak for high amp draw & therefore too risky to get up on height where a auto landing can surprise.

But if the battery isn't swollen, it can still be used for desk duties, voltage drops & cell deviations will not cause any harm to the drone standing powered on the desk & the battery will not go up in flames either... the drone will in worst case just turn off.