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Cycling Phantom Batteries
2700 15 2015-4-14
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smatchet42
lvl.3

United States
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Does it hurt to cycle these batteries more often than the once every 10-20 charges specified by DJI? With one of the "Smart PowerChargers", it would be possible to discharge and recharge after every use, especially if the batteries were going to be used, say, every other day.

2015-4-14
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jtrjr
Captain
Flight distance : 4341 ft
United States
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Smatch,

I'd like to hear some experts chime in on this as well. It's time for me to do this process on I'll 4 of my batteries and I'm half afraid to do it. The old saying "If it works, don't fix it" comes to mind because I haven't had a single battery issue yet (knock on wood).

Jerry
2015-4-14
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PanamonCreel
Second Officer

Mexico
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Don't do it more often as the DJI recommended frequency, the reason behind this lower discharge is to calibrate the internal capacity meter to the irreversible capacity loss the battery gets over time and charge cycles and doing it more often will put more stress on the battery than necessary .  
2015-4-14
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timf419

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My understanding, since these are hiTec batteries the need to 'truly' cycle the battery is not necessary for the proper operation and charge strength (stamina).  Cycling the battery resets the parameters of the SMART circuitry - thus the level indicator is true.  Keeping the 'fuel gauge' properly sync'd with the actual battery charge prevents potential problems.

Again, I maybe wrong because these batteries will not (should not) start to have a 'memory'.  Rechargeable batteries of old, had the potential to get a memory of its' charged range.  If the battery never went below 1/4 charged - the battery would eventually 'think' 1/4 charged was empty.  To prevent this memory issue, you would allow the devise to completely discharge, I mean empty.  Then you would fully charge the devise - no don't unplug it after an hour, really charge it.  This would happen with the old Motorola StarTec phones.  You could get a couple days out of a fully charged phone if the battery was maintained.  Otherwise the battery would last less and less time even though it had been fully charged, overnight.
2015-4-14
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CryoEng
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timf419 Posted at 2015-4-15 09:35
My understanding, since these are hiTec batteries the need to 'truly' cycle the battery is not neces ...

Lithium Polymer chemistry does not have the NiCad memory.  The discharging is for resetting the circuit baseline, as you mentioned.

LiPo cells should not be discharged below about 3 volts.  The electrolyte can begin to vaporize which means it can't be recovered.  (Packs "puff up...")  I'm not crazy about the need to do the full discharge step for this charging system.  I will likely avoid doing that.

I use LiPo packs on small satellite systems and there is continuing effort to design intelligent charging and discharging circuits.  None of them require low level discharging, for any reason.  Nor should they.

Cheers!
2015-4-14
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jtrjr
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Flight distance : 4341 ft
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So do you guys think I should do the recommended discharge on my 4 batteries? I understand that I'm soliciting your opinions. I've been a bit concerned about it because I'm going over the 20 cycles but again, I've made the mistake of fixing something that didn't need to get fixed before. I just want to get all the info I can before I make the decision.

Thanks,

Jerry
2015-4-14
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davidw1963
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Dumb question.. How do you actually "discharge" them fully? Turn the Phantom on and let it "run" without the motors spinning? Ive turned the batteries "on" by mashing the button, but they turn back off after a few minutes.
2015-4-15
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Swerve
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United Kingdom
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davidw1963@att. Posted at 2015-4-15 18:39
Dumb question.. How do you actually "discharge" them fully? Turn the Phantom on and let it "run" wit ...

I discharge by leaving the battery in the Phantom, switched on but motors not running, overnight (with props off)
You can also run them down quite quickly by just hovering. Can get a bit boring though.
2015-4-15
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davidw1963
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ok. I was just wondering if had to be done a certain way. There is a place I can fly to "kill" them without worrying about a crash, etc. LOL.
2015-4-15
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PanamonCreel
Second Officer

Mexico
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CryoEng Posted at 2015-4-15 10:13
Lithium Polymer chemistry does not have the NiCad memory.  The discharging is for resetting the ci ...

The battery internal circuit won't allow for damaging low level discharge and has LVC to prevent that from happening.  So a 0% indicated charge level is still supposed to be above damaging low voltage levels however I'd avoid high discharge rates for going to the below 8% since it seems that the LVC doesn't take out of balance cells into account.
2015-4-15
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yorlik
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CryoEng Posted at 2015-4-15 10:13
I use LiPo packs on small satellite systems and there is continuing effort to design intelligent charging and discharging circuits.  None of them require low level discharging, for any reason.  Nor should they. ...

cyroeng,  will YOU be discharging YOURS every 20 times?  or any times at all?
2015-4-15
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nrgwise
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I posted a discussion about batteries in another thread...I would absolutely recommend discharging and recharging at the DJI recommended frequency for these batteries.  If you don't have a load compensating charger/deep cycle charger, then flying is the best way to get the voltage down. And when low, a low, controlled hover is the best way to get the level where you want.
2015-4-15
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jtrjr
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nrgwise Posted at 2015-4-16 09:39
I posted a discussion about batteries in another thread...I would absolutely recommend discharging a ...

Chris,

Did you do yours yet? When I fly I cycle from battery 1 through battery 4 in order pretty much all of the time. My batteries are all just over 20 cycles. I read somewhere between 20-30. I'm hoping to fly all day tomorrow and I don't want to jinx things by doing this right now but I don't want to wait if it's critical to do it now. With any luck I'll probably cycle through those batteries 4-6 maybe as many as 8 times tomorrow. Decisions, decisions, decisions...

Jerry
2015-4-15
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CryoEng
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yorlik Posted at 2015-4-16 07:18
cyroeng,  will YOU be discharging YOURS every 20 times?  or any times at all?

I don't plan on intentionally discharging the Phantom batteries to low levels of charge.

The systems I work with have very hard thresholds and simply will not allow the battery cells to discharge below 3V.  Without some charge to bring them back above that level, the system is dead on orbit.

As far as the battery chemistry is concerned, there's just no good reason to drain the battery to low levels.  Only risk.  If the charging/monitor circuit takes care of that threshold, well... ok.

I'm not certain I trust the average "RC hobby system" charging system circuitry.  I know how much effort goes into the satellite battery systems.

Cheers!
2015-4-16
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nrgwise
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jtrjr@yahoo.com Posted at 2015-4-16 09:50
Chris,

Did you do yours yet? When I fly I cycle from battery 1 through battery 4 in order pretty  ...

Jerry,
I have not deep cycled them yet.  I only have 12 charges on each.  I too fly them in order 1 through 4 all the time.  However, I keep meticulous records so when I hit 20 cycles I will do it without hesitation.  I also bought one of those 4 battery chargers with the deep discharge function.  I will be using that.

I wouldn't say it is critical to do it at exactly 20 charges.  But I would not go to 25 and not do it.  If I knew I was going to be away or something, I might do it as early as 18.  But I think those would be my limits.

Chris
2015-4-16
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yorlik
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cyroeng, thank you for your reply.  As an engineering who has used hi power lipo batts, I have faith in your experience.   

it would be great to be able to compile list of those who DID discharge every 20 cycles vs those who did not.... vs who has batt go bad when....

after going over 2yrs with near perfect lipos in my EV, then discharging heavily and 4-6mo later killing 10% of them, I will follow your lead and NOT do it.  

I am at about 18 cycles per assistant, and both my batts show significantly HIGHER capacity than new still!   I do not think I have ever gone below 50% charge yet....

if the day comes that my full  capacity starts showing <5000 I may, but not until then.
2015-4-16
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