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battery reporting bug?
214 8 10-17 07:28
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HereForTheBeer
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i have ben noticing for a little while now i would say last few weeks.   that my my battery seems to charge up to 96% ill charge up and a few hours later when i go to fly and boot the drone i notice both in app and on controller that its 96% indicated i havent paid attention to voltages of 99-100% full battery to know if its spot on for such voltags but still.   i checked and my app set to 5 days before discharging and i moved it to 7 days and same things even at 10 days does it too...   

has anyone else seen this issue and what are your thoughts?  i dont think its a reserve thats being tucked away given if i pull battery and fly it right away i start out with 99-100%  seems only if i let it sit for a few hours will it drop to 96% on startup.  i also left the battery fully charged for a day and still at 96% at start up meaning not bleeding away power from internal hardware defect shorting out and slowly draining power.


additional info: battery has under 50 cycles, was made 06-19, no bloating but there is a tiny bit of a sweet smell i sometimes get fromt he connector area if i pushing the drone hard and getting battery warm but just means tiny bit of offgassing happening which is normal as long as not a constant sweet smell. i have tried calibrating the battery 3x now by fully discharging it slowly turning the drone on and leting it chill on the ground for a good while until turns of then charging the battery but seems the issue remains.   
10-17 07:28
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rwynant V1
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Once the battery starts gassing,  the internal resistance goes up and the MAH storage capacity goes down.  With the 96% reading......that's after the "surface charge" has worn off.

Watch this battery every time you fly it.  at 50% check your cell voltages.....each should be better than 3.75v/cell........when you get to 40%,  if your cells are reading below 3.65v/cell, land asap!!!

Or you can safely get rid of the battery, or use to charge other devices.....

Randy
10-17 08:03
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HereForTheBeer
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rwynant V1 Posted at 10-17 08:03
Once the battery starts gassing,  the internal resistance goes up and the MAH storage capacity goes down.  With the 96% reading......that's after the "surface charge" has worn off.

Watch this battery every time you fly it.  at 50% check your cell voltages.....each should be better than 3.75v/cell........when you get to 40%,  if your cells are reading below 3.65v/cell, land asap!!!

thanks, today was too windy to fly safely.  tomorrow should be okay ill put my mavic 2 up and see what 96% reading is in voltage, then 50% and 30%.  ill report back.  actually today i can do that maybe and cycle it down one more time..wont hurt

  im hoping it is just a reporting bug because nothing new going on with it, i think this started around the time of new firmware give or take so thats why im wondering.  also flight times seem about the same overall..  22-24 mins avg-ish about what i always gotten with my mavic 2 pro

also something to know i noticed my charging seems to take forever in last stages.. i used a kill a watt meter to monitor power consumption and seems to chrge below 10 watts for about 20 minutes and i noticed that my charging time takes almost 2 hours. according to DJI's material should be about 1.5 hours is less time then mine takes.  wondering if its sitting at such a reduced charge level taking that long because battery maybe somewhat damaged like higher internal sistance or voltage droop?  im not sure usually a weaker battery charges faster in my experiance cuz less to charge
10-17 12:52
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HereForTheBeer
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so i did it, charged it and let it sit for a while and booted it up and 96% again.  my avg cell voltage is 4.33 volts.  not sure how that compares to whats normally the voltage for 96%  but that voltage seems healthy starting voltage.  can anyone confirm what avg cell voltage should be for 96% should be?  
10-17 19:47
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fans48f0c1a5
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I am getting 4.28v at 99% on one batt and 4.18 at 90%. I have noticed that second batt seems to drop more over a couple of days than the other. At least it is over 4volts so I don't know it it makes much difference. Both batts are 37 and 43 charges.
10-18 07:00
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rwynant V1
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Be sure to check cell voltage under a load ( flying )  The static voltage readings can be WAY different than under a load......this shows how "strong" your battery is.

Randy
10-18 08:22
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HereForTheBeer
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rwynant V1 Posted at 10-18 08:22
Be sure to check cell voltage under a load ( flying )  The static voltage readings can be WAY different than under a load......this shows how "strong" your battery is.

Randy

hovering in my living room it only drops to avg of 4.31V  hmm
10-18 10:40
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HereForTheBeer
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fans48f0c1a5 Posted at 10-18 07:00
I am getting 4.28v at 99% on one batt and 4.18 at 90%. I have noticed that second batt seems to drop more over a couple of days than the other. At least it is over 4volts so I don't know it it makes much difference. Both batts are 37 and 43 charges.

this interesting.. so there does seem to be something interesting going on with reported power levels.  not sure if they are attempting to come up with some sort of anti-wear logic by reporting lower percentage than actual.  

im only at 45 cycles as of this morning but i have a feeling im pushing my aircraft harder than most people do alot of sport move take offs and chasing stuff and ignoring landing prompts..so if it is some anti-wear logic that makes sense for me as well to have triggered it.  showing that it have weaker battery than i really do will mean have to land sooner.  
10-18 10:53
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HereForTheBeer
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interesting new update: i switched devices back to my iPad from using my iPhone and 99%-100% for 4.33V but on iPhone it shows 96%.  the plot thickens.  now im not sure if is designed to do that and just isnt syncing the changes to the aircraft/controller so stays localized in the app or if its a bug..
10-18 18:24
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