Professional Partial Charge

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I seem to recall some discussion on this quite awhile back, but couldn't find anything. I went out today with my P3P. Two of my batteries were showing 3 of 4 LEDs and were in the mid 60% range; however, I barely got the 'copter off the ground when I got a critical low battery warning and was told the 'copter was about to land itself. This happened on both batteries. I'm going to go out in the yard and try again, hovering only a few feet off the grass, to see what happens, but does this sound "normal?"

I remember someone suggesting that you don't use a partially depleted battery. Just charge it up to full before using it, regardless of the existing charge.

Thanks in advance for any input.

ms
 

ianzone

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Sounds like its predicting flight time ,,no not normal,,not recommended to fly semi charged but it should still be ok till critical warning settings are reached before any prompts come up,check all those smart rth settings are off
 
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I did set the warning to come on at 40%. I believe it was originally 30%, and I do recall changing that. The difference here was that I was barely off the ground and it landed itself automatically and was still showing somewhere in the mid 60% area. Normally, it's not giving me any warnings at this level.

I tried it a few times, using both batteries. I was able to coax it nearer where I was standing as it was auto-landing, but it still landed itself. The third time, I just let it alone and it landed straight down where it was (not near home) and shut the props off.

I charged both batteries and am going to try them again today and see what happens.
 
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I did set the warning to come on at 40%. I believe it was originally 30%, and I do recall changing that. The difference here was that I was barely off the ground and it landed itself automatically and was still showing somewhere in the mid 60% area. Normally, it's not giving me any warnings at this level.

I tried it a few times, using both batteries. I was able to coax it nearer where I was standing as it was auto-landing, but it still landed itself. The third time, I just let it alone and it landed straight down where it was (not near home) and shut the props off.

I charged both batteries and am going to try them again today and see what happens.
I would set the warning to about 20%..... that is still a reasonable time for the Phantom to get home. Charge your batteries to 100% before flying to prevent problems
 
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If you fly further than 100m then 20% might be too low. If the batt. not entirely new the voltage can drop below the critical value even at more than 20% and if you have luck an instant landing will turn on. In worse the batt. might shut down.
 

Oso

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I seem to recall some discussion on this quite awhile back, but couldn't find anything. I went out today with my P3P. Two of my batteries were showing 3 of 4 LEDs and were in the mid 60% range; however, I barely got the 'copter off the ground when I got a critical low battery warning and was told the 'copter was about to land itself. This happened on both batteries. I'm going to go out in the yard and try again, hovering only a few feet off the grass, to see what happens, but does this sound "normal?"

I remember someone suggesting that you don't use a partially depleted battery. Just charge it up to full before using it, regardless of the existing charge.

Thanks in advance for any input.

ms
It’s not only “quite a while back” that we warned people about fully charging batteries. It seems we’ve done it relatively often over the last 5-6 years.

In a nutshell, unless you’ve started with a fully charged battery, the % indicator is not a reliable way to judge the battery’s ability for safe flight. Instead, the voltage remaining is better to use as a more accurate measure.
 
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Well, I charged 'em all up completely and haven't had any issues, so basically the replies I've received basically reinforced what I already suspected.

Thanks for all the quick answers.
 

Meta4

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I remember someone suggesting that you don't use a partially depleted battery. Just charge it up to full before using it, regardless of the existing charge.
Someone was correct.
Launching with a batter that's been sitting around discharging is just asking for trouble.
The % indicator is only useful if you launch with a freshly charged battery.
If you looked at your recorded data, you'd see that the voltage was much lower than it should have been and quickly sank.
 
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Yup, this pretty much proved it to me. I saw three LEDs and a flashing 4th one, so I figured that must be good for several minutes, but nope.

Charged 'em up, and all was fine.

I guess my brain is still back in the NiCAD days when "they" said you should discharge them completely before recharging.
 

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