Major Battery Voltage Deviation

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My P3P Battery #1 has a major voltage deviation in Cell #1 (0.102v). During today's flight at 35º F, the AC AutoLanded.

Since the AC was still close to the Home Point, I could see the status lights were flashing red.

AirData.com gave me the two attached battery records.

Question: Is this a correctable problem, or, is the battery done for future flights?

Battery #1 100% Life.png
Battery #1 Major Cell Deviation 0.102v.png
 
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You can probably say good bye to that battery, however worth cycling it, do a full discharge/charge and check again.
 
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I get that cell deviation all the time on Air Data, I ignore it, not saying you should though as an autoland is another matter.
You should get much more than 40 charge cycles from a battery, maybe the cold weather also caused some problem.
 
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Try flying the pack from 100% state of charge and see how it goes.

That battery probably has no major issues.

If you read the Airdata explanation of what those minor deviations indicate (I’m not sure why you think you had a major deviation) you should be comfortable.

The autoland was likely due to the battery reporting critical low voltage.
 
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Way way way......early in my early flights....i flew a with a flight battery that was NOT at full charge...it got dark a few nights before and it was at 60% when i landed it......And a few days later i went to fly...and put that flight battery in at 60% charge Thinking Oh it will Be OK !....BOY did a learn a lesson...it went to auto landing during the flight and i was happy that it did not land in a tree or lake....Thanks for "with the Birds" i now force the battery to *100% charge *...and i have never had a issue with a flight battery.

Thank you " With The Birds ".
 
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You can probably say good bye to that battery, however worth cycling it, do a full discharge/charge and check again.
Cheddarman - I'll consider your suggestion; but first I will charge it up then recheck before doing a full discharge.
 
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I get that cell deviation all the time on Air Data, I ignore it, not saying you should though as an autoland is another matter.
You should get much more than 40 charge cycles from a battery, maybe the cold weather also caused some problem.
Jayfdee - I agree that 40 charges isn't much; but the ten in a row Major cell deviations is the only explanation I have for the AutoLand.
 
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Try flying the pack from 100% state of charge and see how it goes.

That battery probably has no major issues.

If you read the Airdata explanation of what those minor deviations indicate (I’m not sure why you think you had a major deviation) you should be comfortable.

The autoland was likely due to the battery reporting critical low voltage.
Your post gives me hope for this battery! I'm charging it to Full now.

The AirData explanation says, "Major deviation is when a cell differs more than 0.07v from the other cells." And,
"An abnormal battery will:
A) Have most of the major deviations in one cell
B) There will be multiple major deviations per minute, and more than 10 total
C) The deviations continue longer than 1 minute"

So, A) applies to this battery; plus, the deviations were consistently > 0.07v.
B) and C) don't quite apply because the P3P landed in less than a minute from Takeoff. And, the snow and pond below the AC made me less than comfortable. The landing gear were skimming the snow before I realized what was happening; then I throttled it up and over to a dry surface.

I agree that the AutoLand was due to a "Critical Battery Warning" since the status lights were rapidly flashing red. My question is why was there a critical battery warning; and if the battery is still useable, what can I do in the future to avoid this problem.

Thanks for your input With The Birds.
 
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Way way way......early in my early flights....i flew a with a flight battery that was NOT at full charge...it got dark a few nights before and it was at 60% when i landed it......And a few days later i went to fly...and put that flight battery in at 60% charge Thinking Oh it will Be OK !....BOY did a learn a lesson...it went to auto landing during the flight and i was happy that it did not land in a tree or lake....Thanks for "with the Birds" i now force the battery to *100% charge *...and i have never had a issue with a flight battery.

Thank you " With The Birds ".
MotorCycle-Man - I should spend more time on these drone sites; you're the second person to tell me today that a battery should always be flown at 100% charge; Mark the Droner was the other person. I will now follow that advice and see how this suspect battery does. Thanks for your input and case example.
 
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Your post gives me hope for this battery! I'm charging it to Full now.

The AirData explanation says, "Major deviation is when a cell differs more than 0.07v from the other cells." And,
"An abnormal battery will:
A) Have most of the major deviations in one cell
B) There will be multiple major deviations per minute, and more than 10 total
C) The deviations continue longer than 1 minute"

So, A) applies to this battery; plus, the deviations were consistently > 0.07v.
B) and C) don't quite apply because the P3P landed in less than a minute from Takeoff. And, the snow and pond below the AC made me less than comfortable. The landing gear were skimming the snow before I realized what was happening; then I throttled it up and over to a dry surface.

I agree that the AutoLand was due to a "Critical Battery Warning" since the status lights were rapidly flashing red. My question is why was there a critical battery warning; and if the battery is still useable, what can I do in the future to avoid this problem.

Thanks for your input With The Birds.
Airdata might apply 70mv imbalance as being a major deviation. That is very conservative. 100mv is more widely accepted as a significant imbalance.

You have the answer to the autiland. The battery reached critical as set in the GO app.

If that pack had been sitting around for a while and entered auto discharge the imbalance is expected. The same resistors are used to discharge the cells as employed to provide balance bleed down during charging.

The fact you have 100% health reported suggests there is unlikely to be a problem.
 
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Airdata might apply 70mv imbalance as being a major deviation. That is very conservative. 100mv is more widely accepted as a significant imbalance.

You have the answer to the autiland. The battery reached critical as set in the GO app.

If that pack had been sitting around for a while and entered auto discharge the imbalance is expected. The same resistors are used to discharge the cells as employed to provide balance bleed down during charging.

The fact you have 100% health reported suggests there is unlikely to be a problem.
The AirData info lists the battery with 10, 102mv deviations.

The Litchi app was used for this flight.

You're correct, the battery was last used on August 8.

Okay, hope to fly today, weather permitting.

Thanks again for your input.
 
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Okay, flew again today with Battery #1 at 88% charge.
More voltage deviations in cell #1 over several intermittent minutes but lower deviations (0.074v to 0.079v).

The good part was the flight continued for 13 minutes.
No AutoLanding.

Battery #1 Major Cell Deviation 0.074v.png
Battery #1 98% Life.png
 
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Why 88% at launch? Didn’t have time for a full charge?

Yuur wasting your time to the extent your intent might.be to get a true indication if the battery health.

Let it go through a full charge cycle and see where things go then.
 
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Why 88% at launch? Didn’t have time for a full charge?

Yuur wasting your time to the extent your intent might.be to get a true indication if the battery health.

Let it go through a full charge cycle and see where things go then.
You're right; a full charge would be good for battery health evaluation.
I fully charged it, then went through GO and Litchi checking settings then flew at 88% because of impending weather; it was 34ºF | 1ºC when I flew.

Today is blue skies so I'll give it another try at 100% battery.
Thanks for the input.
 
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Yes, indeed, I did just that and the result was a fully balanced battery in each cell. Here are yesterday's results before and after flight:

View attachment 109511 View attachment 109512
Why you might need to set your critical battery warning above the lowest available threshold is a mystery in itself however it is a big clue as to why the phantom wants to autiland earlier than expected.
 

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