Been running a new battery down because it wasn’t charging fully, it remained within .01 of every cell until I got down to 3.5v then some cells discharging faster
Have you had a chance to get a flight in with it
Yes but kept it within 150 - 200 yds as it drains quite quickly, only been charged 4 times, 5 now lol
I recently bought three 3rd party batteries for a Phantom2 that exhibited the same behaviour you describe. I discharged them all to around 3.4Volt/Cell, charged them back up to 100%, and now all three provide an average flight time of 25mins. It’s not the battery itself but the Battery Monitoring circuit inside the pack that is sending the wrong info to the Drone. Doing a deep discharge effectively recalibrates the circuit.
Thanks Nidge bud I’ll try that
@Nidge each cell down to about 3v ?
No! 3Volt/cell might be too low that the charger will not initiate a charge. Most hobby grade LiPo chargers if they see a voltage of 3.2Volt/cell or less will refuse to charge. The minimum I would go is around 3.5Volt/Cell, no lower than 3.4Volt/Cell in a no load situation.
Dave, those images show 3.8v which is good as that is the storage level, nothing to worry about
Also, the balance is good, within 0.01v of each other.
You have good packs there
Would be nice to see those screen shots after full charge so we can judge if they stay balanced
I’ll sort that out shortly @Steviegeek bud, in the process of recharging again so will take some more pics fully charged if the said battery fully charges this time lol
Bottom pic was 1st time after charging, took it out and rebooted and that’s top pic
Also knocked all batteries down to 3 days in the time to discharge, just something I read or watched somewhere lol
Moved all of this so that there’s just one thread about it and it had gone off-topic in the other thread.
Excellent point @Nidge
I work with EV batteries and the trouble we have with BMS’s is similar
Can’t understand the difficulties BMS functions are quite basic any good engineer given a decent budget should be able to come up with something that consistently works wether small or large packs
Off the soapbox now😆
Hi Dave @Matty1
Those look OK I have seen more perfect balancing on new packs but I’d be happy to use them for flight
I would keep a close eye on the individual cell voltage/balancing for the next few usages to build up your confidence
Been reading this Topic with interesting info & having looked at the Do’s & Dont’s of Safety usage of Mavic Air Battery I wondered how low you may have let your battery drop to and still been able to use a DJI ‘standard format‘ charger Individual or Multi to successfully recharge without issue The reason I ask is because of the statement in the DJI M-Air Battery info below
Let’s start with a bit of nostalgia.
Prior to the release of the Phantom 1 multirotors were solely the domain of experimental hobbyists. By their nature these hobbyists had an understanding of batteries and associated electronics as most were scratch built, using such materials as wooden frames and Arduino project boards.
DJI had for sometime been producing frame kits and purpose made electronics for the self builder but January 2013 they released the Phantom 1 ready to fly drone. Essentially this was a plastic monocoque body housing their existing range of electronics and was supplied with a generic 2200mAh 3cell 25C LiPo, terminated with the common XT60 connector and 4wire balance lead. This is where some of the problems started.
People with no prior experience of hobby flying and battery technology were buying the Phantom and treating it like any other consumer electrical item and getting unstuck very quickly. There were many tales of battery disasters as the users both drained the supplied battery to the point of death or overcharged it to the near point of causing death. Blade had similar issues when they released the 350QX, a Phantom competitor. This time the similar supplied battery was terminated with an EC-3 connector, as was and still is Horizon Hobbies preferred connector. The problem with this connector, even though keyed to only connect one way, would still allow the terminal pins to make contact when attempting to force a reversed connection. This resulted in the violent destruction of the Main Control Board.
With the introduction of the Phantom 2 range DJI implemented the use of the Smart Battery. This was just a regular low C rated LiPo but with a circuit that monitored the charge and discharge and the general health of the pack, taking out the guess work for those fully not up to speed. It was also a great excuse for DJI to ramp up the price. While the P2 was in production the price of the Smart Battery was around £120, where as the price of the LiPo used was only around £20 and the smart circuitry about another £10.
As I’ve previously shown in this thread the Smart (oxymoron) circuitry can get things wrong but it’s still very wise to follow DJI’s advice contained in the manual. DJI’s products are now established “Consumer” items and it is imperative for them to err on the side of caution.
Over discharging a LiPo battery increases the dendritic process (formation of lithium crystals on the anode) which will increase the cells internal resistance prohibiting it from charging and discharging correctly. The Smart tech is intended to prevent the user from doing this for obvious safety reasons. I was able to intentionally exceed these restrictions with my Phantom 2 batteries as I was able to monitor the terminal voltage, the individual cell voltages, the instantaneous current draw, and temperature of the pack during the discharge process and be instantly aware of any safety issues that were to arise.
99.99% of the time I would highly recommend that everyone follows the safety information contained in any electrical item manual, and if a battery appears to fail leave it at that and replace with a new one. Only investigate further if you feel you have the experience and knowledge to SAFELY investigate further.
Thank you Nidge for your last post I really do look forward to seeing your comments come up when they do your technical insights are of great value to me
The thing that got me thinking and subsequently asking was the statement you made above which reminded me of the ‘flick the terminals with touching wires” tricks us electricians use to use to jump start our Battery drills NiCad powered battery when it decided it no longer wanted to take a charge
I guess what I was trying to understand was why 3v
I guess retrospectively I should just have asked you that Q
As they say on the TV Don’t try this at home
Morning Nidge, can I bother you with a question about batteries???
In case you say yes(!) I’ll continue… Yesterday flying my Inspire 2 in windy conditions I switched to atti mode for practice. Aside from the questionable idea to do this with the batteries at 30% I had the notification, “Propulsion output has been limited to ensure battery health” deviation 0.004v. I then had, “Not Enough Force/ESC Error” while battling to get the drone back (flying into the wind) - deviation 0.007v
While flying I have noticed on the display when looking at the battery cells, some occasionally turn from green to yellow and the Airdata tells me that DJI’s smart batteries tell it that the batteries are still, after 76 and 80 cycles, still at 100% battery life.
From what I have said, I would be really grateful for your opinion about the batteries and whether I should perhaps replace them. Many thanks in advance!!!