Motor cooldown Between flights
3408 21 2017-9-12
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MorganLeFay
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Sorry, Everyone, I'm new DJI. I have a P4P. I've been flying Rc Helis then Multirotors for years as a hobbyist. Mostly toy types. I have always read you need to wait 10 minutes or so between flights to let the motor(s) cooldown. I also read that you need to let the battery cooldown before charging. So here is my question. Do I need to wait between flights to let my New P4P cooldown? Does a cooldown between flights extend the life of the brushless motors? Thank you for reading.

Sincerely,
M
2017-9-12
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DJI Susan
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I would recommend to cool down the drone after several flights. Due to that the battery working temperature is -10℃ to 40℃, using the battery in environments above 50℃ can lead to a fire or explosion.
2017-9-12
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MorganLeFay
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DJI Susan Posted at 2017-9-12 23:03
I would recommend to cool down the drone after several flights. Due to that the battery working temperature is -10℃ to 40℃, using the battery in environments above 50℃ can lead to a fire or explosion.

Thank you very much!
2017-9-12
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BagoDJIoperator
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I always let my batteries cool down before charging so it doesnt over heat, I check always check the batteries temp when flying so I have an idea what they are operating at.
2017-9-13
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MrRobert5823
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I am not sure I understood the question... Was the cool down for the battery or for the motors?  If you are swapping batteries, from a warm yet near depleted battery for a new fresh cool one, then I would say there is little need for a cool down period for the motors.... Open to other opinions, but that's what I would expect.  Your batteries should NOT be flown multiple times, due to heat issues, but I would think if you swap them out, you should be fine.  
2017-9-13
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RedHotPoker
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I have four flight packs, so can fly pretty much consecutive flights.
With no way to charge batteries when at the park, they are plenty cool by the time I return home.

If you need to charge a battery that is still slightly warm, just turn it on before you attach the charger.

I have an infrared heat thermometer but have never bothered checking my drone motors with it, after a flight.


RedHotPoker
2017-9-13
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george_007
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The batteries have built in protection that prevents you from charging them if they are too hot.
So you can't really fail on that even if you tried. The battery will blink with one light and charging
will not start. It's described more in detail in the manual.

As far as the motors go most rc car drivers seems to want to keep their motors below 170F, 75C.
That's very hot to the touch. I believe our motors are running a lot cooler since they are cooled by
the passing air when we fly. Don't think you need a cool down for the motors.
2017-9-13
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Mike-the-cat
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george_007 Posted at 2017-9-13 13:00
The batteries have built in protection that prevents you from charging them if they are too hot.
So you can't really fail on that even if you tried. The battery will blink with one light and charging
will not start. It's described more in detail in the manual.

excellent post and I concur with your points
2017-9-13
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RedHotPoker
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george_007 Posted at 2017-9-13 13:00
The batteries have built in protection that prevents you from charging them if they are too hot.
So you can't really fail on that even if you tried. The battery will blink with one light and charging
will not start. It's described more in detail in the manual.

But you can trigger charging a warm battery, by turning it on, before starting the charging process.


Why would that ability exist, if it was harmful to the intelligent flight pack?


RedHotPoker
2017-9-13
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Phantom-Paul 7
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I have checked my motors using the same infrared thermometer we use on the cars and they have never gone over 35 degrees C    [ 95 f ] .  
I would be more concerned about the temperature of the electronics trapped inside , such as the flight controller or gimbal after several consecutive flights.
2017-9-13
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Genghis9
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RedHotPoker Posted at 2017-9-13 13:35
But you can trigger charging a warm battery, by turning it on, before starting the charging process.

Because you can defeat a restriction does not mean you should.  My understanding is George_007 is correct, the batt will not allow charging until its temp is within limits on or off.  Now that may not be the actual case, as you point out, but as I noted it sure doesn't make it OK.
The only time the manual states anything about turning a batt on is when it is at 95% or above charged and you are looking to top it off.
P4P manual v1.2 page 33 item 2
Ref page 31 manual v1.2 item 5 "battery will only charge when the temperature is between 5 C (41 F) and 40 C (104 F)"  Temperature is that of the battery not ambient
2017-9-13
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Genghis9
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In general and as a rule I will not charger my Batts until they are cool to the touch, which to date has taken about 10 to 20 minutes.  However, as the manual indicates high outside temps will obviously cause the Batts to be hotter, and it is prudent to take that in to account when charging.  You can mitigate it by doing so inside an AC area or using cooling fans etc.
Additionally, it ends up being about 10 minutes or so between my flights so the motors do get a short cooling period, but as noted previous they are air cooled by the props too.  I have not yet checked my motors after flight, maybe I should, but I would think a simple touch test to see if any is hot to the touch or hotter than the others (that would possibly indicate a problem).
All in all in this area, if is subjective as to how you should decide your own parameters and conducting your own flight ops.
Good luck and enjoy
2017-9-13
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MorganLeFay
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MrRobert5823 Posted at 2017-9-13 09:51
I am not sure I understood the question... Was the cool down for the battery or for the motors?  If you are swapping batteries, from a warm yet near depleted battery for a new fresh cool one, then I would say there is little need for a cool down period for the motors.... Open to other opinions, but that's what I would expect.  Your batteries should NOT be flown multiple times, due to heat issues, but I would think if you swap them out, you should be fine.

TY I was asking about the Motors.
2017-9-13
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TN Lone Wolf
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Never thought about letting the motors cool down.  But then again, I've never really noticed them getting that hot, especially compared to the heat produced by the battery.
2017-9-13
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Tmygun
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MorganLeFay Posted at 2017-9-13 17:05
TY I was asking about the Motors.

I check my motors after every flight with the non-scientific touch method......if they seem ALMOST too hot to touch....I wait....... take my aircraft to a shady spot and wait a few minutes.  
Rarely happens and only  when its really hot and sunny outside.
Reality is its a judgment call....there are no hard and fast rules that I have ever been able to find about the motors.
Just like there is no universal way to measure internal battery temps after use to determine when to optimally charge them again.   
Use common sense.  If there were hard specs about the motors....we would know about them.

Good Luck!
2017-9-13
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MorganLeFay
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Tmygun Posted at 2017-9-13 17:50
I check my motors after every flight with the non-scientific touch method......if they seem ALMOST too hot to touch....I wait....... take my aircraft to a shady spot and wait a few minutes.  
Rarely happens and only  when its really hot and sunny outside.
Reality is its a judgment call....there are no hard and fast rules that I have ever been able to find about the motors.

I have an IR thermometer, I'll be testing the motor temps and posting them. TYVM!!!
2017-9-22
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Labroides
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MorganLeFay Posted at 2017-9-22 21:53
I have an IR thermometer, I'll be testing the motor temps and posting them. TYVM!!!

DJI have run drones for 72 hrs continuously.
There's no need for any cool-down between flights.
2017-9-22
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Tmygun
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MorganLeFay Posted at 2017-9-22 21:53
I have an IR thermometer, I'll be testing the motor temps and posting them. TYVM!!!

Looking forward to the temps.  Also post the environmental factors  when you take the readings,
2017-9-23
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Blue Ridge Big
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Labroides Posted at 2017-9-22 22:26
DJI have run drones for 72 hrs continuously.
There's no need for any cool-down between flights.

I have found that my aircraft flies better if I take a short break in between flights to cool my brain down.
2017-9-23
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MorganLeFay
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Blue Ridge Big  Posted at 2017-9-23 13:37
I have found that my aircraft flies better if I take a short break in between flights to cool my brain down.

Yes definitely.
IMHO that is.


2017-9-23
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MorganLeFay
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Labroides Posted at 2017-9-22 22:26
DJI have run drones for 72 hrs continuously.
There's no need for any cool-down between flights.

Thank you very much. That is good to know!
2017-9-23
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MorganLeFay
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TYVM to all who offered feedback on this question!! I am new to brushless motor drones. It appears they do not have an overheating problem. My continuous flying times are approximately 1.25 hours (3 batteries).
  My P4P motors ran at a max of 98F in an 88F Sunny day(Temps are taken Immediately after the 25min flight). All other readings were less and seemed to indicate a 10F to a MAX 15F Delta T. The Batteries show a much higher temperature as expected. I am ordering a fourth battery for added flying time.
2017-11-3
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