6 flights at 50% on the batteries.....enough ??

[GadgetGuy]

I myself haven't heard that or remember reading that, I do hover around close to me and low to help run it down, I would say 20% or so and then let it sit to the other 8%, it doesn't seem to take too long.

But you have brought up a point I'm not sure so maybe someone will give input on that. Good question BTW!

When the power is on while the motors are off, I have noticed that the gimbal quickly overheats. This also happens during firmware updates and IMU calibration. I overcome this by blowing a fan at the aircraft. I would recommend doing the same, while running the battery down without the props spinning, during their 8% reset. The gimbal is air cooled during flight, much like a motorcycle, and if not moving, it can overheat, without air circulating around it.

 

[GadgetGuy]

I put mine on the bench, take the props off and let it idle down to 8 %.. I put a small electric fan blowing on the P3 while it is discharging, keeps everything cool.

Great minds think alike! You beat me to it!

 

[bobmyers]

Great minds think alike! You beat me to it!

Got that suggestion from another lad on this forum a a couple of months ago. Just passing it on.

 

[Jbundy63]

I put mine on the bench, take the props off and let it idle down to 8 %.. I put a small electric fan blowing on the P3 while it is discharging, keeps everything cool.

When the power is on while the motors are off, I have noticed that the gimbal quickly overheats. This also happens during firmware updates and IMU calibration. I overcome this by blowing a fan at the aircraft. I would recommend doing the same, while running the battery down without the props spinning, during their 8% reset. The gimbal is air cooled during flight, much like a motorcycle, and if not moving, it can overheat, without air circulating around it.

Thanks to both, good info and will do, makes a lot of sense. As well to
CONTROL FREQ... Thanks for bringing that question up!

 

[GadgetGuy]

With regard to running the motors the remaining maH is the key to the P3 motors stopping -- at 30% there should be approximately 1250 maH remaining out of a possible 4450 (max charge) and the cell voltages will be around 3.7 with no motor load-- down to about 3.6 under full load. Drain them down to 8% under load and you are very close to falling under 3.0 volts per cell and under if you are at full throttle trying to keep it from crashing.

You can dice it, slice it, cut it and chopped it any way your want -- but it all means the same-- at 10% the P3 is out of gas -- gravity will take over and there is a good chance that the battery will be damaged either by the crash or by cell damage caused by trying to keep the thing from crashing in the wrong place.

Thank you for the clarification. Good points! Duly noted! My goal is to always handcatch before Autoland kicks in at 10%. Reaching 10% in flight is a very dangerous condition all around, and best avoided! With the battery mod, after landing, one still has to first disconnect the external batteries before turning off the internal battery. This usually takes 30 seconds or so, so the battery may drop below 10% with no load on it during that shutdown. I also immediately remove the internal battery to prevent internal heat build up, and to start the cooling process, prior to recharging.

 

[GadgetGuy]

Got that suggestion from another lad on this forum a a couple of months ago. Just passing it on.

Paying it forward! We all learn from each other! Collective wisdom!

 

[GadgetGuy]

@bobmyers : Just checked individual cell voltages this evening after a long flight and at 14% remaining power on the internal battery, it was still reporting 3.69 volts on the lowest cell, so I sincerely doubt that 8%, even under load, would take it to anywhere close to 3.0 volts or under. You were suggesting these readings should be present at a mere 30% remaining battery power. Do I just have a really good battery, or are we being very generous in how quickly the voltage is depleted? Even at 6% remaining on two rare occasions, neither external 1600 or 2800 ever dropped below 3.69 volts per cell when beginning recharging immediately after. I'll keep checking. I certainly don't want to damage them, and don't deliberately do this, but the results appear to not be quite as dire as you predicted, at least in terms of the voltage remaining, at such low levels of remaining battery percentage.

 

[gkol]

Guys! We have 2015, these are modern Lipos - they do not need any sort of preparation before use. It's a myth! I have 4 batteries each >40 flights and all of them have 100% health. I have never done any 50% suff. The best thing to do is not to go under 20-25% every flight and that's the key to good health of cells.

 

[videcom]

I fly until I get the 30% warning then bring her home. I only fly line of sight so not too long to get back. Charge back up until third light flashes to store battery.

 

[bobmyers]

@bobmyers : Just checked individual cell voltages this evening after a long flight and at 14% remaining power on the internal battery, it was still reporting 3.69 volts on the lowest cell, so I sincerely doubt that 8%, even under load, would take it to anywhere close to 3.0 volts or under. You were suggesting these readings should be present at a mere 30% remaining battery power. Do I just have a really good battery, or are we being very generous in how quickly the voltage is depleted? Even at 6% remaining on two rare occasions, neither external 1600 or 2800 ever dropped below 3.69 volts per cell when beginning recharging immediately after. I'll keep checking. I certainly don't want to damage them, and don't deliberately do this, but the results appear to not be quite as dire as you predicted, at least in terms of the voltage remaining, at such low levels of remaining battery percentage.

Thanks for the info...

Yes, I noticed the same thing when I was deep cycling three of mine they got down to 3.63 per cell under minimum load at 8%. So if the cells are balanced, I would assume that there would be .6 volts per cell cushion to the 3 Volt mark. If there was one week cell and they were significantly out of balance-- one week cell could be an issue. When I did accelerate the motors briefly That reading went below 3.63 and the lowest cell at 3.48 turned red until I released the throttle and then they equalized again at 3.61 and 3.62.

Appreciate the info-- so the question remains-- can you run it down to 3.0 volts?-- with this test I would have to say no- because the motor would shut off before it reached 3.0 volts. You could run it down to 3 volts by leaving it on, which probably happens with one is lost or lands due to low batter.

I am not going to discharge a good battery to find out and don't think I need to if these tests are correct. Would be nice if DJI would put out the telemetry limits so all this does not have to be self test. I am sure they already know all of this info.

 

[RedHotPoker]

Got that suggestion from another lad on this forum a a couple of months ago. Just passing it on.

Yeah, my double fan that can be tilted up, still works well for keeping things cool during charging phases. Holds both my 100w chargers and two intelligent flight batteries, or I can set the Phantom on one side and let it run, with the radio controller on the other side, chilled.
There is no reason to have your Phantom 3 overheat while you are utilizing the iOS SIM either, just place it on the fan while you fly on the SIM. A fan, keeps the cool air circulation, flowing moderately strong.

RedHotPoker