Mini 2 Batteries won't discharge

[stef0083]

Hi fellow pilots,

I am completely new to drones, bought the mini 2 without thinking much about it and was more or less learning everything about it while flying and reading, watching videos about it. Of course i managed to crash it after 2 weeks and the exchange model should arrive within a few days. As for my issue, i kept the 3 batteries in the charging port (fly more combo) and noted that they still havent discharged to a safe level for a week (the charging hub was in the bag and not connected). I found some threads about it here but these are pretty dated already. So by current information shouldn't they have discharged a bit by now and could that already be a problem in my case by now, like broken batteries? Is it wrong to store them in the hub? Will i have to discharge them manually everytime after i won't fly for more than 5 days?

Thanks a lot in advance!

 

[old man mavic]

@stef0083 what you need to do is have one of them in the hub plug a load into the USB port such as a phone or tablet and let the battery in the hub send some charge to the device till it has 2 solid and one flashing light showing ,then switch batteries and do the same till you have all three partially discharged ,i believe the Mimi 2 batteries do not self discharge the same as the MM dont either, they are not intelligent batteries as such

 

[vindibona1]

@stef0083 what you need to do is have one of them in the hub plug a load into the USB port such as a phone or tablet and let the battery in the hub send some charge to the device till it has 2 solid and one flashing light showing ,then switch batteries and do the same till you have all three partially discharged ,i believe the Mimi 2 batteries do not self discharge the same as the MM dont either, they are not intelligent batteries as such

I could be wrong, but I thought I read somewhere that the Mini 2 batteries were intelligent. I'll have to check on that.

Edit: Checked the above. I think the marketing description is kind of misleading. We think of DJI intelligent batteries as having a self discharging function. But the way it's stated, the "intelligence" is only monitoring the status of the battery in flight and does not self discharge like a Mavic 2 battery would. The wording is:

The heart of your drone, the Intelligent Flight Battery for Mini 2 from DJI provides the Mini 2 with enough power to fly for up to 31 minutes on a full charge. Their Intelligent Battery Management System actively monitors the battery's status and reports it in real time, always alerting you to its available power as you pilot the craft.

If discharge is ever needed the easiest way to do that is plug a device like a cell phone or tablet into the battery bank and let it charge from the battery bank, thus depleting the batteries.

 

[old man mavic]

the charging hub has two jobs charging and also discharging
as you have said it can also be used to charge other devices like a power bank ,that is ok to a point, but if you are using it for that purpose then in order for it to not take too much charge from each battery you need to remove two of the batteries and keep an eye on the lights
otherwise if you just left the three batteries in the hub, it would not start the second and third battery discharging till the previous battery was at around 20% ,which is to low for them to be stored for any amount of time ,

 

[stef0083]

Thank you all for the swift replies! Ok, then i also misunderstood since i thought the mini 2 batteries also autodischarge?

That's weirds since the FAQ appaerently says:

"Before storage, it is recommended to charge the battery to approximately 72%. It is recommended to charge and discharge the battery once every three months to improve battery performance. If the battery level is below 72%, it is recommended to charge it until it is 72% before storing. If the battery level is above 72%, the battery will discharge automatically after 5 days to 72%." (which didn't happen in my case)

I am discharging them right now one by one. So seven days fully charged could do any damage to them? Just a little anxious since they are quite pricy to exchange. I think i will use them for the next few months quite frequently though, so storage shouldn't matter that much, still would be nice if they had the functionality.

 

[ZippyDo]

According to manual they should self discharge, btw I have same problem.

 

[StantonZ]

According to manual they should self discharge, btw I have same problem.

Me thinks the manual does not equal reality, but that wouldn't be the first time that happened.
I'm not a Mini owner, but this would be an important feature absent vs other drones (like the MA2)...and seems to be supported by other postings in this thread.
Bottom line: store Lithium-based batteries ~50% SoC.

 

[old man mavic]

have been doing some research on the Mini2 batteries ,i apologise if i got it wrong regarding the self discharge feature ,i do not own a Mini2 only the original MM ,and those batteries do not self discharge ,i also noticed that it seems strange that the act of checking the charge level resets the time it takes for the auto discharge to start
i am fully aware that this happens with other mavics my MPP included ,but they have a built in set of lights to show battery levels
with regards to the Mini batteries ,they either have to be in the drone, or the charge hub to get a light display of remaining charge ,if i remove a battery from the hub and then replace it all the lights for the three batteries light up ,as they do if i press the charge level button on the hub ,so maybe this is resetting all the batteries self discharge time, so preventing them from starting the discharge process the only way to see if it is the issue, would be to leave one of the batteries out of the hub fully charged ,and after seven days feel if it is slightly warm ,which would mean it has started to discharge, then compare it to the other two in the hub

 

[Ashjuk]

This is from the DJI website -

How do I maintain DJI Mini 2 batteries?​

Before storage, it is recommended to charge the battery to approximately 72%. It is recommended to charge and discharge the battery once every three months to improve battery performance. If the battery level is below 72%, it is recommended to charge it until it is 72% before storing. If the battery level is above 72%, the battery will discharge automatically after 5 days to 72%.

I am currently in an on-line chat to DJI support about it -

"Dennis
I will check with our senior engineers and see what is the possible cause or solution for this"

They are going to email me with their response. I will let you know what they say.

 

[Mike Mas]

Generally speaking, it is not going to hurt any lithium battery to sit un-used for weeks or even up to months. Prior to smart batteries the only thing we did is not store them fully charged if the batteries are not going to be used for an extensive period of time. If you're putting your machine away for a season bring them down to 70-80 %. I still have all my Phantom 1 batteries and they are fine after thousands of charge and discharge cycles.

Mike

 

[Made2Phly]

the charging hub has two jobs charging and also discharging
as you have said it can also be used to charge other devices like a power bank ,that is ok to a point, but if you are using it for that purpose then in order for it to not take too much charge from each battery you need to remove two of the batteries and keep an eye on the lights
otherwise if you just left the three batteries in the hub, it would not start the second and third battery discharging till the previous battery was at around 20% ,which is to low for them to be stored for any amount of time ,

I am confused about “leave it on the charging hub“ to discharge. Do you mean leaving battery( ies) on the hub with the hub unplugged? Or is it with the charging hub unplugged and something connected to the USB port? If that is the case, I assume further that the USB output is produced by the batteries, rather than the hub being plugged in?

 

[Howard70]

I don’t store my six Mini 2 batteries in the hubs and I’m almost certain they self discharge after a period of time and then remain stable. It is sort of tricky to determine as I don’t have any means of determining if they’ve discharged or not without placing them in the hub or the drone!

Howard

 

[Marcass Carcass]

Smart batteries, who cares, I ALWAYS discharge to 65 to 70%, if I don't use all of my charged batts within a day....

 

[old man mavic]

@Made2Phly ,yes using the hub with a battery in to charge something else ,yes the USB outlet is the one that you use to charge ,from the hub to another item its a way of reducing the charge in the batteries instead of leaving them fully charged ,if you havent flown them for some reason ,and dont expect to be using them for some time

 

[Made2Phly]

@Made2Phly ,yes using the hub with a battery in to charge something else ,yes the USB outlet is the one that you use to charge ,from the hub to another item its a way of reducing the charge in the batteries instead of leaving them fully charged ,if you havent flown them for some reason ,and dont expect to be using them for some time

Thank you kindly. My confusion has dissipated.

 

[jweaver]

One thing i was surprised about using the charging hub to charge an external device is that it only draws current from one battery, rather than all in parallel.

So if you are going to use this technique to discharge the batteries, is the suggestion that you insert one into the hub at a time?

 

[Geeforce]

Wrote this somewhere else before. My batteries don't discharge to 72% within 5 days. just a few percent maybe. No matter if they are in the hub or not.

 

[old man mavic]

One thing i was surprised about using the charging hub to charge an external device is that it only draws current from one battery, rather than all in parallel.

So if you are going to use this technique to discharge the batteries, is the suggestion that you insert one into the hub at a time?

@jweaver yes what happens is if all the batteries are in the hub then it will discharge one to a very low amount before it moves on to the next one, and so on its similar to when the batteries are being charged in the hub, so you could if you have plenty of time to sit and watch the discharge process, just remove each battery when it has reached the level you need ,the only reason i say do it one at a time is in case you forget that the batteries are being discharged ,or you get called away and forget to stop the process ,at least if there is only one battery in the hub you are not reducing the charge in all of them
i have 4 batteries for each of my drones so sometimes i will just charge 2 of each if i am not going out for to long ,such as during the lockdown only local, and that way i know that with luck, and the weather staying dry i can have enough time to fly all 4

 

[stef0083]

This is from the DJI website -

How do I maintain DJI Mini 2 batteries?​

Before storage, it is recommended to charge the battery to approximately 72%. It is recommended to charge and discharge the battery once every three months to improve battery performance. If the battery level is below 72%, it is recommended to charge it until it is 72% before storing. If the battery level is above 72%, the battery will discharge automatically after 5 days to 72%.

I am currently in an on-line chat to DJI support about it -

"Dennis
I will check with our senior engineers and see what is the possible cause or solution for this"

They are going to email me with their response. I will let you know what they say.

I'm really interested what they'll say. It's not a dealbreaker for me but would be great if we wouldn't have to think about it all the time we take longer breaks om flying.

 

[reaperman]

Without some kind of way to test a batteries percentage other than putting into the drone and hooking everything up, its only a guess. I know if I charge my mm2 batteries and they sit idle for a few days, they will only show 3 lights when I put them into the charging hub. Which makes me think they discharge to the proper level by themselves.