Battery query: How big or small a bulge before we stop using an MP battery?

[Balko]

I have noticed a slight bulge on the underneath of one of my MP batteries. It is unrecognizable if we just look at it. However, when I moved my finger on it’s surface, I noticed that there was a slight vertical bulge on the underneath side of my battery.
Should this already be replaced?
Voltage of the 3 cells varied by only .01v per cell.
Note: Battery was probably only 80%+ charged when picture was taken.

Hoping that our forum members would be able to give their advice on this important issue.

Would appreciate very much if “msinger” would be able to read this post and give his invaluable advice.

Thank you in advance.

*Picture attached

 

[ac0j]

I would say you should be OK for awhile. If you notice it getting worse, or if it becomes harder to lock into the Mavic than other batteries, discard it.

 

[DanMan32]

You actually have a 0.02v variance between first and 2nd cell. I am unable to see the bulge in the photo so it must be very slight. Could be for something other than a battery swelling. Be careful with that one and don't fly where you can't recover or might hit someone or vehicle should you have an abrupt power loss. If it behaves normally after several cycles and bulge doesn't get worse, it may be OK after all.

 

[Rick0504N]

When in doubt....

 

[Drone_guy]

When in doubt....

Whip it out?

 

[Kilrah]

Looks perfectly fine... If it bulges so as to be flush with casing then get rid of it.

 

[sparkorc]

As some of the others have said just keep your eye on it, and if it shows signs of getting worse then discard it, but from the photo I cant see any bulge or swelling on that battery.

 

[mnis]

My opinion:
I would like to know in advance whether there really was no use under 25 percent charge level, how old is the battery, how many charge cycles does it have, and from which period (10 to 1 days) the automatic discharge was basically set? In addition, it is interesting, whether there were repeated critical temperatures during use and storage of the battery?

Basically, every day with 100 percent charge is a bad day for LiHv batteries and also ordinary LiPo's!

The default setting for the automatic discharge of 10 days leads in the long term to premature battery fallout

I would examine this battery regularly (... cell voltages, cracks in the housing and deformations), and only use at low altitude and distance.

Important:
If an expansion is caused by chemical imbalance, then this always happens evenly and first in at least one (...usually weakest) battery cell. Under the black type plate is (...directly felt) only one of a total of 3 battery cells. That with the other 2 battery cells at some point maybe something is wrong, you usually notice only when it is too late and the battery case has begun to break slowly.

In short:
The swelling of a single battery cell is definitely critical. The battery pack should be disposed of immediately. However, if it is a punctually deformation under the type plate, then it could also be an insignificant irregularity (... caused during production).

 

[Balko]

My opinion:
I would like to know in advance whether there really was no use under 25 percent charge level, how old is the battery, how many charge cycles does it have, and from which period (10 to 1 days) the automatic discharge was basically set? In addition, it is interesting, whether there were repeated critical temperatures during use and storage of the battery?

The battery is more than a year old and had been charged less than 60 times. I did set it to automatic 10-day discharge but would usually not wait till the 10th day to discharge up to maybe the 80% level. There was once though that I felt the battery a bit warm to touch after about 8 days. And yes, I remember that there was a battery pack that was abnormally hotter than usual after a flight. Am just not so sure if this is the same battery pack



Basically, every day with 100 percent charge is a bad day for LiHv batteries and also ordinary LiPo's!

Noted.




The default setting for the automatic discharge of 10 days leads in the long term to premature battery fallout

I left mine on it’s default setting.




I would examine this battery regularly (... cell voltages, cracks in the housing and deformations), and only use at low altitude and distance.

Important:
If an expansion is caused by chemical imbalance, then this always happens evenly and first in at least one (...usually weakest) battery cell. Under the black type plate is (...directly felt) only one of a total of 3 battery cells. That with the other 2 battery cells at some point maybe something is wrong, you usually notice only when it is too late and the battery case has begun to break slowly.

The bulge I felt was vertically positioned, somewhat representing a third of the cells.



In short:
The swelling of a single battery cell is definitely critical. The battery pack should be disposed of immediately. However, if it is a punctually deformation under the type plate, then it could also be an insignificant irregularity (... caused during production).

Thank you so much, sir, your inputs and would really take these into serious consideration. May I have your FINAL observations to my responses?

FYI: My responses were incorporated to your reply, just in case you may have missed it. Thank you again.

 

[Balko]

However, if it is a punctually deformation under the type plate, then it could also be an insignificant irregularity (... caused during production).

“punctually deformation”, didn’t quite understand what this means?

 

[mnis]

I meant: A swollen battery is always deformed over its entire surface, similar to the balloon or airbag. At the center of the total area the swelling will be highest. And yes, you are welcome to use my remarks. I hope it is understandable and helpful enough, so that you can recognize a defective battery early.

 

[dbyantis]

I have noticed a slight bulge on the underneath of one of my MP batteries. It is unrecognizable if we just look at it. However, when I moved my finger on it’s surface, I noticed that there was a slight vertical bulge on the underneath side of my battery.
Should this already be replaced?
Voltage of the 3 cells varied by only .01v per cell.
Note: Battery was probably only 80%+ charged when picture was taken.

Hoping that our forum members would be able to give their advice on this important issue.

Would appreciate very much if “msinger” would be able to read this post and give his invaluable advice.

Thank you in advance.

*Picture attachedView attachment 53761

Since a battery fault can cause the drone to stop flying, plus if the swelling gets any larger it may compromise the clips holding the battery in place, I would avoid using it, but I am very conservative with the batteries used for drones. If you have others to use I would use them.

 

[Balko]

I meant: A swollen battery is always deformed over its entire surface, similar to the balloon or airbag. At the center of the total area the swelling will be highest. And yes, you are welcome to use my remarks. I hope it is understandable and helpful enough, so that you can recognize a defective battery early.

The bulge is just on one side while the remaining two-thirds of the black plate underneath was normally flat.

Btw, I tried flying using said battery starting with around 80% charge with a temperature of 23. I landed it at 47% charge remaining and the temp was 43degrees. Is this abnormally high for a short flight with not much acceleration?

I then took it for another flight to lower the battery charge for storage until I decide whether to discard it or not. I discharged battery until 36%...safe enough for storage?

I hope I’m not disturbing you so much with these questions. Quite delicate issue so I took it upon myself to ask...hope you don’t mind so much.

Thank you again!

 

[mnis]

The batteries are getting hot quite quickly, and after the first third of their capacity it can be noticeably warm. Near the last third, the batteries are hot. I guess inside, temperatures close to 60 degrees Celsius can happen. So I guess the lower the charge level, the faster the battery heats up. If you can hold the battery without a glove, then it should be no problem

Supplement:
I have five original batteries for my MP. All batteries are now over 1.5 years old and none has less than 95 percent of their original capacity. Each battery has between 25 and 40 charging cycles. So far, there were no particular abnormalities. This year (September / October) I bought two Powerextra batteries as a supplement. And I am positively surprised by these replicas. All batteries are set for automatic discharge after 24 hours. I charge my batteries regularly a few hours before the scheduled flight. If it is not possible to fly due to bad weather, but the next day promises better weather, then in the evening I reset the timers by pressing the power button once. In this way, sometimes I delay the automatic discharge. The battery capacity I usually measure after about 15 to 20 flights. For this I use a suitable charging cable, RC charger and a separate discharger. I mean the smart flight batteries can take care of themselves very well. Only I consider the default of the automatic discharge (10 days) for much too long. The batteries are great with RC chargers and currents from 0.5 to 4 amps and more charged. The batteries turn off reliably when falling below 9.9 volts (3x3.3V) and exceed 13.05 volts (3x4.35V). A safe alternative use of these batteries with other devices or small to medium RC models is easy to implement, if a suitable cable exists.

 

[mnis]

Always pay attention to battery warnings of the DJI app. It is better not to fly in Sport mode if you are using a suspicious battery. At best, never use Sport mode. And in windy situations, you better use a strong (new) battery. A battery can always fail spontaneously, even if it seemed just fine and received a lot of care. So what the hell ... Either for reasons of justified fear to stay on the ground or fly as safe as possible. It can not be completely without fears in the air, unless enough money for a new machine is available

 

[Balko]

The batteries are getting hot quite quickly, and after the first third of their capacity it can be noticeably warm. Near the last third, the batteries are hot. I guess inside, temperatures close to 60 degrees Celsius can happen. So I guess the lower the charge level, the faster the battery heats up. If you can hold the battery without a glove, then it should be no problem

Supplement:
I have five original batteries for my MP. All batteries are now over 1.5 years old and none has less than 95 percent of their original capacity. Each battery has between 25 and 40 charging cycles. So far, there were no particular abnormalities. This year (September / October) I bought two Powerextra batteries as a supplement. And I am positively surprised by these replicas. All batteries are set for automatic discharge after 24 hours. I charge my batteries regularly a few hours before the scheduled flight. If it is not possible to fly due to bad weather, but the next day promises better weather, then in the evening I reset the timers by pressing the power button once. In this way, sometimes I delay the automatic discharge. The battery capacity I usually measure after about 15 to 20 flights. For this I use a suitable charging cable, RC charger and a separate discharger. I mean the smart flight batteries can take care of themselves very well. Only I consider the default of the automatic discharge (10 days) for much too long. The batteries are great with RC chargers and currents from 0.5 to 4 amps and more charged. The batteries turn off reliably when falling below 9.9 volts (3x3.3V) and exceed 13.05 volts (3x4.35V). A safe alternative use of these batteries with other devices or small to medium RC models is easy to implement, if a suitable cable exists.

How many days did you set for your DJI batteries to auto-discharge? Up to how many percent is left when the auto-discharge feature is used...and how long would it take?
Is it better to just set the auto-discharge feature for maybe 2-days than the default of 10-days?

 

[Balko]

Supplement:
I have five original batteries for my MP. All batteries are now over 1.5 years old and none has less than 95 percent of their original capacity. Each battery has between 25 and 40 charging cycles. So far, there were no particular abnormalities. This year (September / October) I bought two Powerextra batteries as a supplement. And I am positively surprised by these replicas. All batteries are set for automatic discharge after 24 hours. I charge my batteries regularly a few hours before the scheduled flight. If it is not possible to fly due to bad weather, but the next day promises better weather, then in the evening I reset the timers by pressing the power button once. In this way, sometimes I delay the automatic discharge. The battery capacity I usually measure after about 15 to 20 flights.

Wow, that’s a lot of batteries! Is that for just one Mavic or would you happen to have a couple?

Since a battery fault can cause the drone to stop flying, plus if the swelling gets any larger it may compromise the clips holding the battery in place, I would avoid using it, but I am very conservative with the batteries used for drones. If you have others to use I would use them.

I’m also quite concerned about the possibility that it might start a fire or explosion. Do you think my fear is justifiable considering the condition of my battery?

 

[mnis]

Before answering your questions, allow me a little story. I would like to clear all doubts and fears for you, but there is no absolute assurance in using your Mavic Pro.

Even if you use a new battery every month and everything else seems to be in order, it can spontaneously end in disaster.

I flew only months later after buying my Mavic Pro "fly more bundle". Previously, I had watched too many horrible videos on Youtube. In the process I learned mainly what can be done wrong and what the fatal consequences are. With this knowledge in my luggage, I was terrified to fly my MP for several months.

For me, the Mavic Pro was a relatively expensive purchase. And I always knew that I could not immediately buy a new Mavic. In the time until the very first flight I bought good and unfortunately also bad accessories. In addition, I began to construct accessories for my own Mavic. And of course I learned everything necessary around this new hobby. OK, before DJi I occasionally flew with the Hubsan H501S, which was also a great time in retrospect.

At some point I had everything completely and the many interspersed beautiful aerial photographs, filmed by other Mavic pilots forced me more and more to independent action. One day it went out to a beautiful view, and everything went smoothly. It was almost a matter of course on this first day. Well, it was not perfect, because of my inner unrest I had my beginners problems with photography and video recordings. But with every successful flight, I gained a bit more confidence.

I think now less of all that might happen. Absolute mindfulness in dealing with all components and good battery care can minimize the risk of the worst scenarios. But the last doubt can not be erased.

Why do I have 7 batteries?
The reason is simple, because I prefer to travel to interesting locations by bike. And on the way, there is no way to re-charge. On tour I go with at least five full batteries, a sturdy case for the MP and a lot of accessories, and some food.

I'm not a pro regarding dji or battery technologies. But in relation to the latter, in many years I have acquired a great deal of theoretical and practical knowledge. There are just too many myths and much more well-intentioned tips around the many different battery technologies. A user can very quickly fall into total uncertainty and lose track of things.

The LiHv batteries of the Mavics:
What happens when modern LiHv's or even LiPo's go through thermally, that can be seen very well on Youtube. There are even a few videos that show what happens to a defective Mavic battery. It is mainly harmful smoke in large quantities. The tendency to burn is significantly lower. Even the much-mentioned exploding is little more than an unspectacular bursting.

Charge and store your batteries in protected and ventilated environments / containers. Always be present during the charging process. And observe all other safety instructions. You can not extinguish a thermally leaked lithium battery, it is getting hot and decompose with a lot of smoke. Suitable means for preventing the formation of a fire are glass granules or ordinary quartz sand. Water is absolutely unsuitable as extinguishing agent.

The swelling of a battery cell is roughly due to a chemical imbalance. Decisive is mainly a long-term storage in full condition. The time to swelling can be a few days to weeks, and depends on other factors such as temperature, charge level and processing quality.

The second cause is the capacitive drift apart of the single cells under load. The first depleted battery cell of a battery pack is brought into a critical state by the other cells with more residual capacity, which in turn results in a chemical imbalance.

That's why the call to land through the DJi Go app starts at the beginning of the last capacity third.

The closer you get to the lower capacity end of all battery cells, the greater the cell drift. Excessive ambient temperature during storage and use may also cause the battery to swell.

MP1 LiHv 11.4V 3830mAh battery (... theoretically NEW) in numbers:
Charging end = 13.05 volts (3x4.35V).
Shutdown and detection of over-voltage = 13.06 volts. No-load voltage = 12.60 volts (3x4.20V) / 100% ... 3830mAh. Storage Voltage = 11.67 volts (3x3.89V) / 60% ... 2330mAh. Discharge end = 9.90 volts (3x3.30V) / 00% ... 0000mAh.

As soon as even one battery cell falls below 3.30 volts, the entire battery pack is shut down. So it is not waiting for the remaining battery cells reach the same level.

Thus, the weakest battery cell determines the maximum capacity of the entire battery pack.

After a full discharge, the voltage at idle increases slightly again, and 10.5 volts (3x3.50V) should be measurable.

Assuming you use the standard charger (13.05V / max 3.8A) and charge a battery that has storage voltage:
From 60 to 87% (...equals approximately + 1000mAh) Charge status lasts approximately 16 minutes and 30 seconds. Up to there is the maximum charging current (1C).
During the remaining 13% (500mAh) the charge current decreases continuously. The balancing charge takes place. At 21 minutes, this is the longest phase of the entire recharge process. And only when the battery at 13.05 volts takes about 100mA power charging is complete.

The filling of a stored battery from 60 to 100% takes about 37 minutes.

Calculated, a full charge 0 to 100% should last for no longer than 1 hour and 16 minutes. This coincides with my experiences.

Also:
A rechargeable battery with good condition hardly gets warm during the entire charging process when using the standard charger.
Basically, a so-called charger for MP batteries is not much more than a power supply, because the complete charging electronics and the balancer circuit stuck in any smart MP battery.

 

[dbyantis]

Wow, that’s a lot of batteries! Is that for just one Mavic or would you happen to have a couple?




I’m also quite concerned about the possibility that it might start a fire or explosion. Do you think my fear is justifiable considering the condition of my battery?

The only time I had a LiPo battery fire, it was while on charge, and NOT a DJI "smart" battery. So avoid adding any more energy to it. If concerned, appropriate disposal is not crazy.

 

[mnis]

The automatic discharge process runs slowly with little power down to 60%, it takes about 3 days. I do not remember exactly, but it gives enough time for quick reloading when needed. For my purposes, the start of the automatic discharge after 24 hours is sufficient.