Meta4...Doesn't the fact that the battery at take off in the first flight was only 49% and at 53% on the second flight take off play into this?
P4 started to fly off on its own
- Thread starter cinclodes
- Start date
The battery wasn't charged (or even removed) between the flights. It was an unusually warm day for Virginia in December. There were no metal objects nearby. I had launched from the same spot several times previously. I'm not aware of anything that might have caused the problem or why it didn't happen again when I tried another flight a few days later.
It is highly recommended to always have a fully charged battery at the beginning of every flight.
Why does it matter? Suppose you are out in the field in a remote area. You want to do several short flights. You only have so many batteries. Is there any reason to forgo some of your objectives rather than do some of the flights with partially charged batteries? I'm not aware of any reason not to fly with a partially charged battery as long as it has sufficient charge to do the flight and get back on the ground with plenty to spare.
Well, it’s up to you. But, I would suggest that you do a little research on this forum about the hazards of Not starting your flight with a fully charged battery. It’s your drone, you may have ‘plenty to spare’ but then maybe you don’t. Just saying.
If there are any such hazards, I would like to know. For starters, could you please name one of them here?
Per Captain Labroides:
If you are saying you flew the battery down to 60% and flew again a few days later without recharging the battery, then your assumption that it had ample charge is incorrect.
The % indicator gives you a false reading when you start with a partially discharged battery.
What matters to the Phantom is actual voltage the battery can provide and when that gets close to 3.3V the Phantom will Autoland to prevent damaging the battery and/or crashing.
To see what voltage you were getting from your battery go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
and Per Tmygun:
The only REAL time the battery % is accurate is usually after charging the battery to 100%. If you use the fully charged battery, come in land at 60% and go back out 10-15 minutes etc later.....the percentages should be relatively accurate.....BUT if you run your battery percentage down to 60% and then don't use it again for a few days, the battery may still show close to 60% capacity but the voltage may be a lot lower and more critical. Voltage IS, if not MORE important, as important as capacity......I have two examples that might help.
5 weeks ago had a P4 battery that I had charged up on the P4 charger to storage capacity (51%), at least 4 weeks earlier, probably longer......still showed to two solid green and one blinking green when pressed indicating a charge of at least 51%. Put the battery on the charger to do a full charge and just after it started charging the status lights rolled back to only the first light on the battery blinking green.........meaning less then 10% of the battery remained . I realized the battery WAS at 51% until the charger put a load on the battery, checking the status as the smart charger does, and BOOM...the voltage dropped, and in reality it was really less then 10%. The battery charged normally......but it doesn't take much to realize what would have happened had I put that in my P4 and got to 100 feet high.........BOOM.
2 weeks ago I charged a P3 that had drained to one light over a period of time.....I then charged the battery to @ 60% just to check out a compass calibration I did......started the P3 went up to 25 feet slowly......happened to have the battery screen up, and saw the battery cells drop into the red almost immediately....@ 3.6 Volts. I realized I had made a mistake thinking that if I charged the battery up to 60%......it was really 60%. I also did some digging before I read this thread and ascertained that LiPo batteries do not charge uniformly over the whole charging cycle.......the capacity goes up faster then the voltage. If you watch a battery charging carfully it seems to get up to 75%+ pretty fast and then seems to take a very long time to finish up the full charge.
You might get away with using a depleted, days old battery.......under the right circumstances......but is it really worth it!
The only REAL time the battery % is accurate is usually after charging the battery to 100%. If you use the fully charged battery, come in land at 60% and go back out 10-15 minutes etc later.....the percentages should be relatively accurate.....BUT if you run your battery percentage down to 60% and then don't use it again for a few days, the battery may still show close to 60% capacity but the voltage may be a lot lower and more critical. Voltage IS, if not MORE important, as important as capacity......I have two examples that might help.
5 weeks ago had a P4 battery that I had charged up on the P4 charger to storage capacity (51%), at least 4 weeks earlier, probably longer......still showed to two solid green and one blinking green when pressed indicating a charge of at least 51%. Put the battery on the charger to do a full charge and just after it started charging the status lights rolled back to only the first light on the battery blinking green.........meaning less then 10% of the battery remained . I realized the battery WAS at 51% until the charger put a load on the battery, checking the status as the smart charger does, and BOOM...the voltage dropped, and in reality it was really less then 10%. The battery charged normally......but it doesn't take much to realize what would have happened had I put that in my P4 and got to 100 feet high.........BOOM.
2 weeks ago I charged a P3 that had drained to one light over a period of time.....I then charged the battery to @ 60% just to check out a compass calibration I did......started the P3 went up to 25 feet slowly......happened to have the battery screen up, and saw the battery cells drop into the red almost immediately....@ 3.6 Volts. I realized I had made a mistake thinking that if I charged the battery up to 60%......it was really 60%. I also did some digging before I read this thread and ascertained that LiPo batteries do not charge uniformly over the whole charging cycle.......the capacity goes up faster then the voltage. If you watch a battery charging carfully it seems to get up to 75%+ pretty fast and then seems to take a very long time to finish up the full charge.
You might get away with using a depleted, days old battery.......under the right circumstances......but is it really worth it!
Meta4
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Battery level at start won't cause irregular flight.
But it can lead to fall-from-the sky incidents.
If you fly, land and fly again, that's no problem.
If you fly today, land and fly a week or more later, the battery discharges and gives a false % indication.
In bad cases it can lead to incidents where the battery voltage crashes (and so does the drone).
There have been plenty of cases of this.
Like this one just this week:
compass error over water
Xrider - was the fight just over 5 minutes (am I reading the data correctly). This is the compass plot, can't see anything significant there?? Bit of a glitch about 1½ BEFORE lift off. Maybe someone more experienced can read more into it. You're right the only compass problem occurred at...
phantompilots.com
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