Recreated "falling from the sky" issue

Balance charging is different. The deep discharge serves to make sure the firmware know the upper and lower limits of the battery. If the battery us always only taken down to 30% there is the possibility that the firmware will make an error and now think that 30% is (effectively) 0%. So you'd really be running the battery from 100% down to 60% and not 30%. Charging each cell up equally is something totally different.
From firmware 1.4 through 1.6, I have never deep discharged and have never seen a hint of that realignment. It certainly is up to the individual what they want to do, but personally I don't buy into that scenario because it just isn't happening in my experience.
 
You can fly without the app and the Phantom will know how much power is left and go into RTH and auto landing. So it's tracked by the battery, not the app.

To clarify I meant the software on the Phantom itself, the aircraft, not the app. I do not know for sure, but I think we could agree it is either tracked by the battery or by the aircraft. The reason I think that it is tracked by the aircraft instead of the battery is because of the data present in the .dat file (the file that is only saved on the aircraft that records about 600 points per second). Things that are tracked are all the voltages, the current, the average current, the max current, the remaining capacity in milliamp-hours, the battery temperature, etc... If I were DJI I would want to limit the number of sensors in the overall battery/aircraft system (lower cost, lower weight). So, I would not have redundant current sensors which leads me to think the current sensor(s) is on the aircraft and not the battery, it would save a lot of cost that way. If you look at how the battery connects you could block the gold contacts on the bottom so only the 2 main contracts plug in, this would probably answer the question although I expect you would get a battery error...

Either way, tracking the remaining capacity is most accurate from full charge down rather than from a dead battery up while charging....so....I will continue my practice and I expect my battery will last longer than someone that takes it below say 10%....we can compare our results to see which works better. I consider my batteries to be fairly new, they both still show 100% life with about 20 charges on each....
 
Hmmm, wouldn't it be cool if DJI had a rep on here to tell us exactly what controls what, instead of folks (knowledgeable or not) guessing what's going on?!
No insult intended, just expressing my thought/idea.
 
To clarify I meant the software on the Phantom itself, the aircraft, not the app. I do not know for sure, but I think we could agree it is either tracked by the battery or by the aircraft. The reason I think that it is tracked by the aircraft instead of the battery is because of the data present in the .dat file (the file that is only saved on the aircraft that records about 600 points per second). Things that are tracked are all the voltages, the current, the average current, the max current, the remaining capacity in milliamp-hours, the battery temperature, etc... If I were DJI I would want to limit the number of sensors in the overall battery/aircraft system (lower cost, lower weight). So, I would not have redundant current sensors which leads me to think the current sensor(s) is on the aircraft and not the battery, it would save a lot of cost that way. If you look at how the battery connects you could block the gold contacts on the bottom so only the 2 main contracts plug in, this would probably answer the question although I expect you would get a battery error...

Either way, tracking the remaining capacity is most accurate from full charge down rather than from a dead battery up while charging....so....I will continue my practice and I expect my battery will last longer than someone that takes it below say 10%....we can compare our results to see which works better. I consider my batteries to be fairly new, they both still show 100% life with about 20 charges on each....

I blocked the two lower pins and got battery error. It would not let me start the engines. There was no battery data available at all, I expected maybe total voltage would show without those pins. My next question is where is the current sensor...anyone find a good tear down of the phantom 3 battery?
 
I found a good teardown of an Inspire battery

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The red wire is directly connected to the connector for the craft and the black wires connect near each other on the board, looks like a bus to me. I don't see anyway to measure current...so perhaps voltages are measured by the battery and current on the aircraft. The aircraft software might combine both to track battery percentage. Although I guess the aircraft could share current info with the battery...
 
What do you mean by "state of charge?" Charge percentage? The battery can report to you a range of the charge percentage by the number of lights it shows on a button check. Also, I have a couple Venom aftermarket batteries, and they show the charge percentage in digits on a screen right there on the face of the battery. Finally, one of the reasons we do a deep discharge is to calibrate the reading so that the battery doesn't report bad information (i.e. inaccurate charge percentage) - as tcope explained above.


FYI

the P3 uses a completely different software and FW than the P2 vision.

the batteries are NOT the same and have completely different firmware onboard vs the p2 batteries.

until I got my first p3 after my p2's I had no idea how much more info is available to the GO app vs VISION app.

night and day.

the 4 lights are very general and UNRELIABLE except as a rough guide.
The GO app shows EXACT volt per cell in real time
 
I blocked the two lower pins and got battery error. It would not let me start the engines. There was no battery data available at all, I expected maybe total voltage would show without those pins. My next question is where is the current sensor...anyone find a good tear down of the phantom 3 battery?

Below picture of datconverted log of a single battery. Flight that lasted 14minutes. Average amp draw 11.39 from motor start to motor stop.
And a dual battery mod.2x 2400 mAh. Flight lasted 29minutes. Average amp draw 8.64 from motor start to motor stop as logged in the Dat and converted with Datconverter.
The two additional batteries are connected at the outputs of the stock battery's + and - terminals (so in the stock battery). Clearly this shows that current is being measured before the connection of the 2 additional batteries (as in reality amp draw should be higher with a dual battery mod) . So current sensor must be in the stock battery and not in the aircraft.
Untitled.jpg
 
Below picture of datconverted log of a single battery. Flight that lasted 14minutes. Average amp draw 11.39 from motor start to motor stop.
And a dual battery mod.2x 2400 mAh. Flight lasted 29minutes. Average amp draw 8.64 from motor start to motor stop as logged in the Dat and converted with Datconverter.
The two additional batteries are connected at the outputs of the stock battery's + and - terminals (so in the stock battery). Clearly this shows that current is being measured before the connection of the 2 additional batteries (as in reality amp draw should be higher with a dual battery mod) . So current sensor must be in the stock battery and not in the aircraft.
View attachment 42989

You mean higher because of the added weight? It should not be that much higher going to the motors. If I understand you correctly the two additional batteries are in parallel with the stock battery, so unless the current sensor is in between the stock cells it should be the same. If was in between the stock cells it should be about half...also the flight profile looks pretty different....but you could be right. I noticed in the .txt files I have been studying that current is available in the center. and not smart battery heading....which leads me to think it is not from the smart battery....but again could be wrong...

Can you send me links to the .dat files? I am curious how the remaining capacity looks for the dual battery mode. I expect it to follow current integration with period corrections because the voltage doesn't drop....
 
it would possibly be helpful if a message flashed up prior to flying a partially discharged battery warning you of the need to warm the battery to 30degrees or above prior to flight to avoid critical battery warnings
 
What would be convenient is a lamp right there on the face of the battery to tell us the battery temp (e.g. blue = below 20 C, green = 20C - 29C, orange = 30C - 35 C, red = over 35 C). Another convenience would be a dedicated battery warmer designed to achieve the ideal temp, but which would shut off at some point once that temp is reached.
 
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Actually, it could well have been battery temperature. Watch this battery test video.
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Where can I find that test rig?
 
Seems clear you're playing Russian Roulette if you fly on a battery that hasn't been charged to 100% the same day
 
This evening while doing my monthly battery testing I was able to "accidentally" recreate the falling out of the sky "dead" issue. I flew several different locations today and came home with some partially discharged batteries. The last day of the month I log all of my batteries and deep discharge any that are around the 20 cycle mark (20, 40, 60, 80 etc).

I had a battery that was at 47% and I wanted to run it down to less than 10% to initiate the Recalibration function of the Smart Battery. I was watching the actual battery statistics while hovering just above eye level. I wanted to see just how much difference putting a heavy load on this battery would do so I (don't repeat this at home it's not safe) took hold of the landing skid and applied more throttle. The motors revved hard but the battery indicator was barely showing red on one cell so I increased the throttle more. Tx immediately indicated "Critically Low Voltage" (still showing 45% capacity but voltage was red on every cell). Within about 2 seconds the aircraft completely powered down and had I not been holding the landing skid it would have tumbled to the ground.

So if you are trying to get a few more minutes by flying with a partially charge pack realize you could very easily cause a complete power-down.

Air temp was roughly 54degs so it was not a cold battery issue at all.

Good luck and fly safe.
That confirms my thoughts of Get Extra Batteries so you can fly longer. I want 5 all together. 1 in the quad, 1 on the charger, and 3 cooling down ready to be charged .... or charged ready to go. Also DANGER WILL ROGERS > Stay away from the cheap batteries out there claiming longer flight times and 1/2 the price. They're not as good as the DJI Batteries.
 
I wonder if the cheaper batteries could actually be made to be smarter than the the "Smart" batteries that can turn off during flight? Riddle me that riddler.

Dumbest thing I have ever heard. Battery turns off because it could be damaged.. Phantom drops from the sky killing the copter and the battery anyway... Real smart.


Sent from my iPad using PhantomPilots mobile app
 
How many copters with cheap batteries have fallen from the sky.


Sent from my iPad using PhantomPilots mobile app
 
Hmmm, wouldn't it be cool if DJI had a rep on here to tell us exactly what controls what, instead of folks (knowledgeable or not) guessing what's going on?!
No insult intended, just expressing my thought/idea.
They have them on the DJI forum - they are friendly and helpful (for warranty stuff) but they do not seem to have much in the way of in depth technical knowledge. Would be nice.
 
What would be convenient is a lamp right there on the face of the battery to tell us the battery temp (e.g. blue = below 20 C, green = 20C - 29C, orange = 30C - 35 C, red = over 35 C). Another convenience would be a dedicated battery warmer designed to achieve the ideal temp, but which would shut off at some point once that temp is reached.
Jacket pockets work for warmers. You can get a non contact infrared thermometer for a few bucks and point it at the battery. Actually might do that (I have several of them) to see what the temps are at the start. This morning I started a flight at 2C and after 20 minutes or so, pulled the battery and it was 25C. Healthy Drones also displays battery temps after the fact.
 
Don't really understand all the pro's/cons ect., voltages, temps You are suppose to take off with a fully charged battery. Not 80, not 75 ect,. I am glad you did this experiment. Maybe this will reinject common sense when a mfg tells you TAKE OFF AT 100% BATTERY ALWAYS, THEN DO JUST THAT. I just don't understand all the discussion, after BigA proved to all that this might or probably is and issue for some of the crashes.
 
Don't really understand all the pro's/cons ect., voltages, temps You are suppose to take off with a fully charged battery. Not 80, not 75 ect,. I am glad you did this experiment. Maybe this will reinject common sense when a mfg tells you TAKE OFF AT 100% BATTERY ALWAYS, THEN DO JUST THAT. I just don't understand all the discussion, after BigA proved to all that this might or probably is and issue for some of the crashes.
Actually, The Fine Manual stays start at something above 50%. It's not always practical to start with a full battery and if DJI says 50%, they ought to engineer it so it can safely fly at 50%. I always try to start with a full charge, I like the ability to stay up as long as possible and the safety it presumably offers. But it's pretty clear that DJI needs to get a better handle on battery voltages and how the P3 reacts to them.
 

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