Battery Woes?

[DLinzy]

My P2V+ hates 3 of my 5 batteries. They have all been charged and discharged correctly via the light bulb circuit until they won't turn on anymore and they all charge to 99+ %.

So Battery #1 #2 & #3 perform the same in 2 Drones and all contacts have been cleaned.

Start the drone, acquire sats, GPS lock home lock every thing good and launch!

30 - 45 seconds later - I've learned to hover it about head high.. Green LEDS turn RED and it starts down.

I hand catch it and within 10 or so seconds it shuts off on its own. but the battery LED's are still blinking All 4 of them.

Bring it inside, hook it up to the PT S/w and here are the results:
Voltage 12116 mV Current -997mA
Design Capacity 5200 mAh Temperature 31.00
Full Capacity 4392 mAh Serial # 42878
Current Capacity 3490 mAh
Cell 1 Voltage 4059 mV
Cell 2 Voltage 4050 mV
Cell 3 Voltage 4009 mV
% of Charge 79%
Discharging Times: 18 Times

Does anyone have any idea?

I've sent the above pics to DJI - and I have an open Ticket, just wondering what my options are at this point for these 3 batteries.

TIA,
Denny

 

[PaulSouthport]

997 mA static draw looks a bit high.
Full capacity at 4392mAh looks well out of range.
Cell voltages all appear balanced and reasonable.

Any add ons to the quad that take power? lights/DVr etc.
Somethings not right if full capacity is that low...

 

[DLinzy]

Nothing, totally stock.

 

[yorlik]

997ma idle is perfect.

3490/4392= 79% capacity left, yep right on.

So the bus is doing its job nicely.

The cell 3 being 50mv low, combined with your description, tells me most likely one of cell 3s cells is bad.

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[yorlik]

Iirc, these r 2+ yrs old. With typical handling, I expect remaining life after 18 full charge cycles to lower capacity this much.

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[yorlik]

I offered in ur other thread to check one of these for u and report back why ur issue. .. offer still stands.

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[Mark The Droner]

I would fully charge the battery and then look at the specs.

I don't see a problem with the cells. According to healthydrones, the lowest cell should be within .07 volts of the next lowest cell, and .07 volts is 70 mv. You're only 41 mv which is fine. However, the cell voltage differences will normally increase as the voltage drops. Nonetheless, it appears your cells are relatively balanced.

Full capacity 4392 mAh is way too low for a battery that is supposed to have 5200 mAh.

I think the battery is just old and should be retired. MHO

 

[DLinzy]

Ok, fully dis-charged and charged... removed and installed in drone and took pic.....

 

[DLinzy]

This is my good battery for comparison...

 

[Mark The Droner]

I gotta stand by my post above.

I had a battery I retired a couple weeks ago... I had it almost a year - 31 cycles - supposed to be 5400 mah, it showed max as 4850 mah, and the cells were out of balance by 100 mv. So I'm done with that one.

 

[yorlik]

I would say it should be fine accept empirically you know it only last 2 minutes. So something is wrong. Best clue to me is still the 50 millivolt+ variation, pointing to potentially bad cells.

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[RoyVa]

You can't always go by what the paperwork shows. I had a battery that indicat d it was ok too. However in flight after three or four minutes it would drop from 90 % to 65 then in one muni te drop to 10% and auto land due to critical battery level. Bring it back charge again and same thing. Showed good but definately a bad battery. Almost cost me a loss the second time due to auto landing in woods.

 

[DLinzy]

Agreed with all above, in the "Salvage" pile of broken parts they go to maybe one day be recycled into something useful, I just can't throw anything away.

DC

 

[David Bruce Kerr]

It looks like you have a bad cell on number three.


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