[Solved] Major battery voltage deviation - Opinions pls :-)

Elysion · Mar 8, 2016

Hey guys, I asked this in the DJI forum but wanted some extra opinions, if that's okay

I was checking out my flight logs and noticed major deviations in the voltage of my battery.

Since the bird is pretty new (less than a month) and the battery has only been charged 3 times, I wanted to be extra cautios and ask for opinions.

Drone is clean, no crashes, no battery warnings until now, always had the voltages (top right in the app) in sight and flew carefully, no sudden speed-ups.

The only thing I noticed was that sometimes I had sudden drops in voltages from 3.8/3.9 to the high 3.5V areas (seen on top right corner of the app, changing color from green to yellow), thats when I throttled and prepared to fly back.

HealthyDrones.com - Innovative flight data analysis that matters
HealthyDrones.com - Innovative flight data analysis that matters
HealthyDrones.com - Innovative flight data analysis that matters

Please note that with my second battery, I did not have any major deviations until now, both were handled pretty similarly and charged with the same stock charger until full.

"Healthy Battery" #1

"Healthy Battery" #2

Any help is greatly appreciated, thank you in advance for your support

Best regards from Germany-
Elysion

Edit: Ambient temperature was around 0° Celsius / 32° F.

KyleMaxxUAV · Mar 8, 2016

Flight 1 & 3 perfectly fine. Flight 2 has a few deviations but your battery started at 21c, should have been a little warmer if possible(especially in cold temps) and it was not charged to 100% (started at 97%)

I'm going to say it's probably fine, charge it up fully, warm it up to 25c or so and see if it happens again. But you are probably good

Sent from my iPhone using PhantomPilots mobile app

msinger · Mar 8, 2016

"Major deviation is when a cell differs more than 0.07v from the other cells" is a definition made up by the creator of Healthy Drones. Just because your battery reported one "major deviation", it does not necessarily mean there is any reason for concern. Per some research I've done, others feel deviations less than 0.1V should be ignored. If you upload your logs here instead, you'll be able to see all of the recorded deviations.

KyleMaxxUAV · Mar 8, 2016

Also, it appears you just went straight up to 1600ft ? Going full throttle straight up on a cold battery, that wasn't fully charged, in 0c temps is probably not the best idea. ??

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Elysion · Mar 8, 2016

Thanks so much for the fast replies.

Yeah you're right P3P, will fully charge and test again with a warmer battery.

Thank you for the link msinger, will upload my logs to there as well from now on.

Kind regards-
Elysion

Elysion · Mar 8, 2016

P3P Canada said:
Also, it appears you just went straight up to 1600ft ? Going full throttle straight up on a cold battery, that wasn't fully charged, in 0c temps is probably not the best idea. ??

Sent from my iPhone using PhantomPilots mobile app

Well, I wanted to see the maximum altitude, but I never went up full throttle, always easy on the stick, also always had the voltages under control!

KyleMaxxUAV · Mar 8, 2016

Looks fine to me, I had a faulty battery, it was always out of balance(even sitting on the ground) had 10+ major deviations every flight, did a deep discharge cycle to 10% and then full charge . It also started to get a bit swollen.
It was an actual bad battery !!

Contacted DJI, sent photos, disposed of battery, new one is good to go

Sent from my iPhone using PhantomPilots mobile app

Elysion · Mar 8, 2016

P3P Canada said:
Looks fine to me, I had a faulty battery, it was always out of balance(even sitting on the ground) had 10+ major deviations every flight, did a deep discharge cycle to 10% and then full charge . It also started to get a bit swollen.
It was an actual bad battery !!

Contacted DJI, sent photos, disposed of battery, new one is good to go

Sent from my iPhone using PhantomPilots mobile app

Will upload my files to phantomhelp and take a look there, but from what I can tell now, the deviations seem to be within safe range, I will calibrate them as well now and keep an eye on the voltages with a higher temperature (at least 25°C.)

Thanks again for the help, marked as solved

Elysion · Mar 9, 2016

[UPDATE]

Did a complete discharge until the drone went off, while doing so, I noticed big deviations of cell 1, while e.g. Cell 3 was @ 3.2V, Cell 1 was at 3.0V.

I gave it a 30 minute rest at cool temperatures, now charging it to 100%

Also uploaded files to phantomhelp:
Phantom 3 Log Viewer - PhantomHelp.com

@2m 24.6s and @6m 17.5s you can see deviations of over 0.1V of the reported battery, any opinions?

Thanks-
Elysion

Elysion · Mar 9, 2016

[UPDATE #2]

DJI honored my warranty without even asking for logs! They just told me to send it to them and that I'd get a replacement unit within 10 days!

Better safe than sorry, I am willing to wait the few weeks to have a reliable bird in the air, you can never be sure enough ;-)

Thanks again!
Elysion

Baldo81 · Mar 11, 2016

Hi,

I'm having the same issue after a discharge to 8% (the battery has 27cycles).
DJI suggested today to try another discharge to 8% to see if the major deviations go away.

What do you think?

HealthyDrones.com - Innovative flight data analysis that matters
Phantom 3 Log Viewer - PhantomHelp.com

Elysion · Mar 13, 2016

Baldo81 said:
Hi,

I'm having the same issue after a discharge to 8% (the battery has 27cycles).
DJI suggested today to try another discharge to 8% to see if the major deviations go away.

What do you think?

HealthyDrones.com - Innovative flight data analysis that matters
Phantom 3 Log Viewer - PhantomHelp.com

I discharged the batteries until the aircraft turned off by itself, the internal deep discharge protection prevents it from going below 3.0v, which is absolut minimum.
I then let them cool down to about 20° C. and let them rest for about 30-35 minutes, before I recharged them again.

After I did that, my deviations were gone.

The only important notice I want to give you on this is that you never should discharge the batteries too fast, that is what they are really sensible to, I flew my drones to about 25% and then just let them sit still outside my balcony (I wanted a nice airflow to cool down the drone) until they turned off, then do the procedure as stated above.
Some people do not recommend it, as it can lead to battery swelling or even a complete malfunction of the battery, I actually think that not every phantom flyer is not an engineer and just wants to fly that thing until it comes down on its own, that's why the integrated safety features

In general, I really think that it also depends on various circumstances, such as air temeprature, battery temperature, flight behavior and also firmware version (the last one had some additional safety features for cold environments, dunno if that applies to you).

When did the voltage drops occure? Did you suddenly push the stick down to accelerate or just gently push it? Or did you do sudden movements in general?
Also you are down to 27 cycles as you stated, so you might give my method a try if you feel safe in doing it, it helped me:

HealthyDrones.com - Innovative flight data analysis that matters

https://www.phantomhelp.com/LogView...HYQC3W9X7XGWTI5LL-DJIFlightRecord_2016-03-12_[17-35-52].txt

Hope it helped a little! And always remember, keep a cool head and the drone in the air!

Elysion

Baldo81 · Mar 13, 2016

Elysion said:
I discharged the batteries until the aircraft turned off by itself, the internal deep discharge protection prevents it from going below 3.0v, which is absolut minimum.
I then let them cool down to about 20° C. and let them rest for about 30-35 minutes, before I recharged them again.

After I did that, my deviations were gone.

The only important notice I want to give you on this is that you never should discharge the batteries too fast, that is what they are really sensible to, I flew my drones to about 25% and then just let them sit still outside my balcony (I wanted a nice airflow to cool down the drone) until it turns off, then do the procedure as stated above.
Some people do not recommend it, as it can lead to battery swelling or even a complete malfunction of the battery, I actually think that not every phantom flyer is not an engineer and just wants to fly that thing until it comes down on its own, that's why the integrated safety features

In general, I really think that it also depends on various circumstances, such as air temeprature, battery temperature, flight behavior and also firmware version (the last one had some additional safety features for cold environments, dunno if that applies to you).

When did the voltage drops occure? Did you suddenly push the stick down to accelerate or just gently push it? Or did you do sudden movements in general?
Also you are down to 27 cycles as you stated, so you might give my method a try if you feel safe in doing it, it helped me:

HealthyDrones.com - Innovative flight data analysis that matters

https://www.phantomhelp.com/LogView...HYQC3W9X7XGWTI5LL-DJIFlightRecord_2016-03-12_[17-35-52].txt

Hope it helped a little! And always remember, keep a cool head and the drone in the air!

Elysion

Thanks for your help!
I completely agree with you. Both we're using the same method to bring her below 8%
I usually flight gently as as are 5 years that I'm used to fly quads with no-intelligent batteries

I did another discharge cycle and seems better, but I'll see the logs later today as soon as I can upload them.

The deviations I got aren't that big but I prefer to flight safely and trust my batteries

Elysion · Mar 13, 2016

Baldo81 said:
Thanks for your help!
I completely agree with you. Both we're using the same method to bring her below 8%
I usually flight gently as as are 5 years that I'm used to fly quads with no-intelligent batteries
I did another discharge cycle and seems better, but I'll see the logs later today as soon as I can upload them.

The deviations I got aren't that big but I prefer to flight safely and trust my batteries

That's good to hear, keep me updated!
And completely agree with the safety, better safe than sorry

Cheers