How many flights you can get from a phantom 2 battery If you use it properly!

There is not really a limit, just that after each charge / discharge cycle the percentage of charge goes down and so the flight time will become shorter over time.

I have had a battery go bad after 45 cycles, others at 100 and 110 cycles. DJI say 300 cycles is lifetime. But I don't know of any yet making it to 200. To expend the life store battery at 50% and every 20 cycles discharge to 8 % the fully charge before use. Any batteries that bulge replace.

johnwarr@live.c Posted at 2015-7-18 03:18
after each charge / discharge cycle the percentage of charge goes down  ...

Maybe more accurate to say over time capacity goes down;  I now have over 20 cycles on my two, and one says its capacity is >5500, the other >5450mah  (new of course is =5200) .  Eventually I am sure they will begin the downward spiral.

roy@mcscomputer Posted at 2015-7-18 07:44
I have had a battery go bad after 45 cycles, others at 100 and 110 cycles. DJI say 300 cycles is lif ...

I never discharge my batteries to 8%. That is bad for the battery. The standard for LiPos is 80% max, and almost ever battery manufacturer will tell you that.

This article talks about LiPos and discharge %.
LiPo Discharge
On my RC aircraft I also never let my battery cell drop below 3.7 volts. I monitor the battery pack voltage of my RC vehicles while in flight so I never over discharge my batteries.
In this case the battery pack is made of two 22.2 volt 6S batteries. That means at 22.2 volts each of the 6 cells has 3.7 volts. At full charge the 2 batteries in series will produce 50 volts. Each cell has 4.16 volts. 12 x 4.16 = 50.

Your Phantom battery is a 3S 11.1 volts battery. 3 x 3.7 = 11.1. Fully charged that battery is about 12.5 volts. 11.1 volts is discharged. Some folks take their batts lower than 3.7 volts, like 3.3 or 3.2 per cell, but I never do, and most batt manufacturers will recommend you don't either if you want your batts to last.

I guess the engineers are telling us wrong from DJI since on page 10 of the manual they say that after 20 cycles to discharge the battery to 8 % of power or until it can no longer be turned on..  If the standard for lipo's is 80% does that me we would only get to fly for 20% until we need to land. Something is not comming up correctly here. Could you clarify the  discharge of 80%. Do you mean to not discharge the battery below 20%?

I agree with the 8% is wrong from dji marketing or whoever came up with it.  

The lipo rule of thumb for long life indeed is use top 80% of it - NEVER take it below 20% charge left.  THIS is how to keep it working the longest I believe.  I will never ever do that 8% bit.  I have two batteries and am not professional photographer and enjoy 10 minute flights.  I think that is why my 20+ cycled batts today show about 6% MORE capacity than new.

JATO Posted at 2015-7-19 10:16
I never discharge my batteries to 8%. That is bad for the battery. The standard for LiPos is 80% ma ...

Well there is a big difference between the batteries with integrated "intelligent" circuits and "non intelligent" LiPo RC batteries.  The "intelli" batteries like the ones used for the P2 have under voltage protection and the percentage range shown is based of the usable range between programmed LVC (low voltage cutoff) as 0% and 100% charge.

There is no difference, underneath it is still a multi-cell LiPo battery. The fact that DJI tells you to discharge to 8% is not good for the battery.  I would much rather manage the battery myself than have DJI do it.
The bottom line is this:

The lower the current draw the longer the pack will last.
Charging to less than 4.2V/cell increases cycle life.
Discharging only to voltages well above the LVC increases cycle life. (Stop flying before LVC kicks in)
Cooling battery increases cycle life, don't charge hot.

JATO Posted at 2015-7-19 23:13
There is no difference, underneath it is still a multi-cell LiPo battery. The fact that DJI tells yo ...

Again you're basing it off standard RC LiPo batteries without the integrated inteli/smart difference.  True the cells are the same but there is a charge/discharge controller integrated into the P2 battery whereas that does not exist with normal LiPo RC  batteries you you likely use for your electric helis.  Please tell  what  0% charge means  for a P2 LiPo battery.  What cell voltage is that?

PanamonCreel Posted at 2015-7-20 03:29
Again you're basing it off standard RC LiPo batteries without the integrated inteli/smart differen ...

I HAVE read where people have discharged their batteries to 8% and bricked them.
I am curious but by no means as advanced as you seem to be.  But reading this confuses me and intrigues me at the same time.

So you're saying that because of the programming in the batteries circuitry, the programming will prevent the battery from being discharged too deeply and that the same intelligent circuitry knows to consider the LVC range rather than the entire capacity of the battery?

Wouldn't that also imply that the intelligent batteries do not report their actual capacity and state of charge to a connected charger but rather a calculated capacity and voltage based on the programming in it which was designed to protect both the battery and the Phantom?

What happens if that circuitry has a bug?

Panama, I think you are misleading folks with your comments.  Being a 'smart battery' has nothing to do with lipo life.  Our dji 'smart battery' simply means the charger and discharger are inside the battery instead of external.  NO DIFFERENCE in the end.

You can argue what 0 means, what 'is' means, what 80% means, but at the end of the day, lipo cell chemistry does not do well discharging below about 20% minimum.  dji marketeers have somehow come up with a magic 8% number:  this does not jive with known chemical lipo topology.  Yes, they sell this battery, they call it 'smart' but they are flat wrong to tell anyone to discharge it to 8% based on proven engineering data.

Please remember dji is not the know all people who know more than everyone else in the world.  If you need reminders, remember they shipped pre 2.1 ESC controllers that instantly self destructed if stalled.  Then they fixed that but still did not get it totally right and now ship esc 2.1 units that do not self destruct, but rather have an instability that causes them to throw props that are only hand tightened.  If not a thrown prop, they have no control over current if you crash land and let the buggers melt the case - absolute cave man technology!  They are not gods.

Discharging today's lipo batteries to under 20% will eventually harm them.  FACT.  

Panama, if you want to continue on how dji is not the perfect company, how about their 300 cycle battery life?  Let's discuss that.  Most folks get 20-50 cycles and the batteries are then done.  WHY?  

Many theories have been suggested, but the bottom line is here is a company that sells over $ 100.00 'smart' batteries that are so dumb they fail in less than 10% of rated life!

I say it is because they have a crappy none effective balancing circuit that lets the cells get out of balance so far the whole battery becomes NFG at these low cycles.  

yorlik Posted at 2015-7-20 05:13
Panama, if you want to continue on how dji is not the perfect company, how about their 300 cycle bat ...

Where did I say that DJI is a perfect company. Seems like you are reading imaginary things.
Their cell quality, cell matching and C rating are certainly questionable and failures are also seen prior to one of the deeper discharges but that still doesn't change the fact that there is a difference in how inteli/smart (present in many consumer electronics, e.g. Laptop batteries) and your run of the mill RC-LiPos.

PanamonCreel Posted at 2015-7-20 06:04
Where did I say that DJI is a perfect company. Seems like you are reading imaginary things.
Their  ...

Again I will tell you there is no difference.
One of my P2v+ batteries with 40+ cycles, as measured on a DVM:

Fully charged per 5 battery bars @ 100%,  and shows 99% per DJI Vision software:
12.23 total volts, 4.07 volts per cell (assuming all cells are balanced).

80% discharged per 1 remaining battery bar and shows 80% discharged per the DJI Vision software:
11.1 total volts, 3.7 volts per cell (assuming all cells are balanced).

Any further discharge will drain the cells past 3.7 volts per cell, which is again bad for the battery and the lowest voltage the battery should be operated at. A 3S 3.7volt per cell battery is considered discharged at 11.1. Draining it to 8% per the DJI Vision software will damage the battery, each and  every time it is done, thus shorten it's life.

Panama Posted at 2015-7-20 06:04

there is a difference in how inteli/smart (present in many consumer electronics, e.g. Laptop batteries) and your run of the mill RC-LiPos.

JATO Posted at 2015-7-20 06:41

Again I will tell you there is no difference.

Panama, there is no difference.

JATO Posted at 2015-7-20 06:41
Again I will tell you there is no difference.
One of my P2v+ batteries with 40+ cycles, as measure ...

Draining a LiPo below 3.7V is bad for them,  where do you get that info from???

3.7 Volts is the nominal voltage under load.  LiPo manufacturers give between 3.3-3.5 Volts per cell for LVC (varies by manufacturer/distributor,  e.g SPC -3.5V, Thunder Power 3.3V) .  The P2 batteries I measured cut off (0%) at around 3.3V/cell (9.9V total)  so on the low end but still nothing unheard off.  You will even see some mentioning of not below 3.0V per cell but that is usually for no to very low current loads.  
So as such the below 8% discharge for capacity meter calibration of the P2 battery should not damage the P2 battery as long the cells are in good health to begin with.

yorlik Posted at 2015-7-20 07:03
Panama, there is no difference.

sure there is and that one is huge especially on a safety stand point

You can discharge a non smart/inteli LiPo down to a dangerous low voltage level that causes electrolyte degradation to a level where it may vent toxic and flammable gas, cause internal shorts and may self ignite.  You can also severely overcharge a non smart/inteli Lipo battery ( wrong settings on the charger) which may also result in cas venting and/or fire.  
A  properly functioning battery internal smart/inteli circuit prevents both of these dangerous user errors to occur.

Yes there are theoretically batteries that you can take to 3.3/3.2 or even 3.0. My RC controller allows that but I know better than to do it.

Bottom line is they are your batteries treat them as you want. But there is no difference, period, regardless of what you say.

Panama, I think we are arguing over semantics and saying the same thing.  

It appears you are arguing that a smart charger/discharge_monitor, such as in our dji batts, is safer than not having such smarts.  OK.  I don't think anyone will argue that.  

But your writing makes it appear you are saying the lipo chemistry used in dji is different than all other lipos, and that is flat wrong as I am sure you can agree.  

THAT is what we have been arguing with you - the dji batt lipo is same as the rest in the world, NO DIFFERENCE.

NOw, that said, let's go on to the other points you mention last....

You say 3.7v is nominal, not 20% charge left point.  Sounds reasonable, but neither you or anyone else has put up the exact charge and discharge voltage curve for the dji batteries.  As again I am sure you know, lipo designs ARE slightly different from mfgr to mfgr, and if you google lipo charge or lipo discharge curve, you can find many examples - SOME of which show 20% remaining charge @ about 3.7v. It is a function of the EXACT chemistry used.  

But beyond that, the other post stated clearly that this 80% USED, AKA 20% left point, IS SHOWN IN ASSISTANT AND ON OUR DJI BATT LITES AS 1 LITE AND 20% REMAINING.  I don't think Jato made that up;  he is relating what dji THEMSELVES call 20% remaining for THEIR battery as identified by the 1 lite left and assistant actual data.  Not arguable point other than questioning if there is error in Jato's observations.  NOw if you personally disagree with dji's assessment of THEIR battery 20% & full charge points, I am not sure how far you will get getting past the marketeers who seem to have way too much input into engineering in this company, but if you DO get hold of a real charge and real discharge set of curves for our 5200mah batteries, I for one will love to see it!