Hi everyone.
I was flying my P4P today. When I took off, I got a warning about the battery being too cold. That didn't make a lot of sense, cause outside the weather was very mild (Around 12 degrees Celcius). I've flown with much lower temperature conditions (2-3 degrees C) without ever getting any warning.

In any case, just to be safe, and as it would be practically impossible to raise the battery temp over 25 degC by just looking at it, I decided to just let it hover at around 3-4m height to 'warm it up'. Needless to say that I had to waste half of my battery time doing that (not cool). Then, I noticed that the red LED lights would stay on, without me getting any kind of warnings on my screen. The battery temp got higher than 25 degC, but the rear back LED lights would still be on. Strangely, whenever I was using my right stick (direction), the continious red light was replaced by blinking green (standard). Whenever I stopped using my right stick, it got back to continuous red.

It was kind of windy, but nothing too much, and eventually I flew two batteries without any problem, but with the red lights always on except when using the directions. I just was very nervous and didn't enjoy what would otherwise have been a nice photoshoot.


Any ideas? My Phantom has been showing several signs of weird behavior (apart from the above, I have some random jerking, and some weird 'hickups'), so I think after adding today's experience, I'm going to ask for a replacement, as I'm still within the return window. However, I'd like to understand what could be the problem.

Another issue, I'm mentioning it here so I don't start another thread, my focus is very problematic. 8 out of 10 times I tap to focus, the box starts from green and after less than a second becomes red. My footage doesn't look too bad, but still it's very annoying to not be confident about your shots. Any ideas?

You can be sure that any time you see red lamps in the rear, your AC is trying to warn you about - something.  

It's not the temp of the air you need to worry about.  It's more the temp of your battery and the temp of your AC.  You must always launch with a warm battery.  12 C is not even close to warm.  Re battery temp, you want at least 20 C but I would much rather have 25 C.  On a cold day, I won't fly with less than 25 C.  30 C is even better.  

Anyways - slow blinking red in the rear is low battery warning.  Fast blinking red in the rear is critical battery and auto-landing.  And this may be because the battery is cold.  Solid red could be anything.  You shouldn't fly with solid red.

Mark The Droner Posted at 2017-3-4 13:55
You can be sure that any time you see red lamps in the rear, your AC is trying to warn you about - something.  

It's not the temp of the air you need to worry about.  It's more the temp of your battery and the temp of your AC.  You must always launch with a warm battery.  12 C is not even close to warm.  Re battery temp, you want at least 20 C but I would much rather have 25 C.  On a cold day, I won't fly with less than 25 C.  30 C is even better.  

"12 C is not even close to warm."

It is not even close to cold, the battery can work fine below that temperature.

It's just weird, cause today it was the warmest day I flew since I got it, in previous times the temperature was around 5 deg. Celcius and never received this kind of warning again. Anywayz, I guess the red light didn't have to do with the battery temperature, as it stayed there after the temperature was over 25, while the second battery I used didn't even give me a low temp warning.

Is there any kind diagnostics procedure to see why I had this red light?

Geebax Posted at 2017-3-4 14:06
"12 C is not even close to warm."

It is not even close to cold, the battery can work fine below that temperature.

This is news to me.  My understanding was that the more modern DJI aircrafts won't even start up with a battery colder than 15 C.  Is this something new with the P4s?  What is the battery cold limit on P4s?  

Mark The Droner Posted at 2017-3-4 14:12
This is news to me.  My understanding was that the more modern DJI aircrafts won't even start up with a battery colder than 15 C.  Is this something new with the P4s?  What is the battery cold limit on P4s?

12C is 53 f, as far as batteries are concerned, that is not cold.

Geebax Posted at 2017-3-4 14:17
12C is 53 f, as far as batteries are concerned, that is not cold.

For the P4, right?  Because it's certainly too cold for all the other DJI aircrafts.  My understanding is the firmware won't allow the motors to start.  You're saying this has been changed for the P4.  I'm asking what is the new cold limit for the P4?  

http://www.phantompilots.com/threads/battery-cold-use.95080/

Shoot ahead to 7:20

Mark The Droner Posted at 2017-3-4 14:21
For the P4, right?  Because it's certainly too cold for all the other DJI aircrafts.  My understanding is the firmware won't allow the motors to start.  You're saying this has been changed for the P4.  I'm asking what is the new cold limit for the P4?

I would understand it if it blocked the motor from starting. But giving you a warning means that you have to handle it as a warning (fly carefully, stay low and close till it warms up). Also, I couldn't see how the temperature would just double itself just by looking at it. Warming up any kind of equipment means let it run conservatively till it reaches the right temperature. That's what I did.

What I like to do is warm my battery anytime I launch in cold air; that is, anytime I launch in air colder than 20C / 68 F.   I warm the battery to 25C - 30C.  Then I fly.  In fact, I just flew this morning in 27F weather, but I warmed the battery and the AC beforehand.  I don't just warm them to room temperature.  I warm them to 25C - 30C.  I do have an advantage of flying from my back property though.  

You can see the air temp and the battery temps overlayed in the video below:




Apparently, according to Geebax, there is some kind of new technology that allows you to fly a P4 with a 12 C battery,  I would check your P4 documentation on how cold it can go.  

I am not saying that there is any new kind of technology, I am saying 12C is not cold. I fly a P3P, and I deliberately shut off updates before this silly low battery warning thing was introduced. If a bettery gets down to 5C or below, yes, that is too cold.

I have to disagree.  12 C is way too cold for a lipo battery.  Sure, it might fly, but it's not worth the risk.  Warm the battery and remove the risk.  

When DJI doesn't allow you to fly due to a cold battery, it's not because they're trying to be mean.  They're trying to keep the battery from shutting itself off mid-flight.  


http://www.phantompilots.com/thr ... page-2#post-1120340

So, came back home and tried to explore the flight logs, to see if I can get any hint of why the red light was on.

Here, I have to say i've no idea what I'm looking at, but most of the things made some sense to me (pretty self-explanatory like altitude, battery temperature, voltage, acc, gyro, GPS, etc.)

The only thing that looked weird to me was that velocity_valid_flag_00, which was 'invalid' for the whole time. Any idea about what this might be? Another little weird thing: My starting altitude was.... -3m . I was next to a river, so I can say I was about 2m higher than water level. Is that offset normal?

PS. I was able to check the battery temperature I took off with: 14 deg. C., and it managed to rise to 25 in about 6-7 minutes.

Geebax Posted at 2017-3-4 14:06
"12 C is not even close to warm."

It is not even close to cold, the battery can work fine below that temperature.

It can work but it is recommended to be between 20 to 24C. Either way something was wrong with the battery and should NOT fly with a warning!

Mark The Droner Posted at 2017-3-4 13:55
You can be sure that any time you see red lamps in the rear, your AC is trying to warn you about - something.  

It's not the temp of the air you need to worry about.  It's more the temp of your battery and the temp of your AC.  You must always launch with a warm battery.  12 C is not even close to warm.  Re battery temp, you want at least 20 C but I would much rather have 25 C.  On a cold day, I won't fly with less than 25 C.  30 C is even better.  

Today for the first time, I experienced flashing red lights in ac rear, after a firmware update. Therefore, I appreciate your comments. Should you think of any other reasons for the red lights flashing, I would. Like to know, since I did not observe the rear lights' color upon liftoff. Thank you for your time and input. Falun

Falun Posted at 2018-6-2 09:31
Today for the first time, I experienced flashing red lights in ac rear, after a firmware update. Therefore, I appreciate your comments. Should you think of any other reasons for the red lights flashing, I would. Like to know, since I did not observe the rear lights' color upon liftoff. Thank you for your time and input. Falun

slow red flashing low battery...fast red flashing critical low battery..red lights flashing alternately IMU error.

Falun Posted at 2018-6-2 09:31
Today for the first time, I experienced flashing red lights in ac rear, after a firmware update. Therefore, I appreciate your comments. Should you think of any other reasons for the red lights flashing, I would. Like to know, since I did not observe the rear lights' color upon liftoff. Thank you for your time and input. Falun

Check your manual - there should be some notes on rear red lamp warnings.  Good luck.  

Mark The Droner Posted at 2017-3-4 13:55
You can be sure that any time you see red lamps in the rear, your AC is trying to warn you about - something.  

It's not the temp of the air you need to worry about.  It's more the temp of your battery and the temp of your AC.  You must always launch with a warm battery.  12 C is not even close to warm.  Re battery temp, you want at least 20 C but I would much rather have 25 C.  On a cold day, I won't fly with less than 25 C.  30 C is even better.  

Lol we would only have a few days a year to fly here in the UK if we had to wait for 25C - 30C+ lol! - But will warn you if the battery is below 15C

Aerial-Image Posted at 2018-6-4 10:08
Lol we would only have a few days a year to fly here in the UK if we had to wait for 25C - 30C+ lol!  - But will warn you if the battery is below 15C

I fly below 0C all the time.  I'm referring to the battery  

My P4P v2.0 flashes it's front LEDs red, but the rears on mine are green. Are they capable of changing color (bi color LEDs in there)? Just curious.