Mark The Droner Posted at 2018-8-13 04:10
Common sense is the LAST thing you'd want to rely on.  Common sense is why all these new folks are launching with partially charged batteries and losing their aircraft due to unexpected drops.

Knowledge and experience beats common sense in this case.

I guess common sense is a thing of the past-Good Luck People

"I know Nigel disagrees, but I like to table discharge my batteries to between 5 and 10% before I charge them, I BELEIVE this adds to the life of the batteries. (Like I said I purchased my a P4 in January 2017 and the batteries still show a 80% battery capacity)"

If my batterys from 2017 showed 80% capacity - I would start to look at why I have so low % capability.

I have batterys from when LiPo's became general use in RC ... still functioning ... I have 2014 ... 2015 LiPo's still punching high power performance 3D / EDF models around - and they do not fly well on partial batterys !!

Lets put this as simple as possible :

LiPo's do not rejuvenate or recover any capacity regardless of discharge routine.

LiPo's damage is accumulative and irreparable.

LiPo's suffer damage by deep discharge ... to high a rate of discharge .... over-charging ...  over discharging ..... heat ..... pressure ..... physical of course.

You are very lucky that DJI have installed a cut off in the battery FW that prevents you from discharging past ~3.0V per cell. Discharging to 8% as you do is :

1. Creating a greater % in the Life Cycle count. Life Cycle of 200 is based on 200 FULL cycle charges. That means people who charge from 30 ... 40% or whatever are NOT incrementing the cycle count by a full 1 life each time ... but you discharging to 8% each time are basically creating a full charge cycle count or near so.
2. Each time you do that - you cause a small increase in Internal Resistance which in turn resists charge - gives you your reduced capacity, causes greater voltage drop in flight and shortens flight time.

To finalise : LiPo are not like NiCd where deep discharge can give back some battery performance. LiPo's are completely different and lost performance is permanent.

Sorry but fact. Not a case of disagreeing with you - its a case of I am stating fact.

Nigel

ATJ Posted at 2018-8-13 04:14
I guess common sense is a thing of the past-Good Luck People

Bad wording ... common sense .... c'mon ....

I wish you good luck because I fully expect that your LiPo's will fail a lot earlier than another persons who treats them better. Your treatment of your LiPo's is literally just following the old NiXX road and detrimental to LiPo format. 80% for a 18 month old pack is not good at all ... I could accept if you literally flew that same pack literally every day ... but even then its not good.

A 200 cycle battery as the DJI are supposed to be should for the average flyer who uses about 60 - 70% of battery capability (ie lands at about 30 - 35%) ... that would give 400 - 500 charges (its not a linear calculation and my number is based on asking around fellow DJI flyers and my own observations and that many flyers do not fly to 30% all the time).

I have P3 batterys older than Jan 2017 and still charge up to 97 - 99% (100% before drop-back).

Doesn't that tell you anything ?

Nigel

solentlife Posted at 2018-8-13 04:43
Bad wording ... common sense .... c'mon ....

I wish you good luck because I fully expect that your LiPo's will fail a lot earlier than another persons who treats them better. Your treatment of your LiPo's is literally just following the old NiXX road and detrimental to LiPo format. 80% for a 18 month old pack is not good at all ... I could accept if you literally flew that same pack literally every day ... but even then its not good.

It's a loosing battle with you Nigel. Obviously you do not know the difference battery life (I call it capacity or memory) and charge level. My charging level is 100%. My battery life is 80%. Look at the manual so you will know the difference. Page 31 of the P4 Manual

  

Checking the Battery Level

  

The Battery Level Indicators display how much power remains. When the battery is turned off, press

  

the Power Button once. The Battery Level Indicators will light up to display the current battery level.

  

Battery life

  

Battery life refers to how many more times the battery can be discharged and recharged before it must

  

be replaced. When the battery is turned off, press and hold the Power Button for 5 seconds to check the

  

battery life. The Battery Level Indicators will light up and/or blink for two seconds, as shown below:

  

ATJ Posted at 2018-8-13 08:52
It's a loosing battle with you Nigel. Obviously you do not know the difference battery life (I call it capacity or memory) and charge level. My charging level is 100%. My battery life is 80%. Look at the manual so you will know the difference. Page 31 of the P4 Manual

  Checking the Battery Level   The Battery Level Indicators display how much power remains. When the battery is turned off, press  the Power Button once. The Battery Level Indicators will light up to display the current battery level.   Battery life  Battery life refers to how many more times the battery can be discharged and recharged before it must  be replaced. When the battery is turned off, press and hold the Power Button for 5 seconds to check the  battery life. The Battery Level Indicators will light up and/or blink for two seconds, as shown below:

For a more accurate value, you can check in the flight logs, for example the log file for my last flight has the following values:
CENTER_BATTERY.fullCapacity [mAh] = 5180
CENTER_BATTERY.loopNum = 62

This is for a 5350 mAh battery. 5180/5350 = 0.968 = 96.8% original capacity for a battery with 62 full recharge cycles or 203 flight logs that was new in April 2016 and has flown around 120Km.

I agree with Nigel that discharging a lithium battery before recharging will only shorten it's lifespan with no gain.  I don't do that, although I do often, maybe normally, fly until the battery is around 12%.

Nigel_ Posted at 2018-8-13 09:37
For a more accurate value, you can check in the flight logs, for example the log file for my last flight has the following values:
CENTER_BATTERY.fullCapacity [mAh] = 5180
CENTER_BATTERY.loopNum = 62

I think what we are all missing here is.

Lithium Ion and Lithium Polymer batteries do not normally come with electronics attached to them, therefore they should be charged and maintained according to Nigel’s (solentlife) posts.      

DJi batteries do have electronics attached to them, hence “Intelligent Flight Battery” and should be charged and maintained according to DJi’s specifications and instructions.

ATJ Posted at 2018-8-13 08:52
It's a loosing battle with you Nigel. Obviously you do not know the difference battery life (I call it capacity or memory) and charge level. My charging level is 100%. My battery life is 80%. Look at the manual so you will know the difference. Page 31 of the P4 Manual

  Checking the Battery Level   The Battery Level Indicators display how much power remains. When the battery is turned off, press  the Power Button once. The Battery Level Indicators will light up to display the current battery level.   Battery life  Battery life refers to how many more times the battery can be discharged and recharged before it must  be replaced. When the battery is turned off, press and hold the Power Button for 5 seconds to check the  battery life. The Battery Level Indicators will light up and/or blink for two seconds, as shown below:

SDuggest you go back and read what YOU posted :

Quote :

Like I said I purchased my a P4 in January 2017 and the batteries still show a 80% battery capacity

Unquote.

Where does that say battery LIFE ??

Losing battle (yes spelling) ... where ?

I fully accept that 80% CYCLE LIFE is ok ... but YOU wrote 80% battery CAPACITY ....

Dum tee Dum tee Dum .... if I was a rich man ... doo be doo be doo ....

Nigel

Nigel_ Posted at 2018-8-13 09:37
For a more accurate value, you can check in the flight logs, for example the log file for my last flight has the following values:
CENTER_BATTERY.fullCapacity [mAh] = 5180
CENTER_BATTERY.loopNum = 62

He'll be having a go at you now ... he writes Capacity - and then claims he means Life Cycles ...

Nigel

ATJ Posted at 2018-8-15 02:43
I think what we are all missing here is.

Lithium Ion and Lithium Polymer batteries do not normally come with electronics attached to them, therefore they should be charged and maintained according to Nigel’s (solentlife) posts.      

Trouble is me'ol chap ... DJI have admitted themselves that they have not updated / rewritten their advisorys on battery maintenance.

Why do you think that moderators have come around to similar advice as many give here similar to mine ?

I agree that if a newcomer to the hobby knows nothing else and does not frequent forums to ask such questions - then follow DJI's uncorrected advice.

Nigel

solentlife Posted at 2018-8-15 06:30
Trouble is me'ol chap ... DJI have admitted themselves that they have not updated / rewritten their advisorys on battery maintenance.

Why do you think that moderators have come around to similar advice as many give here similar to mine ?

Sorry Nigel, I'm not perfect like you?

ATJ Posted at 2018-8-15 08:37
Sorry Nigel, I'm not perfect like you?

We can all see that perfectly clearly.

Now go annoy someone else.

Nigel

solentlife Posted at 2018-7-28 05:30
ALL batterys suffer usage .. and the term 'Memory' is a term that got abused and became accepted fact instead of reality ... Batterys do not actually get a memory as some claim ... NiCd days - this was a constant argument ... what actually happened was repeated partial discharge, it was nothing to do with charging, caused a chemical and physical limitation to be created that needed full cycling to break. LiPo's are resistant to this phenomena.

LiPo's as with ALL batterys have Internal Resistance. This increases with cycles of use until eventually the battery cannot deliver the power asked of it ... temperature goes up ... it swells etc.

"Discharging a LiPo cell past 2.8V causes physical damage. This is why the max 3.0V figure has been established. Due to voltage drop in use .. this is then revised to 3.3V in use"

This is a so so explanation... 
It has a logically inverted meaning. 
Must be revised so:

Discharging a LiPo cell below 2.80V causes internal damage by unwanted chemical reactions. 
This is why the min 3.00V figure has been established. 
Due to the voltage drop during the strong discharge of the flight, the safe lower limit for a Li-Po and Li-HV battery must be pointed at around 3.30V, if not a bit higher, even 3.50V. 
The remaining power between 3.30V and 3.50V is always very little, few units of %, maybe less than 10%.

Just to be clear:

It's not a good idea to refer to voltage relative to power % because the voltage varies up and down depending on demand, the percentage only goes down.  See the mAh data.

When a cell hits below 3.5 volts, the pilot will get a warning of low battery.  It doesn't matter what the percentage of power is reading.

When a cell hits below 3.3 volts, the aircraft begins to auto-land in a last desperate attempt to save itself.  This is regardless of the percentage of power or the mAh reading.

When a cell hits below 3.0 volts, the battery shuts itself off regardless of the aircraft's location or whether it is airborne.  The percentage of power reading does not matter.  

This is why you want to fly with a healthy balanced battery.  Always launch with a fully charged battery.  And flying gently the last half of the flight is not a bad idea.  

Good luck

Honestly, even if someone will say I'm stupid, I think more than half of my flight in these years have been done with not fully charged batteries..
it's true, a drone can be a serious hazard so have fully charged batteries can help to avoid it, but batteries are batteries..they can be used even  if not fully charged!Obviously, if not fully charged, I'm keen to don't  stress  them so to stay away from low voltages that can cause problems!
I didn't do that on purpose, but often happens that I move between near places so there is no time to  charge batteries and also, even if the discharge time is set to  2 days, is more dangerous for the batteries to often keep them full charged.
Anyway, I charged them only the hour before  I'm gonna use them!

I agree with what you're thinking. You can use the batteries until they're drained out. BUT! No big deal if a tablet or phone stop working due to low batt. If this happened to drone in the air, it will fall down on whatever is on the ground. The consequences can be so serious that at least minimum you can do to avoid that is start with fully charged bat. at take off.
I also find myself in situations where the only way to make some shots was to start with partial drained batt. But you mast be aware that in such situation you must not rely on percentages displayed on  screen.
It is also important how long had been such bat. partially drained when you intended to use it again. If that was in the same day no problem. After several days it's too risky. The drone will nod fly slowly because of battery going to its end but it will instantly shut off when it reached certain low level of voltage and it is far from being completely drained out.

exactly...even if the battery voltage on the display may be not so accurate, my advise is to always keep it on sight because, especially with hard acceleration or with low battery, if one cell reaches 3V the drone will go down..and that can happen independently if the battery is new or old o charged or not..
also, always analyse battery graphs..