P3A fell out of sky... can someone look at data and explain???

[Vertigo]

There are only 2 CSC positions for the P3

They list 4 here:
Combination Stick Command - DJI Wiki

Regardless if its 2 or 4, its still a stupid concept.

 

[msinger]

They list 4 here:
Combination Stick Command - DJI Wiki

True. Only these two will work though:

 

[MikeyOnline]

The biggest tip I ever received regarding orientation was in a video. You don't actually have to be able to see the front of the AC. You just have to be able to see the AC.

That's exactly what I do and have done for years. To clarify, when he says "turn", he means "yaw". For example (assuming default mode 2), you see a dot in the distance and you go up on the right stick to give forward movement (I usually go between 1/4 and 1/2 right stick up). If the dot moves to the left, slowly yaw left by moving the left stick to the left while continuing to hold the right stick forward for forward movement. Release the left stick to center when the dot looks like it is no longer moving left or right and you're still holding the right stick up... and it'll be coming toward you. Just reverse the "left" to a "right" on the left stick if it is moving to the right.

Now, here's the important part. If when you give it some forward movement with right stick up, you don't see any movement left or right, it could be going straight away from you or straight toward you. To get your orientation, if the dot doesn't move after about a second of up on the right stick, you must give it some yaw on the left stick (left or right, doesn't matter) until it does move left or right to get your orientation. Once it does start moving left or right, continue with the above paragraph. I don't think the case was mentioned in the video where you go up on the right stick and it doesn't move... or moves very little. In such a case, you must yaw in either direction until it does move left or right before you can use the procedure.

Mike

 

[royster]

That is a great tip,
Thank you for posting!

 

[BayouBill]

You should not take off unless battery is fully charged. Sometimes it causes battery % in app to be inaccurate.


Sent from my iPhone using PhantomPilots mobile app

Yes, inaccurate percentage display is definitely a flaw. Best policy is to monitor the cell voltages. Any cell below 3.5 Volts means time to land ASAP.

 

[Vertigo]

That's exactly what I do and have done for years. To clarify, when he says "turn", he means "yaw". For example (assuming default mode 2), you see a dot in the distance and you go up on the right stick to give forward movement (I usually go between 1/4 and 1/2 right stick up). If the dot moves to the left, slowly yaw left by moving the left stick to the left while continuing to hold the right stick forward for forward movement. Release the left stick to center when the dot looks like it is no longer moving left or right and you're still holding the right stick up... and it'll be coming toward you. Just reverse the "left" to a "right" on the left stick if it is moving to the right.

Now, here's the important part. If when you give it some forward movement with right stick up, you don't see any movement left or right, it could be going straight away from you or straight toward you. To get your orientation, if the dot doesn't move after about a second of up on the right stick, you must give it some yaw on the left stick (left or right, doesn't matter) until it does move left or right to get your orientation. Once it does start moving left or right, continue with the above paragraph. I don't think the case was mentioned in the video where you go up on the right stick and it doesn't move... or moves very little. In such a case, you must yaw in either direction until it does move left or right before you can use the procedure.

Mike

I have no idea why you'd yaw in your example, as yaw rotation is the hardest thing to judge at a distance, and its the only control where the stick does not command an absolute attitude, but a relative change, and thus, if you cant see your quads orientation, you're not going to know if you yawed 45, 90 or 180 degree.

So if pitch control doesnt show a lateral movement, because the quad's nose or tail is pointing to you, then just use roll control and see if it moves left or right.

 

[Fifty7]

I have no idea why you'd yaw in your example, as yaw rotation is the hardest thing to judge at a distance, and its the only control where the stick does not command an absolute attitude, but a relative change, and thus, if you cant see your quads orientation, you're not going to know if you yawed 45, 90 or 180 degree.

So if pitch control doesnt show a lateral movement, because the quad's nose or tail is pointing to you, then just use roll control and see if it moves left or right.

I think he was saying that you still wouldn't know if it was facing towards or away from at a distance you so you would need to turn it a little to determine direction

 

[Mark The Droner]

Yes. Without IOC available, you'd need to know where it's pointing so you can drive it home. It's an old school quadcopter flying technique and it still works today.

 

[BayouBill]

According to the DatCon KML and CSV (and your TXT flight log), you did a CSC on top of your neighbor's house. Your sticks were in this position at that time:

View attachment 60128

View attachment 60127

Thanks for this diagnosis. I'm sure everyone has learned from this thread.
But since we are on the subject of flying with fully charged batteries.....
Topping up before every flight could reduce the life of your batteries. I have been researching electric cars in hopes of purchasing one. Of course the greatest topic of discussion on the forums is battery life because they are VERY expensive. When manufacturers researched prematurely failing batteries one prominent cause was topping up the batteries routinely every night regardless of the level of charge. And another most frequent cause was heat. The chemistry in most of the current crop of EVs is the same as our Phantom batteries. And the EV chargers are far more sophisticated than the hobby chargers we use. I was not aware that topping up was a problem for lithium batteries but that could explain why I have so many swollen battery packs (not Phantom). I always top up before flying any of my RC birds.

I'm sorry for introducing more confusion on the battery issue but this only reinforces the idea that it is OK to fly with less than full charge if you carefully check the individual cell voltages under load (hovering) and temperature before taking off on a mission.

 

[FantomFlier]

... this only reinforces the idea that it is OK to fly with less than full charge if you carefully check the individual cell voltages under load (hovering) and temperature before taking off on a mission.

Agreed 100%. Can I add that it is wise to take off gently under these conditions. Do NOT launch up and out at full throttle!

 

[Vertigo]

When manufacturers researched prematurely failing batteries one prominent cause was topping up the batteries routinely every night regardless of the level of charge.

Do you have some links or more data? The above could also relate to something we all know, that storing lipo's fully charged is not good for them. If you top up your EV every day and dont drive every day, or typically only short distances, then you are essentially storing the batteries almost fully charged over the long term. That is bad for them, but Im not yet convinced the topping up itself is a major factor, but willing to change my mind when given more data.

Also, are you sure we are using the same chemistry? There are so many different types of lithium polymer batteries: Types of Lithium-ion Batteries – Battery University

I recognize LifePo4 (which I tend to use for my transmitters), the rest I have no idea.

And another most frequent cause was heat.

Again, this could be related to long term storage. Ive seen tests of a fully charged lipo battery stored long term at various temperatures and the difference was enormous. At 0C there was almost no impact and at 40C, the capacity loss over the course of a year was on the order of 50% or something (dont remember exact numbers, but that was the ballpark).

That doesnt mean that high temperature is really a problem in the short term, for the 15 minutes or so we use these batteries. In fact, temperatures up to ~40C increase the batteries performance.

I was not aware that topping up was a problem for lithium batteries but that could explain why I have so many swollen battery packs (not Phantom). I always top up before flying any of my RC birds.

Hardly scientific, but in my experience, over discharge is the number 1 reason of swelling, along with insufficient C rating (which results in under voltage under load). I also always top up my batteries, and on top of that, have a bad habit of charging them and then not going to fly, and thus storing them charged. I wouldnt say my batteries last forever, but I have very few puffed lipo's.

I'm sorry for introducing more confusion on the battery issue but this only reinforces the idea that it is OK to fly with less than full charge if you carefully check the individual cell voltages under load (hovering) and temperature before taking off on a mission.

This, I agree with completely. Voltage is always my primary gauge. Even on my FPV planes that have an amp sensor and the OSD tells me how many mAH I consumed, I still go by voltage.

 

[BayouBill]

Do you have some links or more data? The above could also relate to something we all know, that storing lipo's fully charged is not good for them. If you top up your EV every day and dont drive every day, or typically only short distances, then you are essentially storing the batteries almost fully charged over the long term. That is bad for them, but Im not yet convinced the topping up itself is a major factor, but willing to change my mind when given more data.

I will try to dig up some of the research I did - been awhile. I agree that fully charged storage could be related to the top-up issue. I also frequently charge fully and then don't fly for several days. Also my charger does not automatically do storage charge and I usually forget to stop it.
EDIT: Just found this article where Nissan RECOMMENDS topping up lithium ion batteries: Nissan Discusses Method For Topping Off LEAF Battery
Also found several articles that recommend charging to only 80%. Seems like battery management is something like voodoo.

 

[N017RW]

There's no VooDoo just lots of crap on the web to wade through.

Storage level is 50%. That's the level they are at when purchased.

Topping-off is not an issue for LiPos.

 

[Klnyc]

Not meant hijack the OP. just last weekend I flew my Adv. like 4 mins of flight the Dji app showing the battery NA, but I still can control the bird. it was a scary moment and I think I know why. I think I didn't push the battery all the way in, it didn't make that click sound.

 

[Yiannis.B]

Do you have some links or more data? The above could also relate to something we all know, that storing lipo's fully charged is not good for them. If you top up your EV every day and dont drive every day, or typically only short distances, then you are essentially storing the batteries almost fully charged over the long term. That is bad for them, but Im not yet convinced the topping up itself is a major factor, but willing to change my mind when given more data.
.......

BTW, great article.

Understanding RC LiPo Batteries

"Maximum Charge Voltage and Current

A 3.7 volt RC LiPo battery cell is 100% charged when it reaches 4.2 volts. Charging it past that will
shorten life substantially. In fact, the cell phone industry did a study looking at the effect of LiPo
fully charged voltages in relation to cycle life. These tests were done under ideal laboratory
conditions and of course the 80% depth of discharge rule was obeyed! Here are the results:

Charge to 4.1V gave over 2000 cycles.
Charge to 4.2V gave about 500 cycles.
Charge to 4.3V gave under 100 cycles.
Charge to 4.4V gave less than 5 cycles.

Folks in the RC world have reported similar results and one ongoing test seems to
indicate if you set your maximum charge voltage to 4.15 volts per cell (if your
computerized charge gives you that option), you should be able to get about 800
cycles (again if all the other LiPo usage rules are religiously obeyed). More and more
people are considering this 4.15 termination voltage the "sweet spot" for both
performance and cycle life for RC usage. Most RC chargers don't give you that ability,
but if yours does, you may want to consider it."

 

[Mark The Droner]

I just wanted to point out that apparently the P3 Lipo is newer technology right? So it's actually 3.8 volt per cell nominal charge (15.2 volt battery). So I suppose one would add a tenth of a volt to the above numbers... ?

 

[flyNfrank]

I'm sorry for introducing more confusion on the battery issue but this only reinforces the idea that it is OK to fly with less than full charge if you carefully check the individual cell voltages under load (hovering) and temperature before taking off on a mission.

This unfortunately is not going to show you what needs to be seen. What the aircraft does while hovering almost means nothing in terms of actual flying. You mention individual cell's being under a load while hovering, and the problem is there is no real load taking place at that stage.

It's the actual flying that generates a load. The more stick input, the more load. Weak cell's, headwinds, air temps plus more are going to be where you'll want to focus most of your attention.

 

[BayouBill]

This unfortunately is not going to show you what needs to be seen. What the aircraft does while hovering almost means nothing in terms of actual flying. You mention individual cell's being under a load while hovering, and the problem is there is no real load taking place at that stage.

Hovering generates a whole heck of a lot more load than sitting on the ground with the motors idle! Try hovering in place and see how long you can stay up.

 

[flyNfrank]

Hovering generates a whole heck of a lot more load than sitting on the ground with the motors idle! Try hovering in place and see how long you can stay up.

I don't need to try it. I've been around long enough to know that hovering loads are nothing when compared to in flight loads. I also read numerous amounts of flight data daily. I have the ability to see how much load each of the 4 motors is under at any part of the flight. And it's because of that is why I responded to the hovering statement.

 

[Yiannis.B]

I just wanted to point out that apparently the P3 Lipo is newer technology right? So it's actually 3.8 volt per cell nominal charge (15.2 volt battery). So I suppose one would add a tenth of a volt to the above numbers... ?

Well, I never noticed that before.

It seems that P3 Lipo battery is of newer technology.

It has more than 4,3V when fully charged.

They call them HVLiPo, and they are becoming more popular in RC models that demand high discharge rates (check 80C-160C)

Chemistry may vary :

Lithium Nickel Manganese Cobalt Oxide: LiNiMnCoO2. cathode, graphite anode
Short form: NMC (NCM, CMN, CNM, MNC, MCN similar with different metal combinations) Since 2008

Types of Lithium-ion Batteries – Battery University