Does anyone have any info/experience on what is the optimum/most economical speed vs batt life for a P3P? For example at 90 in my car I am burning more fuel per mile than at 60...
For instance, if I were to plan a mission on Litchi mission planner, say at 30 mph, I would expect a shorter flight time than at 20 mph, however it would take longer to complete the mission at 20 mph. There must be a sweet spot in there somewhere for max distance vs batt life...
Thx!
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I think I can figure this out with some more work and more analysis.
During the flight:
1) Speed is a function of time. s(t)
2) Distance traveled d(t) is the integral of the speed s(t) with respect to time t. (I can't type integral math symbols here)
3) Battery current is a function of time i(t)
4) Amp hours used out of the battery is the integral of current i(t) with respect to time t.
5) The capacity of the P3P battery is a constant = 4.48 Amp-Hours
6) We should plot speed s(t) on the vertical axis, and current i(t) on the horizontal axis.
7) There is a max speed S, and there is a max current I. Plot this point on our graph.
8) If you draw a straight line from the origin (0,0) to S,I then any combination (speed, current) along this line will give the same maximum distance by the time the battery capacity is consumed.
9) Note that in a hover the speed s(t) = 0 , but the current i(t) is not zero. Plot this point on our graph.
10) Now draw a dotted and curved line from the hover point to the maximum point S,I Should the dotted line be drawn concave up or concave down? My experience with physics tells me to expect the dotted line will be concave down, and thus the dotted line will go above the straight line. When the raw data of s(t) and i(t) is measured and plotted, we will know for sure if it is concave down.
11) The optimum speed for longest distance will be where the vertical (speed) difference between the dotted line and the straight line reaches a maximum. Once we have the curves plotted we can calculate this maximum.
Note that we need to find a way to measure the battery current i(t) during the flight and save it with the rest of the data for each flight.
Maybe DJI will do that for us and save i(t) in the txt, csv (excel) file.
This is my first thoughts on the problem after thinking about how to solve it for about an hour.
Maybe this will get some of you guys/gals thinking about this problem too.
Keep the shinny side up,
Joe
KC7GHT