Solution for P4 range/battery life issues - Updated with Contact from DJI!

[GadgetGuy]

Most Li-ions charge to 4.20V/cell(DJI 4.3V/Cell), and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles. So by charging it by 10% less you get over 100% more cycles and usable total time out of your battery, in exchange to 10% less usable time per charge...
Please do some research instead of speculating, http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Reread where I said your battery will outlive your P3 or P4 no matter how you charge or discharge it. Trying to increase cycles you will never use in the future, based upon "it is said" and written on the internet, by unnecessarily reducing your flight times seems like pure folly to me. Do as you like, and I'll do the same.

 

[GadgetGuy]

Give this man the trophy!

It's not worth worrying so much to save a few flights (MAYBE). Just do the general proper care and you won't cur your battery life in half or get an extra 50 flights out of it once the P6 is out and you already sold your P4 battery for $40 to a guy just "getting into the hobby"



What are you getting at? I am not trying to prove DJI right or wrong. Again, I have no horse in this race. To me 24 minutes flying time with a spec of 28 with time remaining is pretty on par with the specs, especially if you factor in the time I didn't fly that the battery had left, the windy, high altitude, and using all methods flying I was doing.

Go drive around your neighborhood in your i3 BMW and tell me if you get the EPA advertised MPG.

Now go on the highway with you Ford F1t50 and tell me if you the rated highway miles it advertises.

I am not getting into this conversation again. Any response to this by you, with no offense to you, will be ignored by me. I am not going to be in another one of these. I am really not sure why so many people here want to argue so bad. If this PhantomPilots was my house and we were in the bible, it would be the rusty corner and the memebers would be the contentious wife.

My only bone to pick with you was over your mistaken assumption that the last 10% of the remaining battery life is linear, and its flight duration could accurately be projected based upon the duration of the first 90% that was already consumed. If everyone were getting 24 minutes to 10% flying in any way we choose to, we'd all be happy. No one I have seen has posted any real P4 flight log of 28 minutes, after flying normally. I never expected 28 minutes. I did expect closer to 25 minutes than 12 minutes! Peace!

 

[Sky King]

Sorry to throw this thread into yet another tangent but since we are on the topic:

Does anyone know exactly what is the 0% battery behavior in flight? Assuming a worst case scenario over water, do you have a minute or so of reserve in auto land at 0%? I don't plan to ever subject my batteries to this test even if an inch off the ground is the reason for asking.


Sent from my iPhone using PhantomPilots mobile app

When you run out of "juice" it shuts off and plummets like a rock! How do I know that? I tested it on a P2 and thought that it would slowly lose power and land slowly. If you try to keep it in the air after it goes into "auto-land" or critical battery condition for any length of time, it will crash.

 

[GadgetGuy]

You mis understood.

I read the not below 60percent until 20 cycles when i got the bird home immediately after purchase long before I ever read that same reference on the internet yesterday.

I would not have followed that breakin guideline all this time otherwise.

With all due respect, your break-in procedure is just an unnecessary waste of time. However, It won't hurt anything, so, if it makes you feel better, do it. Just know that the vast majority of the rest of us follow no such break-in procedure, and all our batteries are outliving our aircraft.

 

[GadgetGuy]

When you run out of "juice" it shuts off and plummets like a rock! How do I know that? I tested it on a P2 and thought that it would slowly lose power and land slowly. If you try to keep it in the air after it goes into "auto-land" or critical battery condition for any length of time, it will crash.

It still depends upon the individual cell voltages, regardless of the percentage battery reading. As soon as any one of the four cells ever reaches 2.99V for even a second, say under an extreme load by flying full throttle upon a cool battery, the entire battery will shut off, whether in the air or on the ground. That's why properly balanced cell voltages are critical, because even if the app says 87% remaining battery, if any one cell is critically lower than the other three, your battery will shutoff, even if at 220 feet, 15 seconds into your flight! Ask me how I know!

 

[I M Dronaholic]

A little birdie told me the email of DJI's head "user experience" guy:
[email protected]

I have emailed him as well. Feel free to forward your experiences onward and upward to these gentlemen who gave us the specs!

Btw, the chief engineer for the Phantom 4 is Paul Pan:
[email protected]

I sent this...

I just wanted to let you know I am a huge fan of your products and have been an owner since day one of the P1. I also own several other all DJI drones for work and hobby. That said, I’m a little disappointed in the P’4’s range after replacing my crashed P3 with it. I do a lot of extended range work and when you introduced P4, it fit my needs exactly, on paper anyway, with avoidance and it’s claimed range and battery life….well, I’m kind of screwed with this setup, others may say the same. Just hoping you guys fix this, I need it lol.



Thanks for the tech,

-Marc Allan

 

[phantom1972]

Good post. Non engineers bitching about range, ignorant of inverse square law. Difference in output power prolly amounts to 50 yards.

Perhaps sensitivity, antenna design are the difference. Who knows. I don't know very many times I would want?need to fly out to 3 miles. How much battery would you have remaining once you got there/. Seriously.

I'm an Electrical Engineer. And I think you all are not interpreting the inverse square law correctly. For a given omnidirectional point source of EM Energy (Like Radio Waves), the waves (photons) go oiut in all directions, and the inverse square law can be easily visualized by the energy being evenly distributed as it moves through a surface area of a sphere a distance R from the source. For a sphere A = 4*pi*R^2. So the power at a point in space will decrease at a rate inversely proportionately to the range squared. BUT IF YOU START OUT WITH 20% LESS POWER, YOU'LL HAVE 20% LESS RECEIVED POWER AT ANY GIVEN RANGE. THE 20% REDUCED POWER FALLS OFF INVERSELY PROPORTIONAL TO R SQUARED TOO!

I haven't done a head to head comparison with my P3P's (Two) and my P4, but my initial impression is that the range of the P4 is significantly shorter in REAL WORLD conditions. Meaning, meaning if a tree gets in my way, I lose signal WAY faster than my P3P. For sheeple, who will faithfully control their drones only by sight, and not fly out of visual sight, then this can all be disregarded. If you want to make an epic video, and fly a couple miles out to sea, turn around and look at the shoreline in the late afternoon, and hear people gasp at the distance, then fly ashore, then fly a mile back to your takeoff point, skimming the surf, then you care about RC and HD Video Range. Fly behind a structure, go to FPV only (a piece of cake), loose signal, you care about RC and HD Range. Otherwise, a WiFi based system is fine.

 

[phantom1972]

Note that antennas are NOT omnidirectional sources of EM Radiation, they have gain (measured over a omnidirectional source, or a dipole). For identical antennas, I think if your starting power is down 20%, so is your received power at a given distance away from your source. So some easy range gain, is to only receive and send signals more directionally towards your bird. Specifically not backwards. That's the nature of the "gain" associated with Patch and Helical Antennas. IF THE P3P WAS FINE, WE SHOULDN'T HAVE TO JUMP THROUGH THESE HOOPS!

 

[2trickpony]

[QUOTE="So some easy range gain, is to only receive and send signals more directionally towards your bird. Specifically not backwards.[/QUOTE]
So does this mean that the antennas on the bird arent as important as the antennas on the transmitter for range?

 

[GadgetGuy]

"So some easy range gain, is to only receive and send signals more directionally towards your bird. Specifically not backwards.
So does this mean that the antennas on the bird arent as important as the antennas on the transmitter for range?

I believe he was suggesting that even a windsurfer on the stock P4 TX will vastly improve results, when it is pointed directly at the aircraft. It can almost triple the lousy range of the stock P4 Tx. Without a windsurfer, I get 2,500 feet. With one I get 6,700 feet. However, with an FPVLR v2 mod with boosters, I easily get 3+ miles with the P4, and with my boosted ITE-DBS02 setup, I have gotten up to 5.8 miles, which is at the very edge of the stock battery's flight time for a direct out and back flight, under ideal conditions, in the hands of an expert long range pilot, who can squeeze every last drop out of any setup! Eat your heart out Keith!

 

[wingtip85]

Dear Sir,
As a loyal DJI customer I wanted to bring to your attention an issue regarding the flight time of the new Phantom 4. Having owned the Phantom 3 and now the Phantom 4, I am quite concerned over the advertised flight time expectancy of 28 minutes. I realize that the 28 minutes would be under ideal situations but realistically we should see longer times than what we have been experiencing with our Phantom 3’s and that is not the case.
I am sure you or someone within your organization monitors the many forums and they must see all the negative comments being generated about this issue. Many are also dissatisfied with the range of the Phantom 4. It seems there has been about a 20-25% decrease in the power from the transmitter.
I am seriously considering returning my Phantom 4 within the 14 day grace period that Apple offers. It would be great if you could respond to this issue so I might make a more informed decision regarding my intention to return the Phantom 4.
I respectfully ask for some acknowledgment of this issue and a response.
Thank You,

I sent my email in ;-) I still may return my new P4 back to Best Buy and try the P3P instead...will save me some money anyway ;-)

 

[WWK888]

I sent my email in ;-) I still may return my new P4 back to Best Buy and try the P3P instead...will save me some money anyway ;-)

Even with some of the problems the P4 has I still love it and would not take it back. I am glad that I kept my P3P although I have only flown it once since I got my P4.

 

[Sim597]

I sent my email in ;-) I still may return my new P4 back to Best Buy and try the P3P instead...will save me some money anyway ;-)

Remember a lot of these guys are talking about the first P3P, I don't think the newer ones are 20% stronger signal, it is about the same for late model P3s. Unless I missed something but I have been following this and all threads related, I have a P3 RC with the modded itlite (GL300B) and haven't used the P4 remote yet, but going to tomorrow to see for myself. There's been claims the P4 remote is 3dB rssi better then the P3 GL300C remotes.


Sent from my iPhone using PhantomPilots mobile app

 

[Erised]

This is day 2 for me with my new P4. I'm not trying for distance yet. Today I flew for 7597 meters only 1600 meters out no signal loss. 50 meters up P mode all ON ,wind 5mph. Flight time 24 minutes and landed at 18% battery. Up time pretty good, I will try in atti.

 

[johnbowen]

20% less power really shouldn't effect range that much. Antenna sensitivity has a much more profound effect. Did you know you have to increase output power 4x to double range? It follows the inverse square law.

Inverse-square law - Wikipedia, the free encyclopedia

Re inverse square law. 20% decrease in power prolly equates to a 100 meter decrease in range. Could be something as antenna design within p4 shell.

 

[johnbowen]

GL300B (and GL300A) control output power at 0.38 watts is 25% more than the P4’s GL300C at .303 watts. Expect 25% more distance by changing. YMMV.

Wrong. Physics. I hate that it is so rational.

 

[johnbowen]

Good luck with that thought don't hold your breath, dji doesn't care about you or you complaints about their products. Js

I would concur with this statement. I paid over 1200 dollars for Lightbridge 1. DJI never fully developed an app for it. Within a year they gave up on further firmware or implementation of a proper app. To get it to work one has to keep their iOS devices on an earlier version. Then you have to find the year old beta version of their app, which requires installing a beta user profile on your device. DJI never received approval for their beta apps so it was not allowed to downloaded from the App Store. DJI quit spending time on updates to Lightbridge 1. It is about worthless. I can keep my iPad on an older version of iOS to use it, but otherwise I might as use it as a paperweight.

 

[johnbowen]

So you got more than the advertised range and if you would fly the battery to zero you would have had about 28 mins and you are returning it why? You guys are rediculous.

It's called sarcasm. I seriously doubt he returned it, unless his spouse griped about the 1400 dollar "toy".

 

[johnbowen]

I'm new to flying these and I read threads about cycling the batteries. I did it with my P3 batteries and I started with my P4. If you look at all my short flights in this pic, they all had approx 30-50% left when I was done. Then I saw all these people having range and battery problems so I wanted to try and see what mine would do. Look at the 24-25 min flights in the pic. They had 9 and 10% left. All these batteries have only been charged 2-3 times. I've seen some people say that you don't have to cycle the p4 batteries. What do you think? With the flight time I got out of these batteries with only a few cycles, do you think they are right that the P4 doesn't need to be cycled?


Sent from my iPhone using PhantomPilots mobile app

Chemistry, physics say no need to "break in' a LiPo battery, otherwise no one would purchase or lease a 150K Tesla (or 55k BMW i3 such as I own).

I would surmise what folks think is breaking in their batteries is more likely warmer temps now versus when they first received their P4 in cooler months.

 

[johnbowen]

Why is your statement "completely certain"? It is simply not true! What data do you have to support this statement? Check the individual battery cell voltages when the battery goes below 20%. They are still well above the voltages at which cell damage can occur! Even down to 5%, you'll still have cell voltages of around 3.5V/ cell. Would it change your opinion if I told you that DJI built an extra 20% cushion into the 0% readout in the app on the P4 batteries, such that a P4 at 0% is the same as a P3 at 20%, and a P4 at 20% is the same as a P3 at 40%?

My BMW i3 does same thing; battery capacity remaining visible to the user is actually reported lower than actual remaining battery capacity; all in an effort to sustain as long a life as possible for battery packs. It also uses active liquid cooling/heating throughout use and also during charging to maintain optimum battery temp.