Thanks Yes I see you have a vast knowledge of these batteries.When I purchased my drone I was lied to by the company who sold it to me.Droneworld Cape Town.They said all the updates had been done. The App.gave me no indication that there was a firmware update available.Just by chance I went onto the DJI website and found the very last firmware update for the P3 series.I did the update on the bird and the remote controller.And from there on every OEM battery I have fitted has never asked for a update?Except this one.I also have noticed that there is a 0.02v difference in the 1st.cell compared to the next 3 cells.OK, keeping it simple. 1 "C" for any given battery (a battery being a group of cells) is equal to the current rating of that battery. So for a 5200mAh battery 1C = 5.2a. Not taking into account losses through heat etc of which of course in the real world there are some if you discharge a battery to flat in 20 minutes it will be discharging at 3C or 3 times the rated capacity per hour.
For "dumb" batteries without an onboard controller like those used in R/C models (some) are capable of discharging safely at up to 10C (they get very hot), so you could flatten a fully charged battery in 6 minutes. This is the main draw of Lithium based batteries particularly Lithium Ion and Lithium Polymer, the chemistry that makes this possible is also what makes them so volatile if treated incorrectly.
I'm not sure what the maximum rated safe discharge for DJI batteries is but they are not "dumb" batteries and the onboard controller circuit will (should) manage that for you. As far as charging goes, while once again they *can* be charged at greater than 1C, for maximum battery life you should limit charge to 1C. So that 5200mAh battery should be charged at no more than 5.2 amps. In a perfect world this would mean one hour to charge the battery, taking into account losses through heat and other variables it's usually about 70 to 90 minutes. Once again the onboard controller on the DJI batteries manages that for you. The charger I use for my dumb batteries cost me $600 but it charges on 4 channels simultaneously and manages cell balancing and all the other factors once pre programmed. DJI batteries are a blessing for those who don't want to go that far into it as they just use a "dumb" charger and let the batteries circuitry mange it all for you.
Yes you have that correct. The Genuine DJI P4 dock I have makes it very clear it is only charging one at a time when set to "Charge" although it manages all three batteries at once when set to "storage" as some may be discharging while others charge. You're not the only person I have heard report dis satisfaction with 3rd party charger docks. It's also why I have a preference for OEM batteries over after market, I know that it has the genuine charger circuitry onboard not just a cheap knock of that does nothing but make the LEDs flash. I have been told that there are some good after market batteries but as I am a commercial operator I am obliged to use OEM to keep my liability insurance sweet.
For people with older DJI birds, because let's face it there is going to come a day when genuine batteries are not available, I would be thinking of putting your old and tired batteries into cold storage for the future and having them repacked professionally by a local battery specialist as that way you will be keeping your genuine DJI controller circuitry.
The Spark Dock seems to do all three at once also but they are a much smaller rated battery so the charger pack can probably manage it.
Yes this is correct although the way it is worded can be confusing.
Because it is a smart battery it is constantly doing things behind the scenes and communicating with the R.P.A. in flight to check on discharge rates, report on remaining capacity so your DJI app can report it to you and many other variables.
When they update the firmware on your RPA or it's controller this may effect the required communications between the bird and the battery or the manufacturer may decide to change the maximum allowed discharge rate for some reason, for example when the P4P V2 got sinusoidal ESCs and motors over the old square wave of the version 1. So for this case they have made the smart controller circuitry in the battery able to be updated also.
What is claimed to be the case and indeed what has happened for me (although I don't own a P3) is that when a new firmware update becomes available the App informs me and I go through the update procedure which flashes the RPA, the controller and the battery in one go if needed (sometimes the battery does not get an update as the existing parameters are fine). If the battery IS updated that updated battery firmware is stored on the R.P.A. so all you need to do it shut down the RPA, swap batteres and turn it back on and you will get a message to the effect that you have mis matching firmware versions and you follow the prompts and it will flash the battery for you in a short period of time.
I hope that is of some help and was clear enough to follow.