80 to 90% battery level takeoff is triggering outrage

[Chief Joe]

I don't think DJI meant for this to occur. The critical low battery feature is supposed to auto land the Phantom at its current location before the battery shuts off. It seems they just didn't foresee how some Phantom pilots were going to attempt to fly with a low battery.

I agree. This seems to be an unintended consequence of normal disparity between separate systems (the P3, the Go app, and the Smart Battery) and mathematical averaging vs data display. Add to that a current spike from other than expected use (max vertical velocity, near max speed or some other strain) and the battery may be shutting down to protect itself faster than it can be detected by the P3 or can notify the P3 and Go app. I have seen this behavior before on battery run systems using programming. It was never a "Bug" or a programming error, but always a result of the interactions of the separate systems and the "self preservation" mode. If the shutoff is from a spike caused by using the system with low voltage in the battery then the "Failsafe" shutdown programming will need to be better integrated with the onboard system and the Go app. So far like you I have not seen any proof of what or how the "shutdown" is occurring.

 

[Air Ontario]

I treat the P3P similar to the Cessna. That includes fuel top off and a run up/warm up, check voltage, etc. prior to takeoff.

I charge the batteries fully, watch the battery voltage and temp, start and run up for 10-30 seconds watching the battery temps and voltage, the lift off and go.

No issues so far in -8 to -10C, with slow flight or warp drive. However in fairness, I am still breaking in batteries so I land with no less than 60% charge indicated.

 

[John Locke]

View attachment 40859
I am one of those people as well. After 190 successful flights on my P3P, one of my batteries displayed 85% remaining, with a lowest cell voltage of 4.05V before launch. I flew it straight up to 240 feet, and the P3P dropped like a rock and crashed onto concrete 15 seconds into the flight, due to an in flight battery shut off, with a "Low Voltage Protection" displayed as Record 01 in the Battery History afterwards. Aircraft Firmware version 1.4.1. After the the crash, the battery still read 82% remaining with a lowest cell voltage of 4.07V and 100% battery life remaining. Battery had not been topped off before flying, and had been left idle for 2 weeks with a 10 day time to discharge, but I only planned a 2 minute test flight, so with 87% and 4 green lights, I figured I was fine. Wrong! Intro screen on newest P3P says to fly with minimum 50% battery and App displayed 87%. Analysis of the iPad Air2 flight log .txt file reveals that the takeoff battery temperature was 70° F and confirms the same battery percentage readouts of the DJI GO app. However, the individual battery cell readings are shown as significantly less, and Cell 4 reached 3.02V just before the shutoff. View attachment 40851

My crash reveals that these crashes can even happen at 70° F (20° C is 68° F), and with an app readout of 87% remaining battery, and with firmware prior to 1.5. ......

I can't speak to 1.6 being a panacea for these problems, but the in flight battery shut offs are not exclusively limited to 1.5,

This is interesting. DJI told me at CES that they had no reports of battery shutdown on 1.4 and before, only 1.5. You're the only one I remember too with this issue on 1.4. Hmm

 

[GadgetGuy]

This is interesting. DJI told me at CES that they had no reports of battery shutdown on 1.4 and before, only 1.5. You're the only one I remember too with this issue on 1.4. Hmm

Now they do. That's why I wanted to bring it to everyone's attention. The issue likely been there all along, but does require a perfect storm of circumstances to be triggered on 1.4.1. Perhaps almost as rare as an inadvertent CSC in flight. However, it is still possible, even without the exacerbation from 1.5. Given that I have always rotated my four batteries, and rarely ever allowed any of them to get into a discharge state by flying almost daily, and always topping off the next battery in sequence, after fully charging the just flown battery, I have never previously flown on a battery stored over 10 days without first topping off, in over 200 flights. I usually use them without topping off for formatting cards and playing around with app settings, and installing firmware updates and IMU calibrations, where the battery load is minimal. So, the battery shutoff in flight has ocurred before 1.5, and storage past the 10 day battery discharge time is a trigger, as is 70° or lower battery temperature, along with prolonged full load at launch, if topping off has not been done before flight. DJI also definitely needs to change the new pilot intro screen, shown above, which clearly and naively states that more than 50% battery is enough to fly safely! It's only true, if the battery was topped off, before the first flight of the day!

 

[skyeboysteve]

I treat the P3P similar to the Cessna. That includes fuel top off and a run up/warm up, check voltage, etc. prior to takeoff.

Not always a good idea to top off your Cessna if taking off from high density altitude airport. Unlike your P3 you can't peer visually into your battery to see energy level. One thing about your Cessna fuel gauges--never trust them unless the needle points at "E".

 

[John Locke]

Now they do. That's why I wanted to bring it to everyone's attention. The issue likely been there all along, but does require a perfect storm of circumstances to be triggered on 1.4.1. Perhaps almost as rare as an inadvertent CSC in flight. However, it is still possible, even without the exacerbation from 1.5. Given that I have always rotated my four batteries, and rarely ever allowed any of them to get into a discharge state by flying almost daily, and always topping off the next battery in sequence, after fully charging the just flown battery, I have never previously flown on a battery stored over 10 days without first topping off, in over 200 flights. I usually use them without topping off for formatting cards and playing around with app settings, and installing firmware updates and IMU calibrations, where the battery load is minimal. So, the battery shutoff in flight has ocurred before 1.5, and storage past the 10 day battery discharge time is a trigger, as is 70° or lower battery temperature, along with prolonged full load at launch, if topping off has not been done before flight. DJI also definitely needs to change the new pilot intro screen, shown above, which clearly and naively states that more than 50% battery is enough to fly safely! It's only true, if the battery was topped off, before the first flight of the day!

Can you elaborate on the circumstances that triggered your 1.4 firmware to shut down battery power? You've stated:
1. The battery had sat over 10 days, implying it should have been in the discharge mode for a period of days.
2. Battery was somewhere below 70F (somewhere near 70F) when you were flying. (Why do you think that's an issue? That's pretty warm, well within reason).

Questions:
A. Do you recall the battery level in percent right after you took off?
B. Did the battery shut down occur when you applied full throttle for a prolonged period of time (as implied)?
C. About how many minutes of flight occurred before the battery power was shut down?
D. Do you recall if the battery sat over 12 days? If that's the case, it should have completed the discharge cycle, down to about 60-70%.

 

[BVC]

You wrote: "I think there is more old timers on here bloating the subject more so because it's something to talk about vs reality." Being what you would refer to as an 'old timer' I take exception to what you wrote. You're a pompous horse's patoot and don't say that what you meant by "old timer" was referring to guys who have posted here in the past... we know what you meant, junior. Forums exist NOT to discuss how wonderful things are, forums have ALWAY existed (since dinosaurs flew when I was a young man) to offer solutions to perceived or real (re: reality) problems and to discuss how to solve them... not to toot one's horn and say how much sunshine, unicorns, and skittle rainbows can be blown up your *** when flying these expensive machines. Get over yourself. If you don't like reading these forums, leave and never come back again. I in particular appreciate people voicing their problems and other people offering solutions in forums like this. Dealing with quad manufacturers and trying to get them to reveal the Great Oz behind that curtain, and revealing why their quads inexplicably fail is like pulling teeth out of a hen's beak (re: impossible) so get over yourself. I now step off my soapbox.

****. Soap opera over here.. not sure what exactly what you were trying to explain other than drooling out nonsense everyone already knows about?

Stop your complaining and man up. Sheesh

 

[GadgetGuy]

Can you elaborate on the circumstances that triggered your 1.4 firmware to shut down battery power? You've stated:
1. The battery had sat over 10 days, implying it should have been in the discharge mode for a period of days.
2. Battery was somewhere below 70F (somewhere near 70F) when you were flying. (Why do you think that's an issue? That's pretty warm, well within reason).

Questions:
A. Do you recall the battery level in percent right after you took off?
B. Did the battery shut down occur when you applied full throttle for a prolonged period of time (as implied)?
C. About how many minutes of flight occurred before the battery power was shut down?
D. Do you recall if the battery sat over 12 days? If that's the case, it should have completed the discharge cycle, down to about 60-70%.

Happy to fill in the details. I appreciate your interest.
A. 87% upon launch, and it still read 85% after the crash, as the battery survived, and it's History Record 01 read, in red, "Critical battery protection" instead of "Normal", as the other History Records 02-20 read in black.
B. Yes, ascent straight up to 240 feet, under full throttle
C. Shutdown and crash just 16 seconds into the flight, and P3P slammed straight down into the concrete steps just 15 feet away from me, over the edge of the deck I had launched from. My only clue while looking at the iPad was the red No Signal and red transmitter LED, which caused me to look up to see the last 20 feet of the fall. Video recording ended at 22 seconds, and was recovered in a new P3P, and shows nothing unusual except the ascent to 240 feet, where it ends at the time the battery shut down.
D. Battery definitely sat unused for well over 12 days, which is why I was surprised that it still read 4 green LED's, and that it still read 87% remaining in the app with 4.07V on the lowest cell, obviously in error! However, I only planned a 2 minute test flight, so I naively assumed I was fine. Besides, DJI says fly with anything over 50%+ battery in their new intro screen!
E. As to the 70°F, the 20°C cautionary threshold is 68°F, which means the starting battery temperature was within a fudge factor of the 20°C. I don't know where the 20°C or less came from, but 2°F difference is certainly close enough that the starting temperature was undoubtedly a likely contributory factor.
I also have supporting screen shots of all the above, should you wish to see them. Let me know if there is anything else I can supply to help.

 

[Ken Hanks]

Battery Charging

 

[John Locke]

Happy to fill in the details. I appreciate your interest.
A. 87% upon launch, and it still read 85% after the crash, as the battery survived, and it's History Record 01 read, in red, "Critical battery protection" instead of "Normal", as the other History Records 02-20 read in black.
B. Yes, ascent straight up to 240 feet, under full throttle
C. Shutdown and crash just 16 seconds into the flight, and P3P slammed straight down into the concrete steps just 15 feet away from me, over the edge of the deck I had launched from. My only clue while looking at the iPad was the red No Signal and red transmitter LED, which caused me to look up to see the last 20 feet of the fall. Video recording ended at 22 seconds, and was recovered in a new P3P, and shows nothing unusual except the ascent to 240 feet, where it ends at the time the battery shut down.
D. Battery definitely sat unused for well over 12 days, which is why I was surprised that it still read 4 green LED's, and that it still read 87% remaining in the app with 4.07V on the lowest cell, obviously in error! However, I only planned a 2 minute test flight, so I naively assumed I was fine. Besides, DJI says fly with anything over 50%+ battery in their new intro screen!
E. As to the 70°F, the 20°C cautionary threshold is 68°F, which means the starting battery temperature was within a fudge factor of the 20°C. I don't know where the 20°C or less came from, but 2°F difference is certainly close enough that the starting temperature was undoubtedly a likely contributory factor.
I also have supporting screen shots of all the above, should you wish to see them. Let me know if there is anything else I can supply to help.

That's very interesting. Your 1.4 firmware issue is almost identical to the 1.5 firmware incidents that have been reported, less than full charge, discharge mode, and high battery stress (full throttle). What did DJI tell you when they saw your flight records? Did they help you financially in any way?

 

[GadgetGuy]

That's very interesting. Your 1.4 firmware issue is almost identical to the 1.5 firmware incidents that have been reported, less than full charge, discharge mode, and high battery stress (full throttle). What did DJI tell you when they saw your flight records? Did they help you financially in any way?

I agree. Clearly due to the combination of the exact same factors. I'm expecting DJI to repair or replace under warranty, but that hasn't been settled yet. Crash only occurred on New Year's Day, just as I was preparing for a multi-hour series of destination flights and charging up all my other batteries, and running a test flight while waiting. I already have an RMA# but intend upon getting a better commitment with a support manager first, from my irrefutable documentation, before sending the bird in, which won't do anything other than confirm what the rest of the electronic files have already established.

 

[Sim597]

g`day all ,,,, sorry to jump in but does this happen to just the P3 as i have a P2v+and have never had any dramas at all . have logged more than 450 flights some with very low take off voltage of 40%
I am thinking of upgrading to the P3 but not real happy about all the falling out the sky type posts ?

ps after 450 flights im still on my first set of props ,,, never crashed

am i doing something wrong ?

Not besides the constant bragging! Just kidding, wow you sure give guys like me with 1.5hrs on thier p3a or p3s or "p3p", hope! That's pretty impressive and I hope your still having fun with it.
I'm still so new I scream to my wife to bring out her iPhone to video me because I'm so nervous to have a bird 300+ ft up, rainy here for a few days in N Houston area, but soon as it clears I'm going for 335 meters (1000' plus) but just so nervous! It is part of the fun and guess.

 

[bruinboy]

Just checking in to see if this issue is still affecting people. I have firmware v1.9.6 and I'm wondering if this has been fixed since the nightmare that was v1.5.

 

[robinb]

I think that was isolated to 1.5

 

[msinger]

I think that was isolated to 1.5

Right. This issue has not resurfaced since then.

 

[Dirty Bird]

There are many threads here on Phantoms suffering battery shutdowns when flown with partially-charged batteries. Explaining this in detail a thousandth time isn't going to help. The short version is a Phantom calculates it battery level based on VOLTAGE. A Li-Po recovers voltage after use when it sits idle. Installing a partially-charged battery thus gives the flight computer a false reading of the battery level because it is based solely on voltage. As soon as you begin using a battery in this partially-charged state, the voltage quickly begins to drop. If it drops to 3 volts, the battery shuts down & your Phantom falls from the sky. It is exacerbated by the battery being cold where it is less capable of sustaining the high-currents required for high-powered flight. If you carefully monitor your cell voltages you CAN fly with a partially-charged pack. Just remember if ANY CELL drops to 3 volts the battery shuts down immediately.

The real question you need to ask yourself is: Are you willing to risk losing your Phantom and possibly injuring someone because you want to fly with a partially-charged battery versus the few minutes it takes to charge the battery to 100% capacity?

This is all useful information. My question is how much of this is hearsay and how much is useful. Monitoring voltage is always a good idea and there is scientific data about low voltage causing total craft failure.

But these other allegations about false high charge readings after discharge - are they credible? Is there actual consensus on this problem and does the most recent upgrade - which I have yet to implement - actually fix this as a known issue? It's hard to separate hearsay from fact sometimes on here.

 

[GadgetGuy]

There are many threads here on Phantoms suffering battery shutdowns when flown with partially-charged batteries. Explaining this in detail a thousandth time isn't going to help. The short version is a Phantom calculates it battery level based on VOLTAGE. A Li-Po recovers voltage after use when it sits idle. Installing a partially-charged battery thus gives the flight computer a false reading of the battery level because it is based solely on voltage. As soon as you begin using a battery in this partially-charged state, the voltage quickly begins to drop. If it drops to 3 volts, the battery shuts down & your Phantom falls from the sky. It is exacerbated by the battery being cold where it is less capable of sustaining the high-currents required for high-powered flight. If you carefully monitor your cell voltages you CAN fly with a partially-charged pack. Just remember if ANY CELL drops to 3 volts the battery shuts down immediately.

The real question you need to ask yourself is: Are you willing to risk losing your Phantom and possibly injuring someone because you want to fly with a partially-charged battery versus the few minutes it takes to charge the battery to 100% capacity?

+1! Great summary and correct on every aspect. Lost my best P3P flying machine to this very issue, after 195 successful flights! Live and learn! Now if the P4 smart battery chip would only allow topping off a P4 battery to 100% like a P3 battery, without first draining it down to 95%! Makes no sense the DJI made it so difficult to begin with a fully charged P4 battery at 100%!

 

[John Locke]

+1! Great summary and correct on every aspect. Lost my best P3P flying machine to this very issue, after 195 successful flights! Live and learn! Now if the P4 smart battery chip would only allow topping off a P4 battery to 100% like a P3 battery, without first draining it down to 95%! Makes no sense the DJI made it so difficult to begin with a fully charged P4 battery at 100%!

Hey GadgetGuy, I never heard if DJI repaired your P3P under warranty. I assume not since you said you "lost my best P3P". Is that a good assumption? What did your flight records show? Did the a single cell voltage ever get down to 3.0V to trigger the shutdown?

 

[GadgetGuy]

Hey GadgetGuy, I never heard if DJI repaired your P3P under warranty. I assume not since you said you "lost my best P3P". Is that a good assumption? What did your flight records show? Did the a single cell voltage ever get down to 3.0V to trigger the shutdown?

DJI replaced my P3P under warranty with a cannibalized P3A with a P3P gimbal and 4K camera attached, and a P3P name plate, and upgraded the firmware to 1.5 over my explicit instructions not to upgrade the firmware, which had been on 1.4.3. So, I lost my best bird, but it was replaced under warranty with a similar enough one not to complain too loudly. The W322 has .69 watts for video instead of .73 watts on the W323. Close enough. Flight records clearly show a voltage drop on one cell to 3.0V just before shutoff in midair from 215 feet. It was in a discharge state, even though the battery remaining percentage reported 87% at takeoff. Top off your P3 batteries to 100% immediately before flight, to properly rebalance all cells, to get a proper % readout. Unfortunately, it is very difficult to do this on a P4 battery.

 

[skipilot1]

I have no problem with flying a 100% charged battery that sat a week. Been doing this for awhile and the battery life on all of mine show 100%. I do monitor the voltage on the main screen though.

IMHO those that set discharge to start at two days and then top them off a day later or so to fly are too conservative. YMMV.

What are normal voltage readings, and what voltage readings should you use when deciding to return or RTH?