Anybody know when does the DJI Phantom 3 Standard balances the cells? I thought it did when it finished charging. So I put that one back on the charger and it was already 100% and the cycle count was 3 on for 12 hours (I turned it on before charging). Now they read 4.31, 4.30, 4.33, 4.26 and now the cycle count jumped to 4. But it didn't balance. Now I am trying when it does its self discharging thing. I'll know if that worked after Christmas. If this wasn't a damn intelligent battery, I could fix this in a couple of minutes.

I assumed it balanced on charging.  So i will be interested to learn how it actually does it.

Hi Bill ..... now I think you are getting to see why I am plugging so much about battery things here and other forums .... I hate DJI system of taking away from me manual control of battery states.

Nigel

solentlife Posted at 2016-12-23 10:46
Hi Bill ..... now I think you are getting to see why I am plugging so much about battery things here and other forums .... I hate DJI system of taking away from me manual control of battery states.

Nigel

There is nothing new about it, Sony and Canon have been doing it for years, and in the main it works. You might know how to deal with the battery, but the vast majority of people buying Phantoms don't have a clue, so the system is angled towards them.

I was always hopeful, that deep cycle of the battery voltage, might correct balancing differences. ;-$


RedHotPoker

RedHotPoker Posted at 2016-12-23 08:52
I was always hopeful, that deep cycle of the battery voltage, might correct balancing differences. ;-$

Absolutely not! You can't reverse a low internal resistance condition in a sealed battery cell. The individual cell voltage may seem to be balanced once individually charged but in reality the effected cell will always exhibit a higher self-discharge rate than the healthy cells.

With their infinite wisdom, DJI has provisioned their firmware to disable the drone if battery cell deviation exceeds a fixed limit. No magic chants or snake oil will undo this.

Betamace Posted at 2016-12-22 19:31
Absolutely not! You can't reverse a low internal resistance condition in a sealed battery cell. The individual cell voltage may seem to be balanced once individually charged but in reality the effected cell will always exhibit a higher self-discharge rate than the healthy cells.

With their infinite wisdom, DJI has provisioned their firmware to disable the drone if battery cell deviation exceeds a fixed limit. No magic chants or snake oil will undo this.

Yes, as I said, I had hoped. Reality overrules. Hahaha


RedHotPoker

RedHotPoker Posted at 2016-12-23 10:43
Yes, as I said, I had hoped. Reality overrules. Hahaha

Yep, keep on buying their batteries.... Or build your own packs.

Betamace Posted at 2016-12-22 19:54
Yep, keep on buying their batteries.

Oh I have, and hope to continue doing so. I bought the Plasticase Nanuk 945 just so that I could buy three more flight batteries and have seven total, in the case. ;-)

You have got to love RC hobby expenses. Never ending!! Or it's the wrong hobby. Hahaha


RedHotPoker

Reverse LOW internal resistance ? Strange .... its HIGH internal resistance that is the killer.

Second that deep discharge if not done cell by cell is deaths door to a lipo. The only good way to deep discharge a lipo is to do it cell by cell and only take down to 3.0v each cell.
If you try to do it by discharge of pack as a whole - then it is rated as a total voltage .... and any cell can be dragged below that 3.0v threshold and damaged. The pack may show 12v total - but individual cells can be different. For every cell above 3v means a cell below 3v.

12v lowest total voltage is based on the DJI battery being a 4S pack.

DJI in my opinion is giving bad advice to deep discharge a lipo. Without proper cell control - its asking for trouble.

Nigel

It seems from various reports now - that DJI balancing is 'suspect' ----- I am rec'g from various privately comments that battery inbalance does not get corrected ...
DJI technical has informed me that app tells me when battery is out if balance ! That's no good if I cannot manually balance the cells !

Nigel

Well if I understand DJI magic correctly, it won't let you drain the battery anymore when any one cell hits 3.0v. I guess this means to protect the battery, drop the bird. Sure you'll bust the landing skids, have to replace the camera, gimbal, shell, a couple of motors and blades... but hey the battery might be reusable.

It's supposed to balance during the charging process. Just to clarify, are you using the stock single battery charger or a different one?

solentlife Posted at 2016-12-23 14:48
Reverse LOW internal resistance ? Strange .... its HIGH internal resistance that is the killer.

Second that deep discharge if not done cell by cell is deaths door to a lipo. The only good way to deep discharge a lipo is to do it cell by cell and only take down to 3.0v each cell.

In the main I agree with you, particularly about discharging per cell so as to not go below the 3.0 volt limit, but how do you know that DJI do not do this already inside the battery?

At present I am using the stock charger - as to others who report lack of balancing I don't know.

But that is not important because the stock charger is a dumb power supply only. The balance function is not via the charger as most other models use - DJI have decided to have balance controlled via the battery internal board.

What is interesting is the reports I am getting saying that inbalance remains after charge ......

The standard answer from DJI is to deep discharge to enable battery to recalibrate - is nice for DJI .... Do that too often and new battery needed.

Hi Bill ..... I would like to see if it actually does stop when one cell hits 3.0v ....

DJI say that deep discharge also enables battery to recalibrate .... Interesting claim.

The more I hear / read about this so called intelligent battery - the more I dislike it. It may be good idea for newcomers to E-Flight who have no idea how to manage LiPo's - but majority of E-flight people do know what to do.

All we really need is access to the cells to do PROPER charge / balance routines .....

Nigel

DJI-Jamie Posted at 2016-12-23 17:44
It's supposed to balance during the charging process. Just to clarify, are you using the stock single battery charger or a different one?

It doesn't balance during the charging process (recharged four times now) and that hasn't balanced anything. Using the stock Phantom 3 Standard charger. I bet it balances during the self discharge cycle. Something I haven't tried yet.

To DJI team :

Please accept that in no way am I trying to undermine DJI, the model and general is a great design and unit.

My intention with this subject is to arrive at better understanding of the processes. Unfortunately so far - information given by DJI has been insufficient and conflicting. This certainly does not help owners or DJI.

DJI is held up as a world leader in AP multi-rotors. It is time for Technical Support to come up to the same quality level.

Nigel

BillW50 Posted at 2016-12-23 16:33
It doesn't balance during the charging process (recharged four times now) and that hasn't balanced anything. Using the stock Phantom 3 Standard charger. I bet it balances during the self discharge cycle. Something I haven't tried yet.

Did you ever get around to trying this? I'm very interested to hear if the battery balances during the self-discharge.

i have the same issue on a battery pack for P3 professional. It has only been discharged 14 times - was mostly just sitting on the shelf. First 3 cells are at 4.35V and last one is at 4.17 after charge. very dissapointed that this smart battery does not actually balance the cells...

My understanding is the smart battery does try to balance its cells, especially towards the very end of the charging process.  Old batteries, even with low cycle counts, aren't likely to behave as well as a new battery would.   Look at the mAh level of your battery at 100% charge and compare it to what it should be (i.e. 4480 mAh).  Your battery's 4th cell may have issues.  I would take a close look at the logs and see what your battery cells have been doing while aloft during the past few flights.  Look for extremes.  You might consider replacing the battery - or at the very least, try to land early in the flight like at around 50% depending on what you see when you review the logs.  Below is an example of a P3P flight with a battery with 3 cycles.  As you can see, the spread between cells never approaches where your battery spread starts before it's even off the ground (yours starts with a 180 mv spread before launch).  It seems to me there would be an excellent chance that 180 mv spread you have at start up could increase dramatically during flight.  My point is, a spread of 180 mv on start up may indicate a damaged cell.  Good luck.