GadgetGuy's Final P4 Flight

[GadgetGuy]

I am correct in saying that new technology gets worse, when China make new batteries they lower the MAH below what they advertise, I've been ripped off that many times in other aircraft I should know.


Sent from my iPhone using PhantomPilots mobile app

Similarly, the "double wide" battery opening on the leaked P4 photos led everyone to think the battery would be twice the size of the P3 battery. In fact, it was just wide and very short, instead of wide and tall like the P2 and P3 batteries. The P4 battery even goes into the P4 case sideways, instead of on end. Combine the pre-release battery size deception with the P4 touted 28 minute flight time, and we all had very high hopes for the P4's battery life. Alas! 12 fits into 28 more than twice! 12 minute flight time, to 7% remaining, on the 3rd flight of a new battery (which needs no breaking in!) inside the latest and greatest P4 is just pathetic.

 

[chris digata]

very good info GG, here in the uk our tx is is limited by law but the p3p flys up to 3miles with no problems and the video is lost before RC.
with the p4 it flys to about 1 mile and RC is lost before Video.. thats great because i can see the rth kick in (joke)
Im having trouble keeping the shutter speed down on the camera and its dark alot of the time, no wonder they added a crap 3d noise filter (never used) as noise is bad.
Ive had no problems with battery times in the way I fly and the p4 has plenty left and takes longer to run down, but I never use below 30% as use a phantom for video and photography.
So yes I will be keeping the p4 but no way be loosing the P3P..
do you think they will discontinue the P3? or will all the flack they get make them do something...

 

[Noodle]

GadgetGuy, can you do one more test before you return your P4? Can you just fly at 50% throttle instead of maximum velocity, and see what is the battery time? Cheers.

 

[With The Birds]

Thanks for being a beta tester here GatgetGuy. It woukd be nice if DJI could inform us what "optimum conditions" are, specifically the test conditions whete they determine battery life. If we knew that we woukd have some idea what to expect in particular real world use.

Return on the basis that it doesn't perform as clsimed by the manufacturer and not fit for intended use (in addition to manufacturing defects.

 

[saltire]

I was so tempted to buy a new P4 but now i think its a used P3A or P3P with some extra battery's.

 

[rhoffart]

This is so weird ... It's like you own a totally different quad than my P4 ... My battery charges to 100% (on 4th charge now), my last flight yesterday landed at 18:00 minutes and had 38% left in the battery, camera is sharper then my P3P, and it holds GPS lock like it's fixed to the ground. I haven't done any long range testing but got out 2,000 feet and had full bars.

 

[Bbc14f]

This is so weird ... It's like you own a totally different quad than my P4 ... My battery charges to 100% (on 4th charge now), my last flight yesterday landed at 18:00 minutes and had 38% left in the battery, camera is sharper then my P3P, and it holds GPS lock like it's fixed to the ground. I haven't done any long range testing but got out 2,000 feet and had full bars.

Weird indeed

 

[phantom13flyer]

Similarly, the "double wide" battery opening on the leaked P4 photos led everyone to think the battery would be twice the size of the P3 battery. In fact, it was just wide and very short, instead of wide and tall like the P2 and P3 batteries. The P4 battery even goes into the P4 case sideways, instead of on end. Combine the pre-release battery size deception with the P4 touted 28 minute flight time, and we all had very high hopes for the P4's battery life. Alas! 12 fits into 28 more than twice! 12 minute flight time, to 7% remaining, on the 3rd flight of a new battery (which needs no breaking in!) inside the latest and greatest P4 is just pathetic.

Thank you for your solid review of the Phantom4. I tried the Gl300C controller that came with my p4 and wasn't impressed with the range so I ordered a GL300A unmodified and could only get 1 mile with it. So I'm debating which one to get modified for the DBS antenna. A couple guys have had great success with the "C" model. In fact yesterday I saw a 25,100 ft one way flight with the "C" model modified with the DBS antenna and 24 min flight time. This pilot Said there's room for the P4 to go 30k ft with the stock battery in good conditions . I'm not sure how these guys are flying in order to get that kind of flight times

 

[WetDog]

This is so weird ... It's like you own a totally different quad than my P4 ... My battery charges to 100% (on 4th charge now), my last flight yesterday landed at 18:00 minutes and had 38% left in the battery, camera is sharper then my P3P, and it holds GPS lock like it's fixed to the ground. I haven't done any long range testing but got out 2,000 feet and had full bars.

Not weird at all. Quality control - it's hard. We've seen literally dozens of P3 issues that affect some, but not all aircraft. Cases crack, vibrations, firmware upgrades fail. Video fails. Lenses misaligned. And much of the time DJI can fix the problem - sometimes to create another one.

This says to me that DJI has not mastered the art of making a complicated product work all of the time. Given the price point, I'm not terribly surprised (although Inspires seem to have this sort of issue). In the P3 era, DJI seemed to bend over backwards to fix the issues - printing out RMAs at the drop of a hat. Seems like the P4 is ushering a new set of rules that don't seem to be very friendly.

DJI seems to be an odd, complicated company. Part brilliant, part incredibly tone deaf and clumsy.

Interesting to watch.

 

[maseman88]

This is so weird ... It's like you own a totally different quad than my P4 ... My battery charges to 100% (on 4th charge now), my last flight yesterday landed at 18:00 minutes and had 38% left in the battery, camera is sharper then my P3P, and it holds GPS lock like it's fixed to the ground. I haven't done any long range testing but got out 2,000 feet and had full bars.

I have range issues but haven't gotten into a good area yet... Battery issues? None at all...

 

[Big Dog]

Where do you pull those flight records from? Am I using the wrong app?


Sent from my iPhone using PhantomPilots mobile app

 

[ringolong]

GadgetGuy's Final P4 Flight

I decided to give the P4 one final test to see if I could squeeze any more battery life out of it by flying only in Atti mode, which is the mode DJI used to arrive at their 28 minute flight time.

I have already given up on the P4 GL300C transmitter, and, instead, again paired the P4 with my FPVLR v2 modded GL300A with 3W boosters, just like on my second flight.

Once again, I could not top off the P4 battery above 95% before launch, as the new charger refuses to top off a slightly used battery, unlike the P3P charger. No matter whether I turned on the P4 battery before connecting it to the charger, or after connecting to the charger, in both cases, the battery immediately shut itself off, and stopped the charging process.

So, starting with the P4 battery charged as high as I could at 95% upon launch, with OAS turned off, front LED's turned off, channel 30 set on the hack, 4 Mbs set on the video transmission, I took off and immediately switched into Atti mode, flying in Orange instead of Green throughout the flight. During bootup, the gimbal made disturbing squealing sounds, but it has done that every other time, too, with no apparent side effects.

I flew as I always have, at full throttle, and speed was between 30 and 40 mph throughout. 2 to 3 second video dropouts started at the 3 mile mark, while flying at 40mph, which meant I had to stop until it recovered each time, but in Atti, it just drifts. No active braking, so no battery power consumed, like it would have been, in P-GPS or Sport mode.

However, battery was being consumed faster than I have ever seen before. I quickly turned around and headed for home. On the way back, the gimbal briefly locked up and stayed tilted at 45° for several seconds, while the app displayed a "gimbal angle exceeded" warning! Very disconcerting! I finally landed with only 7% remaining battery and had to fight hard to keep the aircraft aloft, during autoland after 10%, while maneuvering to a safe handcatch. I had flown 39,175 feet, but my total flight time was only 12 minutes, 19 seconds! She's a speed demon, but at a huge battery burn, and props are often in the frame, ruining the video. The "gimbal angle exceeded" error is a new one (which also ruins a continuous video), and should never happen in Atti mode, with no braking going on. Never seen anythin like that on my P3P.

1. My first P4 flight was 16 minutes, 14 seconds and 30,000 feet total with the stock TX in all modes.
2. My second flight P4 was 14 minutes, 40 seconds and 40,750 feet with my FPVLR in P-GPS mode.
3. My third and final P4 flight was 12 minute, 19 seconds and 39,175 with my FPVLR in Atti mode

Flight times are getting WORSE with each flight, not better, and even Atti mode cannot improve them!

DJI promised flight times exceeding 28 minutes, but is now actually delivering 12 minutes! Even TWO P4 batteries in parallel won't deliver 28 minute real world flying times on this aircraft. Also, the crappy video transmission from the aircraft cannot even be fixed with a transmitter mod.

Because I was so demoralized after this last P4 flight, I pulled out my W323 P3P, with its battery mod, and hooked it up to the same FPVLR setup just used with the P4.

I then flew my P3P directly over the same route as the P4, and just kept going, and going, and going! Flight time was 25 minutes, 37 seconds, over 66,000 feet, and I still had full video and control at 5.2 miles away, and returned with 15% remaining battery.

Final Conclusion: The P3P rocks! The P4 sucks! My DJI 7 day return period for manufacturing defects ends tomorrow. Shipping the P4 back to DJI in the morning! Already have my return shipping label! Plenty of manufacturing defects, between the defective battery, the defective control, and the squirrelly gimbal! I only need one. I found three!

See also: GadgetGuy's First Flight Impressions of the P4
and: GadgetGuy's Second P4 Flight Impressions

It sounds like a bad battery to me.

 

[maseman88]

Where do you pull those flight records from? Am I using the wrong app?


Sent from my iPhone using PhantomPilots mobile app

DJI Go? Here's the main screen...

 

[John Locke]

If you upload your flight log .txt file into msingers flight log reader I think you'll find some interesting data when you compare P4 to P3 numbers.

We all remember the P3P drama about the battery protection feature shutting down power mid-flight, right? That was firmware 1.5, the kiss of death firmware is what I call it. Then 1.6 fixed it by putting in a governor in the motherboard firmware that removed full throttle capability at 3.6V/cell (voltage display font color turns to orange). We all know about that, right? It seems the P3 batteries didn't have enough power during the last 1/3 of the charge to prevent voltages from dipping down significantly at full throttle, far enough to trigger battery protection. When batteries touched ~ 3.2V auto-landing would occur. If they touched ~ 3.0V, power would shut down with firmware 1.5 and the bird falls from the sky! This happened more so with cold batteries, because LiPo technology performs the worst when cold. To fix to this problem the 1.6 firmware prevented full throttle after reaching 3.6V, which I considered a band-aid to the problem. It's a throttle restriction to prevent huge voltage drops during the last minutes of the battery charge. It worked, and the problem was solved, at a small price of reduced performance during the last third of the battery charge. IMHO, battery protection should be forbidden to trigger while in flight, period. Screen warnings should display telling the pilot to land, and voltages displayed in big red numbers overlaying the video feed so you are clearly getting the message to return home and land. Informing the pilot of battery temperature would also be logical to include in the app, with BIG WARNINGS overlaying on the screen, BATTERY TEMP TOO LOW, and preventing take-off.

The battery protection flaw in P3 firmware 1.5 cost DJI a ton of cash in warranty replacements. Don't you think any new design would address this problem? I can just imagine the conversation Frank Wang had with the engineering manager about this.

OK, I remind you of the above because the P4 battery is bigger, however we are not seeing significant improvement in flight time as promised, only a marginal 2-3min additional (that's my experience) when landing at the same percent level (assuming you don't fly like a bat outta hell in S mode). Regardless of your flying style, when you compare P3 and P4 percentage levels versus voltage level/cell using msingers flight log reader, you'll see significant differences. It appears DJI has used the extra battery capacity of P4 battery to build in a bigger margin of safety to avoid battery protection scheme from triggering. Have you noticed that P4 DOES NOT reduce power at 3.6V? It will still do 13mph vertical ascents after 3.6V is reached, unlike P3 which slows down the craft.

When you compare numbers between P4 and P3, you'll notice that a 20% battery level is at a higher voltage level with P4 versus P3. 30% levels are at higher voltage too. I think that's a key design difference in the P4, DJI used a wider margin of safety at low battery levels, which reduces the flight time potential of the P4 battery. This of course could be tuned with new firmware, but I highly doubt DJI will do that.

Is this wider margin of safety a good thing? Some would say yes, anything to prevent birds falling form the sky. However this comes at a price of conservative flight times. It appears to me the margin of safety DJI has implemented in their battery percentage algorithm is overkill, based on what the industry recommends for LiPo battery discharge limits, while keeping batteries healthy as best possible.

Don't forget, the P4 motors are way more powerful than P3. The P4 has a top vertical speed of 13mph versus 11mph for P3, and the P4 weighs 100grams more! That means these motors have the potential to suck power like never before in a Phantom. I think that's another reason these higher capacity batteries aren't performing as expected.

I would be curious what you guys think of this hypothesis.

 

[Ramphex]

I get 12-13 minutes on average flying from 100% to 50%. Doing the 10 flight 100 to 50 battery calibration. Once that's done I'll do a full battery flight and will advise you of my findings.

All flights are either in GPS or Sport modes

 

[Big Dog]

Ooohh. Can't use that app on a p2v can you?


Sent from my iPhone using PhantomPilots mobile app

 

[sar104]

If you upload your flight log .txt file into msingers flight log reader I think you'll find some interesting data when you compare P4 to P3 numbers.

We all remember the P3P drama about the battery protection feature shutting down power mid-flight, right? That was firmware 1.5, the kiss of death firmware is what I call it. Then 1.6 fixed it by putting in a governor in the motherboard firmware that removed full throttle capability at 3.6V/cell (voltage display font color turns to orange). We all know about that, right? It seems the P3 batteries didn't have enough power during the last 1/3 of the charge to prevent voltages from dipping down significantly at full throttle, far enough to trigger battery protection. When batteries touched ~ 3.2V auto-landing would occur. If they touched ~ 3.0V, power would shut down with firmware 1.5 and the bird falls from the sky! This happened more so with cold batteries, because LiPo technology performs the worst when cold. To fix to this problem the 1.6 firmware prevented full throttle after reaching 3.6V, which I considered a band-aid to the problem. It's a throttle restriction to prevent huge voltage drops during the last minutes of the battery charge. It worked, and the problem was solved, at a small price of reduced performance during the last third of the battery charge. IMHO, battery protection should be forbidden to trigger while in flight, period. Screen warnings should display telling the pilot to land, and voltages displayed in big red numbers overlaying the video feed so you are clearly getting the message to return home and land. Informing the pilot of battery temperature would also be logical to include in the app, with BIG WARNINGS overlaying on the screen, BATTERY TEMP TOO LOW, and preventing take-off.

The battery protection flaw in P3 firmware 1.5 cost DJI a ton of cash in warranty replacements. Don't you think any new design would address this problem? I can just imagine the conversation Frank Wang had with the engineering manager about this.

OK, I remind you of the above because the P4 battery is bigger, however we are not seeing significant improvement in flight time as promised, only a marginal 2-3min additional (that's my experience) when landing at the same percent level (assuming you don't fly like a bat outta hell in S mode). Regardless of your flying style, when you compare P3 and P4 percentage levels versus voltage level/cell using msingers flight log reader, you'll see significant differences. It appears DJI has used the extra battery capacity of P4 battery to build in a bigger margin of safety to avoid battery protection scheme from triggering. Have you noticed that P4 DOES NOT reduce power at 3.6V? It will still do 13mph vertical ascents after 3.6V is reached, unlike P3 which slows down the craft.

When you compare numbers between P4 and P3, you'll notice that a 20% battery level is at a higher voltage level with P4 versus P3. 30% levels are at higher voltage too. I think that's a key design difference in the P4, DJI used a wider margin of safety at low battery levels, which reduces the flight time potential of the P4 battery. This of course could be tuned with new firmware, but I highly doubt DJI will do that.

Is this wider margin of safety a good thing? Some would say yes, anything to prevent birds falling form the sky. However this comes at a price of conservative flight times. It appears to me the margin of safety DJI has implemented in their battery percentage algorithm is overkill, based on what the industry recommends for LiPo battery discharge limits, while keeping batteries healthy as best possible.

Don't forget, the P4 motors are way more powerful than P3. The P4 has a top vertical speed of 13mph versus 11mph for P3, and the P4 weighs 100grams more! That means these motors have the potential to suck power like never before in a Phantom. I think that's another reason these higher capacity batteries aren't performing as expected.

I would be curious what you guys think of this hypothesis.

While I haven't had access to detailed voltage comparison data, that seems like a very credible hypothesis and a reasonable approach for DJI to take (if that is what they did). It might also explain why conservative flying gives significantly longer than expected flight times in comparison to aggressive flying.

 

[Ramphex]

Ooohh. Can't use that app on a p2v can you?


Sent from my iPhone using PhantomPilots mobile app

Support for P3 and up as well as Inspire and others. Doesn't say anything about p2

 

[Tron_X]

I've enjoyed my P3P since July 2015 and don't see any need to spend $1400 to get an inferior product. I pride myself on being an informed consumer, and not a brain-dead spender like so many Apple and DJI fan boys seem to relish being these days.

Stop stuffing $50's in G's at the strip club and you might be able to afford one. Plus, it's just not cool to pay for women.

 

[Bocephus-73]

Stop stuffing $50's in G's at the strip club and you might be able to afford one. Plus, it's just not cool to pay for women.

Looks like I hurt the delicate feelings of another DJI or Apple fan boi ---- that is the mark of a good day