battery damaged problem

[scorpiopaulius]

So my journey with phantom 4 going not very well... I had bad flex cable, fix it, cracked body - glued it and now I take it outside and after 10min flight got battery damaged error... ****... it was like 46%... so I turned off battery and went for google information. and got some suggestions to discharge completely and charge full couple of times... "ok' I said... popped battery back in, power it on, ofcourse got battery damaged error , but wait... I cant turn motors ON... jesus... now Im sitting with turned on drone... and have no better idea how to completely discharge them in other way... :/ on battery info one cell 3.7V, other like 4.1V... new battery ata local store - 170 euros... I tried look for used - no result its like rarest thing in the world? 90USD from aliexpress... ofcourse knock-offs but still maybe it will work... jesus, now I know why I paid 350euros for drone... by the way, battery is 107 cycles of recharge...

 

[scorpiopaulius]

So trying discharge just by leaving it ON, but cell voltage difference is worrying me

 

[scorpiopaulius]

So I "drained" battery. Drone turned off itself, After powering it ON it should down itself. OK, I put it to charge. like after hour I saw it third from left LED blink twice on repeat... google it and its say overvoltage protection... ok, I put it to test. put in drone, and it showed me 100% :O wow , I thought... but after cheking voltages got me surprized. all cells were equal but around 3.8V. So I thought some think not right. so I let it hover. got about 11mins , battery dropped from 100 to 18percent and got battery damage again, and again CELL2 was much lower then rest and CELL3 was much higher then rest :/ so now Im going to let it discharge again... **** I feel unlucky...

 

[Hemul]

Discharge via ceramic resistor? (200 ohms and 5 watts) as an example. Before of course search for plus and minus contacts with a multimeter. Slow discharge ... Resistance can get hot, Caution! My proposition.

Translated from German in English with Google translator

 

[scorpiopaulius]

So second discharge and I put to charger... after like 30mins it stopped charging. popped battery in drone and saw this view...

Battery balancer not working?

 

[Fly Dawg]

all cells were equal but around 3.8V. So I thought some think not right. so I let it hover. got about 11mins , battery dropped from 100 to 18percent and got battery damage again,

Upload your .txt flight log from this hover test. We can then see the initial battery information and the rate of drop, to determine more accurately if this indeed is a bad battery as it appears to be. You can upload at the link below and share a link back here to that and we can assist you.

Log Viewer

 

[scorpiopaulius]

This was first flight when I saw battery damaged DJI Flight Log Viewer - PhantomHelp.com
I was trying OA near walls, to look how they work in action.

then hover test: first fly until I landed DJI Flight Log Viewer - PhantomHelp.com
and second fly after I landed DJI Flight Log Viewer - PhantomHelp.com
in second take up you can see that cells again started go crazy.
Now Im trying to charge them again... but strange thing, I always watching them how much power from the 'wall' they taking in Watts. When they start it goes like 100-120W I believe and then near end they go like ~20W. No 4 bars lighting up , like near the end and it still drawing ~90W... maybe it charging that last cell... who knows... Im each minute check battery temperature with hand, not hot, little lukewarm... jesus it headache

 

[Fly Dawg]

Below is the plot from the original flight where you noticed the Battery damaged message. Cell 2 and 3 became unbalanced midway through the flight

Below is from your first hover test. There is not a great deal of cell deviation in this one.

Below is the last hover flight. Again Cell #2 and #3 became unbalanced mid flight. This one much more pronounced.

First suggestion would be to first try another charger. Preferably OEM. If this appears again you will know the cells are not holding a proper charge and balancing correctly which means get rid of that battery.

 

[Deleted member 120647]

As a matter of interest are the cells in phantom batteries in series with one another?
I would have thought so but maybe it is possible someone has designed a board that would take parallel voltages and combined them in series

 

[scorpiopaulius]

Thanks FlyDawg for graph. So charger this time charged fully(looks to me) and did again some hover(up an down) test.
hover 1: DJI Flight Log Viewer - PhantomHelp.com
hover 2: DJI Flight Log Viewer - PhantomHelp.com

this time cells voltage looks more acceptable I think. but percentage is way off... after hover 2 I left it again completely discharge until drone turned off and left to charge. Maybe it will fix the percentage issue. I will do tommorow more hover flights...

 

[Fly Dawg]

this time cells voltage looks more acceptable I think. but percentage is way off

In Hover 1, ( Below ) your percentage started at 38% and stayed there until well in to the flight. That is one I haven't seen before. To me that indicates a problem with the battery. Not necessarily the cells themselves but the internal control circuits which provide the information to the FC, prior to telemetry transmission. For informational purposes, you should not discharge these batteries below 8%.

 

[scorpiopaulius]

maybe you know how much voltages in cells are when they reach 8%?

 

[Fly Dawg]

maybe you know how much voltages in cells are when they reach 8%

Approximately 3.47V.

 

[scorpiopaulius]

So I did flight test with that battery... DJI Flight Log Viewer - PhantomHelp.com
now battery level and voltage seems OK...

 

[Deleted member 120647]

Make more than one test flight.

 

[scorpiopaulius]

Make more than one test flight.

Yeah, i will, just windy these days in my country

 

[cheddarman]

As a matter of interest are the cells in phantom batteries in series with one another?

Yes! Each cell is around 3.7v and these are same as a 4s LiPo battery, 4 cells in series giving about 15v

 

[Deleted member 120647]

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