Battery drain at idle?

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Hi All. I have an assignment to film a school bus arriving at an education center and dropping off students tomorrow morning. My problem is going to be timing. The bus is supposed to arrive at 9am, but I know the unpredictably of Long Island rush hour traffic and that estimated 9am arrival time can vary by a good 15 minutes on either side of that. I generally use the Litchi software, and I will need to turn the drone on prior to bus arrival so I can connect wifi (sometimes can be a bit defiant), make sure video and telemetry feed is good, and set the home point. So as not to burn out the wifi unit while sitting and waiting for the bus to approach, I feel it will be necessary to have the props spinning at idle to help cool the unit -- even though I have done the heat sink upgrade to it and have also opened the shell vent holes wider. Aside from the wifi unit overheating, my other concern is battery drain while I wait for the bus with props idling. I assume the drain isn't as quick as when flying/hovering, but I I'm thinking I could be idling on the ground for a good 10 minutes. I have arranged for the teacher assistant to text me (don't worry, I use a tablet to fly) when the bus reaches two points along it's route -- the first for me to start setting up and the second for me to to launch when they are reasonably close. Morning temp will probably be upper 70s.

Can anyone guess how much concern I should have regarding the wifi overheating and also battery drain while idling on the ground? Thanks.
 
Overthinking it.

Have you ever played with the flight simulator for an hour? Drone has to be on (idling) the entire time to use it, even to the point the internal fan kicks on. I've had mine on for a long time outside in the heat while fiddling with the camera shooting stills without an issue with the props off. When the motors are spinning and active is when it begins to drain rapidly.
 
Okay, possibly overthinking. But I'm talking about a P2V+ v2. Haven't run the simulator because it hasn't got one. Also no internal cooling fan or holes in the wifi unit. Luckily, if the timing doesn't work out this morning, the shoot isn't critical. It's for marketing materials for a non-profit that my firm supports. There will be future class field trips to the Center and I'll have other opportunities to try this again if the timing doesn't work out today. Thanks for the feedback, GMack. I appreciate it.
 
Also, having the motors running to cool the unit is likely a net loss thermally. I don't believe they provide any significant internal cooling and only serve to generate more heat than they could reduce.

Any way to be cued as to the arrival time by a passenger, student, chaperone, texting you, etc?
 
THE RESULT: A not a very successful filming attempt. I did get updates via text regarding the anticipated arrival time of the bus as well as key locations of the bus while en route. I established my launch location in a large parking lot, which turned out to be about 200 yards from where the bus ultimately let the students off. (Closer would have been preferred, but I chose a wide open landing spot to avoid the dense brush in the area. I had decided not to turn the Phantom on until final approach of the bus to conserve the battery's full charge because I knew I would not have time to fly back and change out the battery midway through the shoot. I flew over to the parked bus at an altitude of 70 ft and hovered.. and hovered.. for at least 5 minutes with no one coming off the bus. Then the bus moved a short distance and parked again. I hovered for another 5 or so minutes (as Litchi read off the declining battery charge). FINALLY, students began coming off the bus only to mill about for another 3 minutes instead of lining up for the walk to the building. 20% battery warning and Litchi tells me it is about to Auto Return, so I abort that (I don't like relying on it) and figure I can just fly the relatively short distance back on my own - and with a slight breeze helping me home. As soon as I start heading back, Litchi reports that my battery is now critically low at 7% (Whhaaaaat!??) and begins to auto land. I moved laterally, aimed for an asphalt walkway, and put her down just in the nick of time as there is not much descent time from only 70 ft. I still have to review the video, but I suspect this is going to turn out to be just a practice run for me. Nice morning to fly, though.
 

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