MM2 Battery Storage in Hub & Battery Discharge (or Hibernation)

[LeafPeeper]

Bought a Mini 2 on the day it was announced, fully charged all the batteries and flew them the next day - down to around 60-70% for storage. Having had lots of DJI drones over the years and having read the plethora of threads and opinions on battery storage, that's what I generally do. Haven't flown it since Nov for a variety of reasons. Pulled out the MM2 battery hub today and noticed that all the batteries have only one solid LED when I hit the power button. I've read the manual and most of the battery threads in these forums, but maybe I missed something.

1. Is it safe to store the MM2 batteries in the hub (no charger connected), or will it discharge the batteries over time?
2. I know the MM2 batteries are supposed to auto discharge to 72% - but seeing them with only one LED bothers me. Did they auto-discharge all the way or does hibernation kick in based on storage time? (I know hibernation mode kicks in when the levels drop to 10%, but that shouldn't have happened here...)

Just wondering if I have a problem here. Attempting to charge them all now as I type this...

Any thoughts welcome...
LP

 

[old man mavic]

i find that both my MPP and MM batteries will over time discharge very slowly ,thats why its best to check them every two weeks or so ,i will recharge them once they get to one light solid and one flashing ,if i have not flown for a while i find its better to fully charge them and then discharge them back to three lights solid for storage ,my MM ones dont have a self discharge function so i just discharge them one at a time in the hub using my phone as a load i have a home made discharger for my MPP ones that consists of a 55w car bulb the type used in fog lamps and i used the cable cut from the car charger that came with the flymore combo as i never use it in my car the load is perfect and does not damage the battery ,my main reason for fully charging them is,because the cell balancing part of the charge cycle, takes place near the end of the charging process and if i wait till the cycle has finished then i know that they have the same voltage which is important when they are in use

 

[LeafPeeper]

Thanks for the feedback. I guess it surprises me because the two other drones I have left (Mavic Pro 1 and Autel Evo) both can go MANY months with no change in battery level once I discharge them to what I consider 'storage' level. I knew that even LiPo or Li Ion batteries had a self discharge rate, but I've always found it to be MUCH MUCH lower than older techs like NimH or NiCad. Seems wrong for my MM2 batteries to go from 70% to 10% over the course of 2 months.

LP

 

[Yeunglings]

I cant say for certain because I haven't seen any technical information on the hub nor cracked it open but I'm going on past experience of leaving battery packs plugged in to their chargers when not plugged in to the wall that they will drain off quicker than if left on their own, totally unplugged; probably due to AC to DC inverter in the wall wart and the hub shouldn't have one but with the intelligent charging capability to read and then charge the fullest battery first, maybe that is performing a similar function? And I wouldn't be surprised if having a battery inside the drone would do something similar.

 

[reaperman]

Im curious myself. I recently bought the MM2 in the dead of the winter. I've been using the same battery when I occasionally fly. The other two batteries have zero charges on them and have never been used. My thinking is they should be in a hibernated state from the factory and shouldn't need charging whatsoever until I decide to use them for the first time. ???

 

[hooah09]

Im curious myself. I recently bought the MM2 in the dead of the winter. I've been using the same battery when I occasionally fly. The other two batteries have zero charges on them and have never been used. My thinking is they should be in a hibernated state from the factory and shouldn't need charging whatsoever until I decide to use them for the first time. ???

If they were my batteries, I probably would not leave them in hibernated (nearly-depleted) state. Charge them up to ideal storage capacity (72% I believe) and store them that way. Regardless, if it were me, I would rotate through all of your batteries instead of just using one over and over again. I like to keep my batteries with a roughly equal number of discharge cycles between them.

 

[Yeunglings]

If they were my batteries, I probably would not leave them in hibernated (nearly-depleted) state. Charge them up to ideal storage capacity (72% I believe) and store them that way. Regardless, if it were me, I would rotate through all of your batteries instead of just using one over and over again. I like to keep my batteries with a roughly equal number of discharge cycles between them.

I was thinking the same thing about keeping all of the batteries "in sync" because thats what I try do with all of mine. There are pros and cons to both theories I guess. My way means that I shouldn't have to worry about a battery failing for, in this case, about 3 times longer( maybe more depending on how much time is allowed to cool off before recharging and maybe the feeling of needing to go to 0% because you only have the 1 battery charged) because they are all getting the same workout. The flipside is that all of the batteries will start failing around the same time frame so now instead of 1 $55 battery to replace in 6 months to a year it's 1 now, another in maybe a month or so and possibly the 3rd a month later. Everyone's flying and charging styles/ preferences are different and no 2 batteries are truly identical so that's not necessarily what's going to happen but it is something to think about. When I bought my 4th MA2 battery I found myself flying that one a little harder, longer and more frequently to try and play catch up with the first three. Like flying batteries 1 and 4, recharging 4, then 2 and 4, recharging 4 and so on and so on until it was almost in line with the rest. Maybe I flew and charged number 4 too much more and potentially shortened its life. So when I realized it I slowed down the process, allowing them all the opportunity calm down so to speak.

 

[lensimages]

Don’t think the update fix for battery storage in hub works, update my firmware last week on all three batteries, again stored the in the hub checked today, flew and recharged batteries on the 19th this month, all three are still showing 4 lights that is a week later stored in hub, any idea. Running Latest firmware , cheers Len

 

[MarkusAtHome]

After updating the FW, I have noticed no difference regarding the discharge behavior of the batteries when stored in the hub. Therefore, I continue not soring the batteries in the hub.

 

[brew99]

I haven't tried this process since updating the firmware to newest, but the manual suggests that it takes 9 days to get to the 72%. If you even push the button on the charge hub to check the status at anytime, it apparently resets the clock. Your experiment of a week might not have been long enough.

 

[teccer]

After updating the FW, I have noticed no difference regarding the discharge behavior of the batteries when stored in the hub. Therefore, I continue not soring the batteries in the hub.

I fully charged 1 of my batteries then left it in the hub and after 12-14 days it had gone down to 3 lights this is after updating the firmware

 

[MarkusAtHome]

I fully charged 1 of my batteries then left it in the hub and after 12-14 days it had gone down to 3 lights this is after updating the firmware

Great! I will give it an other try!

 

[Ashjuk]

I fully charged 1 of my batteries then left it in the hub and after 12-14 days it had gone down to 3 lights this is after updating the firmware

Mine too. I fully charged all of my batteries and left them in the hub. When I checked them over a fortnight later all three were showing only three lights.

The firmware update seems to have solved the auto-discharge problem.

 

[teccer]

Mine too. I fully charged all of my batteries and left them in the hub. When I checked them over a fortnight later all three were showing only three lights.

The firmware update seems to have solved the auto-discharge problem.

I've just found that after downloading the latest firmware not only do the batteries self discharge when in the hub but they will also discharge out of the hub as well.