Battery usage/conservation question

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Today I flew out 2.5 Mi over Water to try to photograph a bridge. I went in sport mode which took me out there at 44 miles per hour. By the time I got out there to take the pictures I got a low battery warning and a forced return to home. Would I have been better off to go out in standard mode at about 22 miles an hour? Would this have given me more time to take pictures? As it turned out I still had 35% battery when the Drone return back to me. Is there any sort of a direct relationship of speed to battery conservation?
Thanks
Dennis
 

Meta4

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Today I flew out 2.5 Mi over Water to try to photograph a bridge. I went in sport mode which took me out there at 44 miles per hour. By the time I got out there to take the pictures I got a low battery warning and a forced return to home. Would I have been better off to go out in standard mode at about 22 miles an hour? Would this have given me more time to take pictures? As it turned out I still had 35% battery when the Drone return back to me. Is there any sort of a direct relationship of speed to battery conservation?
Sport Mode is like driving your car at 90 mph.
You go fast but burn a lot of fuel quickly.
When you are wanting to get good mpg with the Phantom, disable obstacle avoidance in the app and fly at full speed in P-GPS mode.
You should get about 35-36 mph in still air and the best fuel economy.
 
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One key factor that many people forget is wind.... both wind direction and wind speed.

When making a long distance run you need to research it carefully because it's possible you went OUT with a headwind and came back IN with a tailwind which is EXACTLY what you should do. This gives you the best chance for a successful return.

If you do it the other way (tail wind out and head wind back) and you turn around at the Return to Home Battery level you probably wouldn't have had enough to make it home.
 
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Sport Mode is like driving your car at 90 mph.
You go fast but burn a lot of fuel quickly.
When you are wanting to get good mpg with the Phantom, disable obstacle avoidance in the app and fly at full speed in P-GPS mode.
You should get about 35-36 mph in still air and the best fuel economy.
I tried your method today and it work to some extent. I flew out at about 32 miles an hour in a very light headwind and was able to photograph for about 5 to 6 minutes. More than yesterday for certain. When I got the alert for a low battery I came back and today I had about 4 extra minutes battery compared to yesterday at about 42%.
Regards
 
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You’ve been at this longer than me, but at 2.5 miles out you cannot be vlos with your bird. Try to position yourself closer to your target and you’ll not have to worry about battery or time or breaking any regulations, Be Safe, Fly Safe.
 
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There are two things to bear in mind when 'driving' an electric motor :

1. Amp rate that is due to the command you give the model. This is NOT linear against throttle position. The rate of increase of amp rate increases as you give more throttle.

2. When drawing low amp rate - you have apparently more capacity to use. When drawing high amp rate - you apparently have less. This is because resistance to supply power internally of the battery increases with amp increase. This causes more voltage drop - which then causes increased amps to maintain watts demand.

For best use of battery power - its actually less than full throttle to avoid #2 .... if I am going for distance - I usually reduce my throttle to about 70 - 75% to try and take advantage of #2.
 
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There are two things to bear in mind when 'driving' an electric motor :

1. Amp rate that is due to the command you give the model. This is NOT linear against throttle position. The rate of increase of amp rate increases as you give more throttle.

2. When drawing low amp rate - you have apparently more capacity to use. When drawing high amp rate - you apparently have less. This is because resistance to supply power internally of the battery increases with amp increase. This causes more voltage drop - which then causes increased amps to maintain watts demand.

For best use of battery power - its actually less than full throttle to avoid #2 .... if I am going for distance - I usually reduce my throttle to about 70 - 75% to try and take advantage of #2.

Would this be dependant on which mode I used to get out there?

I did do what Meta4 suggested and turn off all sensors and it did bump up my speed in P mode to over 30 mph.

Dennis
 
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Would this be dependant on which mode I used to get out there?

I did do what Meta4 suggested and turn off all sensors and it did bump up my speed in P mode to over 30 mph.

Dennis
Of course mode and what is powered will make difference ...

Its like driving a car and trying to get best mileage out of a gallon of petrol. Turn off the AC ... radio ... all things taking electrical power and causing alternator to draw on the engine etc. - This is like switching off sensors on your P3 / P4 - reduces load on battery ... every mA counts.

Next is choosing right gear and throttle to maximise efficient use of the fuel used .... that's like you choosing right mode to fly and throttle setting.

Throttle use and efficient cruise setting is NOT dependent on mode used - basically the motors have their specific RPM per prop used most efficient level ... and as I said - it can be in that 70 - 75% range.


But lets not get too out of touch with this ... temperature, wind, how you use throttle (aggressively or with due thought) .... many factors can negate the benefits above ... but on average the above will help.
 

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Its like driving a car and trying to get best mileage out of a gallon of petrol. Turn off the AC ... radio ... all things taking electrical power and causing alternator to draw on the engine etc. -
This is like switching off sensors on your P3 / P4 - reduces load on battery ... every mA counts.
There are things that matter and other things that are too trivial to be concerned with.
Turning off the radio in your car won't make a measureable difference.
The power use by the sensors is negligible.
But having the obstacle avoidance enabled limits the tilt angle of the drone so that OA can work properly.
That's great for OA but it significantly limits top speed.
 
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I don't want to turn this into a BVLOS debate. I am a proponent of staying within VLOS at all times. But I am curious about two things and would truly like to be enlightened.

1. When you go that far out, how do you determine if you have a headwind or tailwind? And cant that change at various points (and elevations) in the mission?

2. When flying BVLOS, isn't turning Obsticle Avoidance off a little scary (if not unsafe)?

Beautiful picture by the way!
 

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1. When you go that far out, how do you determine if you have a headwind or tailwind? And cant that change at various points (and elevations) in the mission?
Before you head off into the distance, you always need to understand what the wind is doing and how that is likely to affect your flight.
You should be able to judge wind speed and direction at your flying location by observing trees, flags, waves etc and feeling the wind on your face.
If the direction and strength cause concern but you aren't sure, you can simply put the drone up and try flying into the wind and see how much that affects your speed.
You know how fast your drone goes in still air (16 metres/sec with OA disabled).
If you can only fly at 5 m/s against the wind, that means you could fly a short distance away and get back slowly but would have a hard time returning against the wind over a significant distance.
And/or you can observe how your drone hovers in the wind.
If it can't hold position, you don't want to go far from home at all.
You also need to understand that winds higher up will be blowing stronger.

2. When flying BVLOS, isn't turning Obsticle Avoidance off a little scary (if not unsafe)?
It doesn't matter how far or close the drone is, you always need to be aware of the flying environment and what obstacles are present.
Obstacles are involved in most crashes.
It's very hard to get into trouble when there's nothing to hit.
If you fly over the sea or open country at a height where there are no obstacles to worry about, it's pointless bearing the significant speed (and range) reduction that obstacle avoidance puts on you.

And generally if you think you need OA, you'd be better off flying further away from the obstacles that are scaring you.
 
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1. When you go that far out, how do you determine if you have a headwind or tailwind? And cant that change at various points (and elevations) in the mission?
I use an app to determine the wind velocity and direction and any altitude before launching. I have android and it's available on the playstore.
2. When flying BVLOS, isn't turning Obstacle Avoidance off a little scary (if not unsafe)?
This was answered above. Just use a lot of common sense. Turning OA on and off once at your goal is fast and easy.
 
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