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Flight Distance Comparison with Hi-Cap Battery
492 9 2017-5-19
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BearDrone
lvl.4
Flight distance : 2887251 ft
United States
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I ordered a high capacity battery a couple of weeks ago, and I have had it in rotation with the standard one that came with my P4. My longest flight in distance has been with this hi-cap battery at 39,003 ft. with a time of 25:09, 18% charge left on the battery. This was at sea level on a pretty calm day flying over the Atlantic.

Today, I had another flight with the same battery of 28,938 ft. with a time of 23:43, 18% charge left on the battery, also flying in another calm day basically over estuaries and waterways.

That is a difference of 10,065 ft., on what, at least in my mind, should be the same parameters for the battery performance. Why such a huge difference in the distance traveled?

If it is wind, wouldn't you argue that if you had a 8 mph headwind on the way out, you would recoup any expended energy on the way back?

Both days the wind was under 10 mph, and even lighter if you ask me. I'm just wondering what could explain the difference.

Thanks in advance for comments.
2017-5-19
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Geebax
Captain
Australia
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The flaw in your theory is that flying with a tailwind does not put charge back in the battery. In any wind, the aircraft is having to work harder to go where you want it to go, and that translates to lost battery energy.
2017-5-19
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BearDrone
lvl.4
Flight distance : 2887251 ft
United States
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Geebax Posted at 2017-5-19 14:35
The flaw in your theory is that flying with a tailwind does not put charge back in the battery. In any wind, the aircraft is having to work harder to go where you want it to go, and that translates to lost battery energy.

Of course a tailwind does not put current back in my battery. However, it does increase the speed at which distance is traveled given the same current drain of the battery.

My point was that all thing being equal, including the wind conditions during the two discrepant flights, what could explain a almost 25% difference in the distance traveled on what appears to be two very similar battery performances?
2017-5-19
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Nigel_
Captain
Flight distance : 388642 ft
United Kingdom
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What if the wind is from the side, then you have to fly against it both on the way out and on the way back!

Also, remember that the best fuel economy on the Phantom is at around 29mph, just hovering not only get less miles per KWh but also gets less flight time.
2017-5-19
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BearDrone
lvl.4
Flight distance : 2887251 ft
United States
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Nigel_ Posted at 2017-5-19 14:57
What if the wind is from the side, then you have to fly against it both on the way out and on the way back!

Also, remember that the best fuel economy on the Phantom is at around 29mph, just hovering not only get less miles per KWh but also gets less flight time.

Nigel,

Yes, you are right about crosswinds and the variability of the variable of wind!!

Let me ask you this; when I am on the forward throttle all the way, I can only get to about 22 mph in windless conditions. How are you getting a steady 29mph? That would certainly increase my traveled distance,  I would think.

On both these flights, I was testing for distance traveled. I was moving and not hovering or trying to do slow turns for video, etc. I wanted to see how far I could get out of one battery charge from point A to B.
2017-5-19
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Labroides
Captain
Flight distance : 9991457 ft
Australia
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BearDrone Posted at 2017-5-19 15:10
Nigel,

Yes, you are right about crosswinds and the variability of the variable of wind!!

If you turn off Obstacle avoidance, you will gain a big speed boost and if you are flying at sea, you don't need OA.

"My point was that all thing being equal"
The thing is that once you go to the outdoor laboratory and have a human at the controls, it's very hard to have all things equal.
Another point to consider is firmware.
Did you have the same firmware versions for the two flights?
Some users are complaining that recent firmware changed the way the Phantom deals with tailwinds, maintaining speed rather than allowing a tailwind assist.
(I haven't checked myself so can't tell if this is happening)
2017-5-19
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BearDrone
lvl.4
Flight distance : 2887251 ft
United States
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Labroides Posted at 2017-5-19 16:33
If you turn off Obstacle avoidance, you will gain a big speed boost and if you are flying at sea, you don't need OA.

"My point was that all thing being equal"

Thanks for the tip on disabling obstacle avoidance. I'll give that a try.
As for firmware, I'm not sure of that. I do know that I did get a message that wanted me to do a firmware update because some 'modules' were incompatible. It only took about 30 seconds and it was suggested to me that this was a firmware update for the new high capacity battery that I was using.
Maybe that did come into play somehow.
2017-5-19
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BearDrone
lvl.4
Flight distance : 2887251 ft
United States
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Labroides Posted at 2017-5-19 16:33
If you turn off Obstacle avoidance, you will gain a big speed boost and if you are flying at sea, you don't need OA.

"My point was that all thing being equal"

Thanks for the tip on disabling obstacle avoidance. I'll give that a try.
As for firmware, I'm not sure of that. I do know that I did get a message that wanted me to do a firmware update because some 'modules' were incompatible. It only took about 30 seconds and it was suggested to me that this was a firmware update for the new high capacity battery that I was using.
Maybe that did come into play somehow.
2017-5-19
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Labroides
Captain
Flight distance : 9991457 ft
Australia
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BearDrone Posted at 2017-5-19 17:35
Thanks for the tip on disabling obstacle avoidance. I'll give that a try.
As for firmware, I'm not sure of that. I do know that I did get a message that wanted me to do a firmware update because some 'modules' were incompatible. It only took about 30 seconds and it was suggested to me that this was a firmware update for the new high capacity battery that I was using.
Maybe that did come into play somehow.

Battery firmware won't make any difference.
What I was referring to was reports that previous firmware allowed your Phantom to get a speed boost from a tailwind in P-GPS mode.
According to some, recent firmware regulates your speed so that even with a tailwind it will not exceed the speeds in the specs.
I don't know if this is true but it might be as a similar thing happened back in the P3 days.
2017-5-19
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Mobilcams
First Officer
Flight distance : 2907674 ft
United States
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Labroides Posted at 2017-5-19 18:37
Battery firmware won't make any difference.
What I was referring to was reports that previous firmware allowed your Phantom to get a speed boost from a tailwind in P-GPS mode.
According to some, recent firmware regulates your speed so that even with a tailwind it will not exceed the speeds in the specs.

I have noticed this speed regulation on the P4P, but not the P4.  I might now update anything else after the next Go and firmware update come out..I am a little scared after the last message they put out :/
2017-5-19
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