Just noticed in the manual fine print that the MM intelligent battery does not automatically discharge.

Comming from other DJI AC's I just automatically assumed that they would., now we'll need to manage them manually which is messy

This is something to keep an eye out for it if you want your batteries to last and reach the 300 cycles

Hi, thank you for reaching out and we do apologize for the inconvenience. The DJI Mavic Mini doesn't have the self-discharge feature the same as other DJI aircraft. However, I will take this as a suggestion of yours and will forward it to our designated department for attention. Thank you for your understanding and support!

How to manually discharge the batteries?

djiuser_aV50WkBDFZRt Posted at 12-29 05:12
How to manually discharge the batteries?

Flying the Mini, hovering indoors etc.

I use the hub that was included with the combo as a power bank to charge my phones and thereby deplete battery charge. The hub uses one battery at a time and stays with that battery until it is depleted, so you will want to pull the battery from the hub when it gets down to 3 or 2 LEDs.

djiuser_aV50WkBDFZRt Posted at 12-29 05:12
How to manually discharge the batteries?

If you have a combo just use to charge battery in phone etc .

Agree with Hallmark007 and Glenn, if you have a combo kit, just use the hub as a battery bank.

DowntownRDB Posted at 12-29 05:32
I use the hub that was included with the combo as a power bank to charge my phones and thereby deplete battery charge. The hub uses one battery at a time and stays with that battery until it is depleted, so you will want to pull the battery from the hub when it gets down to 3 or 2 LEDs.

Good idea!

Never thought of using the hub to manage the batteries. Very good idea. Thank you!

Traxx119 Posted at 2019-12-29 11:27
Never thought of using the hub to manage the batteries. Very good idea. Thank you!

What happens if you just leave the batteries charged?  
Would anybody like to hazard a guess at the number of hours or uses you might get.  
If 300 charges is the possible amount when carrying out careful management, what is that figure likely to be with less precise management?

DowntownRDB Posted at 2019-12-29 05:32
I use the hub that was included with the combo as a power bank to charge my phones and thereby deplete battery charge. The hub uses one battery at a time and stays with that battery until it is depleted, so you will want to pull the battery from the hub when it gets down to 3 or 2 LEDs.

Any chance one of you has let a battery "fully" discharge in the hub while powering another device? I'd be curious to know roughly what percent charge is remaining in a battery when it switches to drawing power from the next battery. I'm sure I'll get around to trying it myself sooner or later when the weather gets bad.

I'm guessing they didn't include this as a feature, but it would be extra convenient if the batteries in the hub would stop discharging when each battery reached about 40% since that's the bottom end of what is recommended for storing these batteries for longer periods.

Thanks for letting us know.

Dirty Bird Posted at 1-3 02:07
The Mini uses Lithium-ion batteries, not Li-Pos like the other DJI drones.  There is no need for an automatic discharge.

Your right you don't need to discharge li-po's for storage

But strangely, the manual on page 20, recommends the discharge.
It even mentions that MM batteries don't have the automatic discharge function
Not sure why DJI would include this if it did not have some bearing on the battery condition.

Some websites recommend discharging Li-ion to 40% for the best storage condition, supposedly prolongs battery life, but there are also a lot of other influencing factors in addition to the storage charge
https://zeusbatteryproducts.word ... s-in-home-business/

Mypinknee Posted at 1-2 07:42
What happens if you just leave the batteries charged?  
Would anybody like to hazard a guess at the number of hours or uses you might get.  
If 300 charges is the possible amount when carrying out careful management, what is that figure likely to be with less precise management?

Not sure what would happen to the Mini batteries if always left fully charged. I have been and will continue to discharge the batteries to around 50% if i'm not gonna fly for a week or more, because it says to do so in the manual.

Dirty Bird Posted at 1-3 02:07
The Mini uses Lithium-ion batteries, not Li-Pos like the other DJI drones.  There is no need for an automatic discharge.

Well done again him in the Hat...…… It is actually better as you can quickly grab your drone and the batteries are charged

It’s recommended that storing lit ion batteries to discharge to 40% and store at 60 degrees, batteries looked after correctly will outlast other batteries in both performance and life .

hallmark007 Posted at 1-4 02:28
It’s recommended that storing lit ion batteries to discharge to 40% and store at 60 degrees, batteries looked after correctly will outlast other batteries in both performance and life .

Couldn't agree more, that's why laptop manufacturers started to include utility that will keep battery charged only to 50% if you leave it plugged in all the time.

If you have some free time I find Battery University to have the best articles on all batteries but in particular Lithium-Ion.

For example they recommend storage as follows:  Store at 40% charge in cool place (40% SoC reads 3.75–3.80V/cell). Do not go below 2.0V/cell.

You can find a long, but good article on How to Prolong Lithium batteries here:  Prolonging Lithium Batteries

Here is the link to the Do's and Dont's, including storage, for Lithium batteries:  Lithium Dos and Donts

Has anyone done testing to show difference in Life-Span of batteries for a particular DJI drone when:
1) Taken care of by the book.
2) Sort of taken care of.  Occasionally left in charger and stored in warmer or colder environment.
3) Used and stored without concern.  

Unless there is a definitive difference between Life-Spans...

DowntownRDB Posted at 1-4 06:36
If you have some free time I find Battery University to have the best articles on all batteries but in particular Lithium-Ion.

For example they recommend storage as follows:  Store at 40% charge in cool place (40% SoC reads 3.75–3.80V/cell). Do not go below 2.0V/cell.

It’s great advice and comes from decent research , thanks for posting .

HedgeTrimmer Posted at 1-4 12:58
Has anyone done testing to show difference in Life-Span of batteries for a particular DJI drone when:
1) Taken care of by the book.
2) Sort of taken care of.  Occasionally left in charger and stored in warmer or colder environment.

Normally you only start worrying about it when a battery bulges or fails LOL

lannes Posted at 1-4 16:47
Normally you only start worrying about it when a battery bulges or fails LOL

There you go!  

A little of bit what I was wondering about.  How many extra days or cycles does going strictly by book get you over less stringent following of book?  

There is plenty of information about you should absolutely do "this", but little information about what doing "this" (worrying) gets you in better battery Life-span.

HedgeTrimmer Posted at 1-4 12:58
Has anyone done testing to show difference in Life-Span of batteries for a particular DJI drone when:
1) Taken care of by the book.
2) Sort of taken care of.  Occasionally left in charger and stored in warmer or colder environment.

I have Li-Pos for other drones that i've tried to take good care of ( storage charge, balanced cells, lipo bags etc..) and have had no problems. It's my first DJI drone and Lithium Ion batteries, so i'm gonna try to learn more about them. When a get a chance, i'll start by reading the 2 articles that DowntownRDB posted above.

HedgeTrimmer Posted at 1-4 18:10
There you go!  

A little of bit what I was wondering about.  How many extra days or cycles does going strictly by book get you over less stringent following of book?  

A major factor in all of this is the quality of the cells, even if we follow all the guidelines a battery could fail prematurely due to a bad cell or poorly quality one.


Knowing DJI, they would have sourced the cheapest practical cell (Samsung 18650-25R) to keep costs down.
The crazy thing is that these cost $3.50 each and DJI charge us $45 for the battery, so there is a bit of a price gouge going on even if you include the smart circuitry

It could be worse.  They could be selling ink jet printer ink!  ;)

Sigmo Posted at 1-4 18:39
It could be worse.  They could be selling ink jet printer ink!  ;)

I like the bit where they use some foam rubber on the front arms to fill up the gap which does not provide any structural support. The front arms actually twist quite easily at the motor join and along it's length, maybe causing prop strike, while the rear arms are all plastic and super stiff as a result. They would have done this to save weight

Traxx119 Posted at 1-4 00:34
Not sure what would happen to the Mini batteries if always left fully charged. I have been and will continue to discharge the batteries to around 50% if i'm not gonna fly for a week or more, because it says to do so in the manual.

After reading the articles posted by DowntownRDB, Iannes and a few others about Lithium-Ion batteries, i'm going to start using the recommended 40% not 50% when storing for extended periods. When the Mini spare batteries become available, i'm thinking about buying one , marking it, and keeping it fully charged at all times stored inside the drone, ready to go. It would be interesting to test it after six months, 1 year, 2 years, etc.. vs the other 3 cared for batteries to see if there would be any difference in performance.

and what happens if you leave the battery empty (at about 15/20%) - as at they should be at the end of a flight - for long period?
Any potential damage/less duration?

I had the question too, just the opposite ;-) After I always fly all 3 batteries empty, I charge all 3. Why should I now discharge the 100% charged batteries if I don't fly for 3 weeks or so and what happens if I don't. No answer so far, except "the battery should have between 45 and 60% charge", but that wasn't the question. And another open question : Why is the battery called an intelligent battery ?

jonny007 Posted at 1-7 09:02
I had the question too, just the opposite ;-) After I always fly all 3 batteries empty, I charge all 3. Why should I now discharge the 100% charged batteries if I don't fly for 3 weeks or so and what happens if I don't. No answer so far, except "the battery should have between 45 and 60% charge", but that wasn't the question. And another open question : Why is the battery called an intelligent battery ?

What we’re discussing here is one of the considerable difficulties faced when trying to make a successful electric car.
Batts  are now recommended to be charged only to 80 % for normal use whatever that is,  because charging to  100%  or  draining to less than about 25%  has a detrimental result on battery performance and life, as does rapid charging,  all of which adds to the , in my view, unsuitability of present battery technology for car propulsion.
As mentioned above, people want 100%  all the time, ready to go, which Is but one reason why  electric  cars fail to sell.
So, pay your money, and take your choice!

So what is the minimum charging level for storage mode? Is it confirmed about 40% (that should correspond to a Cell Voltage of about 3,5Volt

Sorry to insist on this argument but is a key point to maintain long battery life (or maybe DJI is more interested to have short live so they can sell more replacement? ;-)

Seriously.. can someone at DJI confirm the above?

and confirm also the following (based on my calculation based on logs.. maybe they are not correct)?
100% = 4,10v
75% = 3,77v
50% = 3,55v
40% = 3,50v
25% = 3,36v
10% = 3,10v

I ask about that because normally a storage Voltage for LiPo is about 3,8V per cell.. which in this case should correspond to more then 75%..

Waiting some clarification about that..

Thanks

spanzetta Posted at 1-7 11:56
So what is the minimum charging level for storage mode? Is it confirmed about 40% (that should correspond to a Cell Voltage of about 3,5Volt

Sorry to insist on this argument but is a key point to maintain long battery life (or maybe DJI is more interested to have short live so they can sell more replacement? ;-)

As per the Samsung 25R specifications

jonny007 Posted at 1-7 09:02
I had the question too, just the opposite ;-) After I always fly all 3 batteries empty, I charge all 3. Why should I now discharge the 100% charged batteries if I don't fly for 3 weeks or so and what happens if I don't. No answer so far, except "the battery should have between 45 and 60% charge", but that wasn't the question. And another open question : Why is the battery called an intelligent battery ?

When you fly all 3 batteries empty, just don't charge them to 100% until you are sure you will fly again soon. Just pull them out of the hub when it gets to 2 or 3 LEDs. Also, on days when you don't want to fly as long, you could also land the craft when battery level reaches 40% to 50%. Not sure if this makes a difference or not. It is suggested you may get longer battery life.

lannes Posted at 1-7 15:45
As per the Samsung 25R specifications

[view_image]

https://eu.nkon.nl/samsung-18650-inr18650-25r.html
3€ x 2 = 6€ and we pay 45€ ???
wow...

spanzetta Posted at 1-8 02:02
https://eu.nkon.nl/samsung-18650-inr18650-25r.html
3€ x 2 = 6€ and we pay 45€ ???
wow...

How else does DJI make a profit for it's owner

https://en.wikipedia.org/wiki/Frank_Wang

Traxx119 Posted at 1-7 16:02
When you fly all 3 batteries empty, just don't charge them to 100% until you are sure you will fly again soon. Just pull them out of the hub when it gets to 2 or 3 LEDs. Also, on days when you don't want to fly as long, you could also land the craft when battery level reaches 40% to 50%. Not sure if this makes a difference or not. It is suggested you may get longer battery life.

It's all too cumbersome for me, battery half full, full, discharged, charging, not overcharging, not undercharged, 40%, 65% .... then my batteries live a few days shorter ... it's ok. If I have charged the batteries 100% and then do not fly for a few weeks, they only have 40, 50 or 60% due to self-discharge. Optimal :-) I actually don't see any difficulties in replacing the battery cells when the life cycle ends and then you could use 3 to 4 € batteries as a replacement. I think there is no need to use only the original battery. Maybe 3rd party batteries will come soon. 50 € for a single battery is quite heavy.

jonny007 Posted at 1-8 09:21
It's all too cumbersome for me, battery half full, full, discharged, charging, not overcharging, not undercharged, 40%, 65% .... then my batteries live a few days shorter ... it's ok. If I have charged the batteries 100% and then do not fly for a few weeks, they only have 40, 50 or 60% due to self-discharge. Optimal :-) I actually don't see any difficulties in replacing the battery cells when the life cycle ends and then you could use 3 to 4 € batteries as a replacement. I think there is no need to use only the original battery. Maybe 3rd party batteries will come soon. 50 € for a single battery is quite heavy.

It can be a bit cumbersome at times. I guess Mini users will choose the method that works best for them. happy flying!

Unlike LiPos, regular lithium cells don’t become dangerous if stored fully charged or discharged to 0. Over time, they degrade in performance, taking longer to charge and running out sooner. At the end of its lifetime, the battery is not dangerous; it simply won’t hold a charge anymore. This degradation of the battery is accelerated by discharging to 0, storing fully charged, etc. But they are nowhere near as dangerous as LiPos.