@hondarc3012r the link in the first post here is only available to Full Members of Grey Arrows Drone Club.
Details of how you can become a full member can be found here: FAQ - Grey Arrows Drone Club UK
Just a reminder of the Drone Service and Battery Maintenance guides that are available to Full Members.
A lot of you aren’t able to get out at the moment due to lockdown restrictions, weather, etc.
Making now the ideal time to service your drone and perform some battery maintenance 
Grab a 
, pull up a chair, have a read here.
Quick show of hands… do any of you perform any of this maintenance on your drone, or your batteries?
Either intermittently throughout the year, or at regular intervals?
Just curious 
Yep, I do 
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My experience has been filled with contradictions.
Back when I bought my first Phantom1 I purchased a shed load of the ubiquitous Turnigy 2200mAh 3s packs. I’ve cared for them much like a crack addicted whoring negligent parent. In those eight years I’ve only had one die on me when one of the three cells failed.
In contrast I bought a new smart battery for one of my more obscure drones. I treated this battery with great care. I only used it twice and each time it was put away with the correct storage charge. A few months after the second flight I returned to it with the intention of charging for a flight and… it had swollen so much the plastic case had completely spit in two and the PCB of the smart circuit had cracked.
There is a science to LiPo’s but sometimes they can belie rhyme or reason.
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Me too.
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I need to become a full member to read this document shame ah well only an excuse to spend more time reading posts 
Which just happened after I wrote this wow 
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Me: My M2P batteries really aren’t holding their charge well at all. I only charged them 2 days ago and they’re already down to 75%. Maybe I should spend the morning discharging and recharging them all like AirData suggests.
Also me, 4 batteries later: Oh look, the last DJI firmware update seems to have reset the discharge time back to 2 days.
Oh this would be real useful so hopefully I can get full member soon .
You guys are so good with the info I’ve found in the searches I haven’t had much reason to ask questions. 
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Have just completed my overdue Basic service, prompted by reading a post on the daily updates which led me on to read other posts. Just one more example of the useful information I have gained from GADC. Thank you to all the members 2ho give their time and knowledge.
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When it comes to the maintenance of smart batteries it can be beneficial to perform a calibration of the battery management system. Quite often the assumption is made that a battery’s poor performance is due to its age and/or number of cycles. Throw a Battery Management System (BMS), used in Smart Batteries, then the true cause can become clouded. If a battery has been left idle at storage charge for a reasonable length of time the BMS may end up reporting the apparent health erroneously. It will record a voltage drop that accursed naturally over time, but as the battery will not have a load on it there will be no current draw recorded, and the true capacity will not be recorded.
Example.
I recently took delivery of a 3DR Solo supplied with four Smart Batteries, which were at storage charge levels. Once fully charged two of the batteries were being reported as having low capacity, one at 2750mAh and the other at 3680mAh. The true capacity of these batteries is 5100mAh. In use they showed a Voltage of approximately 15.5Volt with only 8% capacity remaining. Obviously the numbers do not add up for a 4S LiPo battery with a capacity of 5100mAh.
In the 3DR Solo third party APP for Android, Solex, there is a utility that allows the user to drain the battery down slowly to 3.0Volt per cell while constantly monitoring the internal temperature. It’s 3.0Volt per cell as I understand that 3V is the chemical charge value of a LiPo cell once assembled and before an external charge is applied. Once 3.0Volt per cell is reached the application shuts the drone off.
At this point the battery is left to stabilise for about 5hours before charging back up to 100%. Throughout this charging process the BMS monitors the amount of charge being supplied.
The battery is then left for approximately 48hrs on the charger, after 100% capacity is reached, so that the BMS can fine tune the balance of the four cells.
When I connected the batteries to the drone the reported capacity was back within the manufacturers specifications and the flight times were now what I would expect, rather than the less than 7minutes I was getting before the calibration process.
In the past I have performed this same process on my Phantom 2 batteries, which were forcing the drone to go into a forced landing after four minutes. After the calibration all batteries were providing at least 18minutes of flight time before the first level protection kicked in, and approximately 22minutes before the second level kicked in and forced a landing. I will point out that these batteries had not previously been used and they sat at storage charge for possibly two years or more.
Now the caveat.
This will not fix every low performing battery. Batteries will age at varying rates based on the amount of use, and the amount of abuse, whether they are Smart or not.
I flight tested a 3DR Iris Plus yesterday. This uses regular batteries i.e. no battery management circuit. The battery used was the supplied 3S 5500mAh pack which should provide at least 15minutes of flight time when carrying a gimbal and GoPro. In actuality I got about 2 minutes before the auto protection cut in and the drone was forcibly landed. In this situation there is nothing that can be done as the internal resistance of each cell was so high that the voltage drop caused by the load on take off was so great the flight controller wasn’t having any of it. In other words “The computer says no!”.
If you choose to do a calibration on a Smart battery do not start the process and walk away. Not every drone APP can monitor a battery’s discharge and auto switch off the battery at 3Volt. Possibly at best you kill the battery, at worst it’s internal temperature gets high enough for combustion of its internal goop.
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i have been practicing basic drone flight (I’m a total newbie) and I think i have wrecked me drone battery… landed when low battery warning came on.
when getting back to recharge i realised i failed to correctly shut down or switch off…battery is now refusing to charge.i suspect that it is below 3v.
Anybody have any suggestions?
What has probably happened is that the Battery Management System (BMS) has registered a power failure, and for safety reasons has prevented any charging via the smart charger.
There is a way to reactivate the battery if it is a DJI battery, but it does require access to the internal cells and reseting the BMS with a PC and a custom interface.
thanks for the reply…
sadly it is a go-pro karma and not a dji.
i have a spare battery and every thing works as it should. and the non-responding one gave a good half hour flying before me leaving it powered on…
i wont make that mistake again.
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