Why Did Mavic 2 Use 60% of Its Power on the Return With Slight Tailwind?

[jelarv]

I just flew a 5.3 mile run with my Mavic 2 and almost ran out of power unexpectedly. When I do a distance run I always turn back when the battery has at least 60% left, which usually leaves me with 10%-15% to spare. But this time I was down to 1% and I had a slight tailwind on the return (I had plenty of places to land early because it's out in the country, but thankfully got back to my starting point). Put another way, why would the Mavic 2 require 60% of the power for half the trip other than due to a headwind? I didn't do anything special with the camera in either direction.

Somewhat related, it shows I used 22.75 minutes of battery time and it's only a month old. I was traveling about 30 mph which I've read is close to the optimal speed to maximize distance. Any thoughts why it wasn't closer to the stated 31 minutes (which I don't expect to get 100%)).

 

[brett8883]

I just flew a 5.3 mile run with my Mavic 2 and almost ran out of power unexpectedly. When I do a distance run I always turn back when the battery has at least 60% left, which usually leaves me with 10%-15% to spare. But this time I was down to 1% and I had a slight tailwind on the return (I had plenty of places to land early because it's out in the country, but thankfully got back to my starting point). Put another way, why would the Mavic 2 require 60% of the power for half the trip other than due to a headwind? I didn't do anything special with the camera in either direction.

Somewhat related, it shows I used 22.75 minutes of battery time and it's only a month old. I was traveling about 30 mph which I've read is close to the optimal speed to maximize distance. Any thoughts why it wasn't closer to the stated 31 minutes (which I don't expect to get 100%)).

You’ll have to upload your flight log

 

[Juggler]

maybe at the drones altitude the wind was different

 

[jelarv]

maybe at the drones altitude the wind was different

Excellent point Juggler! I thought the drone was making real good time on the outbound leg which makes me think at 400 feet it might have had a tailwind (headwind on the return) which was opposite of what I was feeling on the ground and what shows on the NWS as surface wind. With that said, I just went to earth :: a global map of wind, weather, and ocean conditions and it's consistent with the NWS at the surface and at 1,000 hPa and 850 hPA which is the range where I would have been flying.

 

[Juggler]

Excellent point Juggler! I thought the drone was making real good time on the outbound leg which makes me think at 400 feet it might have had a tailwind (headwind on the return) which was opposite of what I was feeling on the ground and what shows on the NWS as surface wind. With that said, I just went to earth :: a global map of wind, weather, and ocean conditions and it's consistent with the NWS at the surface and at 1,000 hPa and 850 hPA which is the range where I would have been flying.

Maybe this forecast might explain it...

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[Brockrock]

Excellent point Juggler! I thought the drone was making real good time on the outbound leg which makes me think at 400 feet it might have had a tailwind (headwind on the return) which was opposite of what I was feeling on the ground and what shows on the NWS as surface wind. With that said, I just went to earth :: a global map of wind, weather, and ocean conditions and it's consistent with the NWS at the surface and at 1,000 hPa and 850 hPA which is the range where I would have been flying.

I do lots of distance flights with my M2P, and I love flying during windy conditions and using them to my advantage. I always fly into the wind outbound and typically stay as low as I can and then climb higher on the return in order to catch the higher velocity tailwind back home. Wind directions can certainly vary however based on altitude, although this is usually due to some passing weather phenomenon versus the general airflow in a certain area. One thing to keep an eye on is the little attitude indicator icon which shows the bank angle of the copter. The more 'sky' that is showing on the top, the more the copter is banked forward bucking the wind. The goal is to have as little sky showing as possible at that magic 30 MPH which means the copter is working less to maintain that speed. Fly safe!

 

[jelarv]

I do lots of distance flights with my M2P, and I love flying during windy conditions and using them to my advantage. I always fly into the wind outbound and typically stay as low as I can and then climb higher on the return in order to catch the higher velocity tailwind back home. Wind directions can certainly vary however based on altitude, although this is usually due to some passing weather phenomenon versus the general airflow in a certain area. One thing to keep an eye on is the little attitude indicator icon which shows the bank angle of the copter. The more 'sky' that is showing on the top, the more the copter is banked forward bucking the wind. The goal is to have as little sky showing as possible at that magic 30 MPH which means the copter is working less to maintain that speed. Fly safe!

Brockrock, thanks so much! I received a new battery just last yesterday and plan to do a distance run today...I'll give your strategy a try. What's your best distance? I've seen others on YouTube get 6 miles (each way) but the run above was only 5.3 miles and my battery was a 0% when it landed.

 

[Brockrock]

Brockrock, thanks so much! I received a new battery just last yesterday and plan to do a distance run today...I'll give your strategy a try. What's your best distance? I've seen others on YouTube get 6 miles (each way) but the run above was only 5.3 miles and my battery was a 0% when it landed.

How does the ol' saying go, "Ask me no questions, I'll tell you no lies":..?... What I can say is that I do all of my distance flights strictly over water.

This was not a record breaker by any means, but an example of the areas where I fly -

 

[Meta4]

Any thoughts why it wasn't closer to the stated 31 minutes (which I don't expect to get 100%)

All anyone can do is guess without seeing the actual flight data which will show exactly what was happening.

 

[Sandpiper270]

A common phenomenon that may be related to your flight is that the wind can be expected to change about 30 degrees as you get close to the surface. It is briefly explained here: Key Skill: Determining Wind Direction | METEO 3: Introductory Meteorology
What is happening is that the wind aloft flows parallel to the isobars, it is not going across them from high to low pressure. But as you near the surface you get drag, and that slows the wind. When that happens the wind does flow across the isobars, they say at about 30 degrees. So you could expect a 30 degree difference in wind direction as you move vertically, and the difference depends on the amount of surface drag. I think you would find it mentioned in a private pilot training book.

 

[Sandpiper270]

Somewhat related, it shows I used 22.75 minutes of battery time and it's only a month old. I was traveling about 30 mph which I've read is close to the optimal speed to maximize distance. Any thoughts why it wasn't closer to the stated 31 minutes (which I don't expect to get 100%)).

Different speeds for different things. In your car you would not expect the speed that gets you some place the fastest to also be the speed the lets your car run for the longest amount of time. Seems I have read that the maximum flying time for the drone was measured at 17 mph. The speed to travel the greatest distance I assume is closer to the speed you flew.

 

[Meta4]

Different speeds for different things. In your car you would not expect the speed that gets you some place the fastest to also be the speed the lets your car run for the longest amount of time. Seems I have read that the maximum flying time for the drone was measured at 17 mph. The speed to travel the greatest distance I assume is closer to the speed you flew.

Pretty close ... DJI spell it out in the specs:

Max Flight Time (no wind)	31 minutes (at a consistent 25 kph)
Max Hovering Time (no wind)	29 minutes
Max Flight Distance (no wind)	18 km (at a consistent 50 kph)

25 km/hr = 15.5 mph

 

[Sandpiper270]

Pretty close ... DJI spell it out in the specs:

Max Flight Time (no wind)	31 minutes (at a consistent 25 kph)
Max Hovering Time (no wind)	29 minutes
Max Flight Distance (no wind)	18 km (at a consistent 50 kph)

25 km/hr = 15.5 mph

Calculating the time for Max distance I get 21.6 minutes. Indicates to me the battery is good getting over 22 minutes.