Critical voltage warning.

TheRealNick · Dec 6, 2015

John Locke said:
I don't know where you get your information, but if it's really true that a Phantom can't simply use the voltage readings from the battery to determine the charge level for each cell, as displayed in the controller display, this system is a radically flawed design.

The state of charge of a lithium polymer battery can not be determined by voltage alone. You need a known load, current, and voltage drop. As a result I would not fly with partially charged batteries...

shockwave199 · Dec 6, 2015

My SOP has been to charge the battery and fly that day, preferably within a 12 hour time frame and optimally within an hour or so. If after I charge I know I will not be flying for an extended period of time- 4 hours or more- I do not put the battery in the phantom. I leave it out until I'm ready to go flying. The only time I check a charge status is before I charge- mostly out of curiosity. I do not check it once charged. I also do not leave batteries in the phantom between flights. When I'm done flying for the day and foresee multiple days to be grounded, the battery comes out. So far, so good.

Meta4 · Dec 6, 2015

dottat4 said:
I took four batteries. All set to ten day discharge. All fully charged. I kept checking two for fifteen days straight. Each day both answered with ~100% and four green lights. The other two batteries on day 15 had ~55% percent and two solid one blinking. Two were safe to fly. Two were not. All had been charged at the same time. You can keep your batteries from going into this state simply by pressing the power button on them once a day.

Self discharge is to protect the battery because they deteriorate if stored for long periods with a full charge.
Every time you check the battery, it resets the discharge timer so the two that you checked never discharged and the two that you left alone discharged.
They worked exactly as they are intended to.

dottat4 · Dec 6, 2015

Meta4 said:
Self discharge is to protect the battery because they deteriorate if stored for long periods with a full charge.
Every time you check the battery, it resets the discharge timer so the two that you checked never discharged and the two that you left alone discharged.
They worked exactly as they are intended to.

Agreed. Except one thing.

The controller battery log does in fact show that the batteries have done this. The controller should prevent flight and warn the user not to fly on this battery since the controller is capable of detecting this state.

Sent from my Nexus 6 using Tapatalk

Dirby · Dec 6, 2015

i got the same warning one flight and when i landed i noticed that the battery was not all the way in the battery compartment.

stevemitchell · Dec 7, 2015

Oso said:
Seems like these reports are never ending all of a sudden. I know I may sound like a broken record, but I really think something was introduced about a month ago that is leading to these reports.

Anyone care to examine my Flight log from my crash? | DJI Phantom Forum

Critical battery warning | DJI Phantom Forum

I am beginning to think that there was something introduced. I did a ton of flights in October without any problems whatsoever. I'm a long time DJI user, and know good battery maintenance / care. I hadn't had the time to fly very much since October, and after upgrading 3 days ago, I have had 3 separate voltage warnings on two different batteries. These batteries have been discharged less than 10 times each, and are new as of May of this year.

Two of the three times I received the error when the battery was below 60% charge, but the batteries had been flown at least once before, and no issues.

One time, I was trying to reproduce the issue, and with full forward and vertical speed, I was able to get the voltage to drop below the warning threshold, it turned red in the DJI GO app, and autoland kicked in.

I have flown this particular P3 in this very spot a ton of times, and never had this happen. It almost seems like I'm able to get more speed/performance out of the motors than a release or two ago, and that it's causing things to suck the voltage down too much.

Not sure....Or I could just have some faulty batteries, but it seems too coincidental.

shockwave199 · Dec 7, 2015

Has anyone tried disabling smart RTH to see if that clears the issue? Could it be that calculation caught a bug and is reporting battery voltage in error? Just a thought.