Battery temperature in drone

[Aus1]

The temperature specifications quoted in user manual is that the maximum flying temperature is 40ºC. I have found no references as to whether this is ambient temperature or drone battery temperature, as there is a large difference. I have attached a thermal photo of the battery and drone body temperature when I was flying on a day of about 38ºC, and the battery temperature was well in excess of battery manufacturer specifications. If I keep the battery temperature within manufacturer specifications then I cannot send the drone up at anything above 30ºC. Has anyone else looked at this problem.

 

[zeusfl]

My personal hottest battery flight was archived by my MA2 in August (I live in Florida) and was 58.61 (the battery)
Airdata have this information. How accurate is your instrument readings?

You are 10 degrees over my hottest battery. Not sure how hot will be the drone since the drone has fans to cooldown the board. This can explain the difference in temperature since the battery depend from the air to cooldown, but the direct sun of Florida does not help.

 

[Aus1]

I fly in Australia and the summers are getting hotter here - almost too hot to go outside. Last summer we had a week with every day over 40ºC (105F). I checked the thermal photo and the drone body internals were about 5ºC cooler. The thermal camera is reasonably accurate as it measures the boiling temperature of water correctly. Yesterday was a warm 33º and the battery temperature indicated 50+ on the screen - did not get out the thermal camera.

 

[Thomas B]

My rule in Phoenix area is not to fly if ambient temp is 104 degrees F or more. This has served me w/o incident on my MPP or M2P for over 2 years.
Your mileage may vary.

 

[Aus1]

I have been flying the Mavic for over 2.5 years now and still have the original pair of batteries so they seem to cope surprisingly well with exceeding manufacturer specs on occasions. One thing I have routinely done when the battery is obviously hot is to remove the battery from the body to let it and the drone cool off more quickly.

 

[SmilingOgre]

60°C is often quoted as the upper limit for a LiPo although damage can occur at that temp.

 

[Meta4]

The temperature specifications quoted in user manual is that the maximum flying temperature is 40ºC. ... If I keep the battery temperature within manufacturer specifications then I cannot send the drone up at anything above 30ºC. Has anyone else looked at this problem.

Problem? Relax .. it's not a problem.
Your batteries are delivering a lot of current and that can't happen without raising the temperature.
The temperature range mentioned in the specs is the environmental operating temperature.
It's not the temperature of the battery.

 

[Aus1]

Yes, I would have thought that 60ºC would be an acceptable upper limit. Does anyone (from DJI ?) know what the specifications are for the batteries that DJI uses. There must be someone who at least knows the battery brand and model number of the batteries that are used in the DJI battery packs.

 

[Meta4]

Yes, I would have thought that 60ºC would be an acceptable upper limit. Does anyone (from DJI ?) know what the specifications are for the batteries that DJI uses. There must be someone who at least knows the battery brand and model number of the batteries that are used in the DJI battery packs.

Your batteries get hot, everyone's batteries get hot.
It's normal.
That's how batteries work.

 

[Aus1]

Your batteries get hot, everyone's batteries get hot.
It's normal.
That's how batteries work.

A technical correction seems needed here. Batteries do not work by getting hot, they work by providing electric current from the chemicals within the battery to a load (motor). The heat is a waste product created by the electric current encountering a variety of low value resistances within the structure of the battery, wiring connections and the wiring itself. In a brand new battery about 10% of the energy coming from the chemistry will end up being wasted as heat and the motor gets the remaining 90%, while for a cheap (or older) battery up to 30% of that energy may be lost as heat and the motor gets what is left. That difference is seen as a loss in performance of the drone, and a hotter battery.

 

[Meta4]

A technical correction seems needed here. Batteries do not work by getting hot, they work by providing electric current from the chemicals within the battery to a load (motor). The heat is a waste product created by the electric current encountering a variety of low value resistances within the structure of the battery, wiring connections and the wiring itself. In a brand new battery about 10% of the energy coming from the chemistry will end up being wasted as heat and the motor gets the remaining 90%, while for a cheap (or older) battery up to 30% of that energy may be lost as heat and the motor gets what is left. That difference is seen as a loss in performance of the drone, and a hotter battery.

That's what I said ... run all that current from your battery to the motors and the battery gets hot.
That's why DJI's larger drones are ventilated with a fan driving air through a series of holes that run through the battery.
Yours is getting hot just like everyone else's does.

 

[Aus1]

That's what I said ... run all that current from your battery to the motors and the battery gets hot.
That's why DJI's larger drones are ventilated with a fan driving air through a series of holes that run through the battery.
Yours is getting hot just like everyone else's does.

With my original post I was questioning whether DJI were referring to ambient temperature or drone operating temperature. I was not questioning why batteries get hot - they get hot because of internal resistances. You earlier comment of "That's how batteries work" seemed to imply that batteries had to get hot so they could work, which is certainly not the situation. If the internal resistance of a battery pack was 0.0 ohms then the battery would stay at ambient temperature when working and 100% of the energy would go the making the drone fly, rather than be wasted in heat, and no cooling fans would be needed either.

 

[Meta4]

With my original post I was questioning whether DJI were referring to ambient temperature or drone operating temperature.

And that was answered for you in post #7

I was not questioning why batteries get hot

But that's the way the whole discussion went

If the internal resistance of a battery pack was 0.0 ohms then the battery would stay at ambient temperature when working and 100% of the energy would go the making the drone fly, rather than be wasted in heat, and no cooling fans would be needed either.

But the internal resistance isn't zero ohms and DJI batteries get quite hot when they are running.

 

[zeusfl]

There is not batteries with an IR of 0. The higher quality is the pack, the lower IR will have. This is common in R/C Helicopter community. The higher Rated C, the less heat the battery produce. If DJI use a better battery components can lower the heat, but is not necessary since the system is made to handle it. Anyway the DJI batteries are already good quality (probably not the best) but good. This is the difference from buying after market cheap batteries. They will do the work for the first month and eventually will decrease the capacity and the Internal Resistance will be higher and higher unbalanced by cells.

 

[wingbotics]

This is very true. My experiences so far indicated with my logger monitoring most of my flies that:

1. Mavic Pro OEM battery is about 51C after about 20 minutes of flying.
2. The after market battery is about 59C after about the same amount of time flying.

They are almost 10C difference.

 

[Conservative Nihilist]

Wow. An operating temperature differential of ten degrees, between the OEM batteries, and their after-market variants, is massive. On a really hot day, such a temperature rise with a non-standard battery, could spell the difference between a routine flight, and Aaaaargh !

All the same, I have used non OEM batteries with my P3S for many flight hours without experiencing any temperature related mishaps thus far, knock on wood.