But........this tcope reply above has said: Dji " No longer supports or wants US Drone owners to take their batteries to the 8% level " unless there's a "bad Imbalance"... in the cells !
The Pros and Cons of taking a Dji Battery to the 8% level to balance cells
- Thread starter MotorCycle-Man
- Start date
- Joined
- Dec 2, 2017
- Messages
- 49
- Reaction score
- 13
- Age
- 59
You are right my friend I have 5 and two of them new. Never yet used them other than keeping them at 30 percent level as a stage that I find to be adequate for the batteries health. I have had the 3 I used for 18 months and still at 85 percent at full charge. They do deplete as all batteries do. My first set of two only lasted 8 months using the DJI experts advice and according to the battery section of the manual in their maintenance and health of a longer life battery. I find it to be not the best way from my own experience. Try their way and experiment with the advice of the pilots here and we will win the argument and save yourself money and even save yourself from a fly away.
.OK......Say this : You do the best you can do on the care of a drones battery and never let it fall below 20% Or 30% as you do.......However IF you start to get "red flag" deviations in it On a few cells ..and the battery is nearing 20 re-charges .Ok what do You then prescribe a person to Do ! See thats my case here !with only "one" of my batteries ! I posted the volts a day after recharge But failed to add the Mah as requested ! that one battery had a 50 mv deviation.
Occasional 50mv deviations are probably of no concern. In any case the deep discharge routine probably wont help.
The few that have claimed the deep discharge routine served to correct cell balance issues found it was short lived. The best it might do is give the charge board a shot at getting the cells evenly topped off. The cause of the imbalance (internal cell resistance) cant be corrected through deep discharge. I’m not sure where @tcope is getting his information. It never worked for dumb lipo packs with any success, the cell tech is no different here as far as the LiION chemistry is concerned.
I can confirm the first two sentences above - re P2 batteries. Yes, it has brought the cells on some batteries closer to balance and within happy specs, and yes it was short lived. I've tried it with other out of balance P2 batteries and it didn't balance the cells at all. So it seems it works some of the time. Either way, the process robbed about 100 mAh from the battery.
In the P3P manual, the phrase "less than 8%" is used regarding discharging.
In the P3P manual, the phrase "less than 8%" is used regarding discharging.
Whoever wrote the discharge below 8% suggestion in the manual forgot to speak with the engineers at Texas Instruments (supplier of the battery management smarts) or they would have been informed how pointless that routine is in “re-calibrating” the batteries.
N017RW
Premium Pilot
Think there's more to it than just a blanket statement of certainty.
We'd need to see more TI specific info but the article below makes sense from a technical point of view when considering internal pack historical parameters are used for 'self evaluation'.
The article suggests that there is increased Fuel Gauge accuracy by an occasional deeper discharge. This may be more an issue for those who do not discharge to consistent levels such as random and sometimes frequent shallow discharges from short flights.
Since the art is continually improving DJI's reasons for discontinuing the suggested practice may be more financially (warranty, etc.) motivated than technical.
BU-603: How to Calibrate a “Smart” Battery – Battery University
We'd need to see more TI specific info but the article below makes sense from a technical point of view when considering internal pack historical parameters are used for 'self evaluation'.
The article suggests that there is increased Fuel Gauge accuracy by an occasional deeper discharge. This may be more an issue for those who do not discharge to consistent levels such as random and sometimes frequent shallow discharges from short flights.
Since the art is continually improving DJI's reasons for discontinuing the suggested practice may be more financially (warranty, etc.) motivated than technical.
BU-603: How to Calibrate a “Smart” Battery – Battery University
From the article “Some smart batteries feature impedance tracking. This is a self-learning algorithm that reduces or eliminates the need to calibrate. If calibration is required, however, several cycles instead of only one may be needed to achieve the same result as with a standard system.”...
Texas Instruments talk about this feature at length, they call it “impedence track”- it is part of the feature set included in the SOC employed in DJI smart batteries”. It is one of
many constantly updated parameters that inform the “fuel gauge” (remaining capacity” and “estimated time to empty” (remaining flight time).
N017RW
Premium Pilot
The information I posted is right from DJI (which is what I stated). The deep discharge is not to recondition the battery, it's to reset the circuitry that keeps track of the battery charge. This is within the battery itself.
Ok- well given the battery management solution implemented (which is well known and as you say inside the battery housing) the suggested deep discharge will not recalibrate anything.
I'm Sure that many many are viewing this post i started and i'm glad that we have the "knowledgeable Dji drone owners" out their that knows their stuff to Help me and many others too.....I'm sure watching these posts along with lots of others too "Thanks to all who added great money saving advice" ! With Over 400 views as of Right now !
I guess anything is possible but I'd tend to go with what the manufacture of the battery states (since they know all about the mechanics and software of their own batteries) and that they have reviewed this information enough to change the recommendation from every 20 charges to only when there is a certain issue.
It's not unreasonable that their software, working with the hardware of the battery, can still become "confused" as to the correct state of the battery and lose track of where the low charge of the battery occurs. This obvious was more of a problem in the past and perhaps their "fix" is not perfect.
If you look at the batteries it is evident there are at least two manufacturers that supply them to DJI as complete units. No doubt DJI would have been involved in the design of some components of the electronics however the battery management smarts are embedded in Texas Instruments IC’s, I’m going with their application notes and associated documentation as the authority here.
Do you still calibrate your compass before every flight? Up until recently DJI stated it was necessary.
Can’t give you a date- you will find it in the P3 manuals and many threads on this board and elsewhere.
Manual never stated this. It states whenever you changed flying locations. Never specified before every flight. Granted, whenever you change locations could be interpreted as many different things (1',.10', 1000', 1 mile, etc.).
I'm sure the hardware is made by several other companies. The hardware is 100% dumb and has no control. It's the software loaded into those chips. No indication that DJI was not in control of that.
Tcope I read the manual prior to my first flight (I extended my RC AC hobby to UAV’s with a P3) and sought clarification from DJI support re the instruction in the manual re compass calibration, specifically to calibrate “When flying in a new location or a location that is different to the most recent flight”. Clearly the strict interpretation of this is seemingly if you go from your back yard to the park down the road calibration is required. That didn’t seem logical so I faithfully listened to the DJI CSO advice which was, you might guess right, calibration is necessary in these circumstances. Of course it isn’t, my point is real world experience (yours and others) will often see you better informed than accepting things without question.
As to the battery software, the code that enables the battery monitoring functions and reporting is proprietary to Texas Instruments. Yes DJI (and other users) can modify the ROM flash with custom cell chemistry parameters and set limits for min capacity, LVC, etc however the algorithms that monitor health, total capacity etc can’t be modded by the end user.
Similar threads
