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Mini 2 batteries.

cheddar-man

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When I've finished flying, I re charge the battery in the drone and then put it in sequence (I have three batteries) in the multi battery pack.

Today when I came to fly I put the next battery in the drone and noticed it had lost one LEDs worth of charge. On checking the other two they had also lost the one LEDs worth of charge.

Is this normal?
 
When I've finished flying, I re charge the battery in the drone and then put it in sequence (I have three batteries) in the multi battery pack.

Today when I came to fly I put the next battery in the drone and noticed it had lost one LEDs worth of charge. On checking the other two they had also lost the one LEDs worth of charge.

Is this normal?
They auto discharge after a few days down to a storage level. This goes for just about all modern DJI batteries. If you aren't going to fly for a period of days then you are better off charging your batteries at 50-60% and only fully charge them before a day of flying. Otherwise you are wasting battery cycles and shortening their life.
 
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here is some information about it:
Curated by Stefano Colitti


about this question there are many conflicting opinions that most of the time not
they have a logical / cognitive basis but only what this adjective "intelligent"
suggests, then let's start from this adjective.
The definition of "intelligent" is linked to the ability to understand: man is an intelligent being, and this intelligence is the ability to process experiences and make decisions.
Intelligent is commonly said of an animal that shows a certain ability to understand
the acts and words of man, to learn certain behaviors, to coordinate their own
actions in relation to the surrounding environment etc.
In the specific case of DJI batteries, but not only, we cannot define them as intelligent,
but more correctly that they have been made with intelligence, so the adjective does not refer to the object but to their behavior which was thought of by those who designed them.
Now that we have clarified that the improper use of the adjective "intelligent" is a ploy
commercial, yes because to say that a pan is smart would suggest that she is capable of
make decisions about what we want to eat, leave the house, do the shopping and all
the rest until the final cooking of the food, but we know that this is not the case “at least until
today". Adding a preposition "with" in front of "intelligent" changes completely
perspective, yes, because even if an object is made with intelligence, we are the ones doing it
so that it does well what it was made for.
Returning to the batteries of the Mavi Mini and Mini 2, these have a memory chip inside them called Eeprom which is able to store small amounts of data that must be
kept in order to be processed. For example information relating to discharge cycles,
the date of manufacture, the temperature, the voltage of the cells and other information
which the drone firmware will then use to optimize the flight time.
Some DJI batteries, in particular high-end drones, in addition to storing the information mentioned above, are able to discharge after a certain period of time, because
inside them a device called "dummy load" has been inserted which is activated after a
certain period of inactivity time and as many of you know it is programmable through the dedicated application, in practice they have a programmable timer inside. I'm
intelligent? Or are we making them look like it? I would say the second, but now let's see
because it is not quite the same for the batteries of the Mavic Mini and Mini 2. Why the batteries
can be discharged, it is necessary that there is a structure inside them that allows the
dissipation of the heat produced by the discharge, a structure not present in the batteries of the Mavic
Mini and some of you will know that this is called the "joule" effect which we can summarize
without too many technicalities: "a body crossed by current heats up" and in this way the
- 2 -
Excess current is transformed into heat, allowing the discharge, what it produces
heat is the "dummy load".
But to do this you need more space than the size of the batteries of the small ones of the
DJI do not have, this to the advantage of the overall weight of the drone.
Some are provided on page 21, point 2 of the instruction manual for the Mini 2
brief information that I report translated and that we will then try to understand better:
Step 2. Auto Discharge Function: To avoid swelling, the battery automatically discharges to approximately 96% when idle for one day
and automatically discharges to about 72% when idle for five
days. It is normal to feel moderate heat emitted by the battery during
the discharge process.
As for the 96% value, it must be said that all batteries are lithium-ion ones
that LiPo are affected by the ambient temperature which involves +/- 10% of the charge value,
for example, heat is a factor that accelerates the chemical processes inside the batteries
allowing them to perform better as opposed to the cold which slows them down.
The 72% discharged car is produced by a small "dummy load", which, as reported in the manual, produces moderate heat during the discharge phase, but this discharge
this percentage is not used to keep the battery in "storage" in case it is not
we will use it for a long time, but to make it safe ie to avoid those chemical processes
which could make it dangerous.
In fact, on page 23 of the same manual, the DJI in addition to all the temperature values at which it is recommended to use the batteries etc. writes this:
It is recommended that the “intelligent” flight batteries be discharged to 30% or less during
transport or storage. This can be done by flying
the aircraft outdoors until the battery level is below 30%.
From what we have just read, we can say that more than smart batteries, DJI engineers have been intelligent, knowing full well that LiPo batteries have problems.
related to security and storage given their ability to supply large amounts of current
instantaneous, making sure to mitigate their danger as much as possible, even with other technical devices such as the interruption of the current flow after a certain time
when these are stored outside the Drone or multiple Battery Charger.
We now know that in addition to safety, these batteries offer "even the less experienced"
to avoid potentially serious accidents, if we want to make them last over time, it's us
and our intelligence which must provide for their discharge, in the manner recommended by the manual "by flying the aircraft outdoors until the battery level is below the
30%
 
I with my mini 2 usually fly with 3 batteries and almost always land after about 17/20 minutes with still a percentage higher than 30% (35% / 37%) in this way when I put the batteries at home I also have the batteries in deposit. Sometimes it happens to discharge the batteries more and once at home I charge them with the digital battery charger with display one battery at a time, reporting the accumulation voltage. if I'm not flying, I check this voltage every so often to keep it at that storage voltage. in this way I have never encountered any problems with my batteries. At least for now..
Honestly, I never leave my batteries 100% charged if not in use, I charge them the same day I go flying.
However it is normal for the battery to lose voltage (self-discharge) if not used, even the controller is identical if you notice.
 
"I charge them with the digital battery charger with display one battery at a time, reporting the accumulation voltage."

What digital charger do you use please???
 
Last edited:
Yes, page 21 has the whole rational for the discharging. That's why I'm glad I have a 115vac outlet in my van. I can charge on the go. As for swelling, my cell phone (Galaxy S7) started to swell a LOT. Had to replace the battery, even though it still seemed to work. Even though it ruined the case.
To keep the batteries of our smartphones at their best, charge with slow charge if it can be set to a maximum of 85% and do not discharge below 20% I recommend recharging around 40%. with this system the battery of my old samsung after 6 years still holds up very well.
 
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