Hello friends, in these last days I have been able to check 2 things and I would like to know if someone else can confirm this behavior.

I have 3 batteries, with which I can fly approximately 12 minutes (far from the promised 16 minutes). I always charge the batteries 100% with the original wall charger (110-240v > 5V 3A).

What I have been able to verify is that if after loading 100% with 5V 3A, I can still to continue charging it with 5V 2A and when it is finished I still can to continue charging it with 5V 1A. With less than 1A, the battery can not be charged.

This causes my batteries to extend charge to approximately 14/15 minutes instead of the original 12 minutes.

Has anyone tried this?

This is interesting information.  What adapters are you using to charge at the various amps?  Has anyone else tried this and what are the possible side effects tot the batteries?

How do you know when it’s at 100% ?

Lithiums are always charged with a tapering current, since they reach peak voltage before full capacity.

You have no direct control over the charging current - the circuitry inside the Spark battery does. Connecting different USB chargers with decreasing current capacities doesn't change anything at the final stage of battery charging. The current rating of a power supply (the "A" figure) doesn't mean that this current will flow no matter what. It means that your charger is able to deliver this much if needed by the device being charged. Like Bright Spark said, the Constant-Current/Constant-Voltage method is used for LiPo charging. The sole fact that you disconnect the charger and let the battery sit for a while, causes the battery voltage to drop a bit. When you re-connect the charger (it doesn't matter that it's a lower-rated one at this point), it takes a while for the current to drop again below the termination threshold, but the actual additional electrical charge that gets to the battery is negligible. As for the additional flight-time you seem to observe, I'd attribute it to flawed testing methodology, confirmation bias, placebo effect, etc.

Hi, guys. Spark can support QC 3.0 charger. If you charge your spark with 5V 2A, it will need more time to fully charge the spark. I would recommend you use QC 3.0 as it works more efficiently.

No harm in doing a test using the standard portable chargers.  Will try and post if i see any results

Sparky_17 Posted at 2018-1-3 12:56
This is interesting information.  What adapters are you using to charge at the various amps?  Has anyone else tried this and what are the possible side effects tot the batteries?

Just the USB adapters to charge smartphones (wall to USB or USB to USB)
In the market I can get chargers with output in 3A, 2A, 1A, 0.5A

heliman Posted at 2018-1-3 13:04
How do you know when it’s at 100% ?

Because the battery stop charging, the four leds are on when checking by touching the button, and it can't be charged with same Amps...

Zbig Posted at 2018-1-3 16:46
You have no direct control over the charging current - the circuitry inside the Spark battery does. Connecting different USB chargers with decreasing current capacities doesn't change anything at the final stage of battery charging. The current rating of a power supply (the "A" figure) doesn't mean that this current will flow no matter what. It means that your charger is able to deliver this much if needed by the device being charged. Like Bright Spark said, the Constant-Current/Constant-Voltage method is used for LiPo charging. The sole fact that you disconnect the charger and let the battery sit for a while, causes the battery voltage to drop a bit. When you re-connect the charger (it doesn't matter that it's a lower-rated one at this point), it takes a while for the current to drop again below the termination threshold, but the actual additional electrical charge that gets to the battery is negligible. As for the additional flight-time you seem to observe, I'd attribute it to flawed testing methodology, confirmation bias, placebo effect, etc.

Make sense, but there is not placebo effect at all.
I know there is a little discharge when disconnecting the charger, but I can still to charge the battery with less Amps instantly. It is not possible with the same (or higher) Amps.
I believe there is related with the charge speed/capacity...

S.J Posted at 2018-1-3 20:06
No harm in doing a test using the standard portable chargers.  Will try and post if i see any results

Great! Let us know.
I'm still using this method to get the batteries on a "real" 100%  charge.
I think I can get the 100% charging only with the 5V 1A charger but it is a slow (really slow) process

Once again: it doesn't work the way you think it works. You don't decide the charging current by plugging different chargers at the end of a charging cycle. Repeat your test by just using the 3A or 2A one untill a full charge, then disconnect it. Then, like in your previous experiments, after some time plug the power in again, but use the very same charger as before instead of the "lower A" one. You'll still see the LEDs dancing for a while.

esoriauy Posted at 2018-1-4 07:39
Great! Let us know.
I'm still using this method to get the batteries on a "real" 100%  charge.
I think I can get the 100% charging only with the 5V 1A charger but it is a slow (really slow) process

I normally have only 9 minutes of flying time but after using a standard charger like you replied  , I got 2 minutes extra using the standard charger  after using the DJI charger.

Will confirm  test results after i do  for another 3 flights .

If a batt has  a capacity of 1.7 amphrs, then the charge that takes  1 hour is correct which i a charging current of 1.7 amps.
Most lithium will take a 50% increase in that rate, so charging in less than an hour.
But at a price. Less of a charge and reduced batt life.
Charging at much less current takes longer but 'puts more in' so to speak, and prolongs batt life.
The idea that masses of electric  cars can be charged in 10 mins or so is terrifying with current technology.(pun intended)

thanks all for sharing your experiences and knowledge of charging batteries.  Wouldn't your charge count increase every time you change chargers to top up your battery?  This would make every charge go up by 3 instead of a count of 1.

Sparky_17 Posted at 2018-1-4 08:57
thanks all for sharing your experiences and knowledge of charging batteries.  Wouldn't your charge count increase every time you change chargers to top up your battery?  This would make every charge go up by 3 instead of a count of 1.

I'm not this deep in the Li-Ion chemistry intricacies so don't quote me on that, but I'm pretty sure I read somewhere that it's all about the current reversal. So, as long as you don't actually begin to draw current from the battery, pausing and then re-starting of the charging process shouldn't be counted as a new charge cycle.

Not that this matters much, though... ;)

Zbig Posted at 2018-1-4 09:42
I'm not this deep in the Li-Ion chemistry intricacies so don't quote me on that, but I'm pretty sure I read somewhere that it's all about the current reversal. So, as long as you don't actually begin to draw current from the battery, pausing and then re-starting of the charging process shouldn't be counted as a new charge cycle.

Not that this matters much, though... ;)

if the count is multiplied by the number of charge cycle then yes it does matter.  DJI only warranty the batteries to about 200 charges.  So this would mean that after 70 some charges it would exceed the 200 cycles.

Can anyone validate this?  Thanks

Sparky_17 Posted at 2018-1-4 10:29
if the count is multiplied by the number of charge cycle then yes it does matter.  DJI only warranty the batteries to about 200 charges.  So this would mean that after 70 some charges it would exceed the 200 cycles.

Can anyone validate this?  Thanks

I didn't mean shortening the battery cycle life doesn't matter. What I wanted to say is it doesn't matter in the context of this voodoo trick described here I still say it doesn't charge your battery more or increase your flight time and is a waste of time, until being proven otherwise. And no, flying around your room once with a battery charged normally and then second time, after applying the magical trick, doesn't prove anything. There is multitude of factors at play here, ranging from the  battery performance naturally changing in time (e.g. with temperature) to subconsciously flying in more calm and less straining (for Spark's propulsion system) manner just to prove yourself the point.

I don't know what threshold is used before a new charge cycle is counted, but it would also have to accomodate the batts' self discharge to storage voltage , which occurs after no usage of I think 10 days.

S.J Posted at 2018-1-4 07:49
I normally have only 9 minutes of flying time but after using a standard charger like you replied  , I got 2 minutes extra using the standard charger  after using the DJI charger.

Will confirm  test results after i do  for another 3 flights .

Really really awesome, I'm not crazy

Thanks for sharing your experience and have a nice (extended) flight!

Sparky_17 Posted at 2018-1-4 08:57
thanks all for sharing your experiences and knowledge of charging batteries.  Wouldn't your charge count increase every time you change chargers to top up your battery?  This would make every charge go up by 3 instead of a count of 1.

You could do a full charge with the 1A charger but it will take a much longer time.
Charging with 3A and then with 2A is just a shortcut
I don't know which is the "cycle" concept on the DJI batteries but we can test that with a charge cycles reader...

esoriauy Posted at 2018-1-4 20:03
You could do a full charge with the 1A charger but it will take a much longer time.
Charging with 3A and then with 2A is just a shortcut
I don't know which is the "cycle" concept on the DJI batteries but we can test that with a charge cycles reader...

Actually, the wall charger supplied by DJI is a QC3 unit and it will initially charge the Spark at 12V/1.5A (18W) this will be considerably faster than any 5V USB charger no matter what the amp rating is.

fansb181213c Posted at 2018-1-4 20:18
Actually, the wall charger supplied by DJI is a QC3 unit and it will initially charge the Spark at 12V/1.5A (18W) this will be considerably faster than any 5V USB charger no matter what the amp rating is.

The OEM wall charger received with my Spark is a 5V 3A.
The test was done with additional 5V 2A and 5V 1A chargers.
Now, waiting for the OEM DJI Hub Charger (3 bays) to check  the behaviour with it (I don't know the output specs)

This is nonsense. A 5 volt supply could produce 18 watts as long as it can produce c. 4 amps.

Bright Spark Posted at 2018-1-5 05:12
This is nonsense. A 5 volt supply could produce 18 watts as long as it can produce c. 4 amps.

It theory yes, but it would be impractical as neither the commonly available USB cables nor the micro USB connector are prepared for that kind of current. You'd waste too much power as heat due to resistive losses. It would be inefficient, unreliable, somewhat dangerous, even, and just a bad idea all around to push 4 amps of current through Micro USB. That's why it's not being done and that's why standards like Quick Charge offer voltages higher than 5V.

Guys, hear me out. There's so much confusion, half-truths, speculation and plain misconceptions in this and other threads regarding charging, it's not going anywhere and doesn't help anyone. Let me briefly explain the basic concepts behind charging batteries in modern devices. I'll talk about DJI Spark specifically but the information applies to broader range of electronics like smartphones, etc. Charging the DJI Spark or any modern, properly designed USB device is nothing like charging your car battery.

The thing is, you don't get to decide the battery charging current directly by connecting USB chargers with varying current capacities. Actually, the term "USB charger" is a bit of a misnomer and that doesn't help understanding things, either. USB charger is, in fact, just an AC-DC constant voltage power supply that is capable of providing electrical current up to the value printed on it, if needed and asked for. The actual charging circuitry is on the other end of a cable: in the Spark itself and its intelligent flight battery. The fact that you connect a 5V, 2A USB charger doesn't mean that the battery sees a constant current of 2A during the duration of the charge. It only assures that the charging circuitry inside the Spark and the battery has enough power available at its disposal to do its work properly. Again, it DOESN'T MEAN YOU'RE CHARGING YOUR BATTERY AT 2A. The charging process of a Li-Po battery is very critical and it can be dangerous if not done in a proper, strictly controlled manner. That's why neither you nor the USB "charger" (USB power supply) control the battery charging process. USB supply's only job is to provide a stable voltage at the current UP TO the value stated on its case, if and when the device being charged requests it. Towards the end of the Li-Po charging process, the charging current tapers off slowly as the battery fills up and when it diminishes to some specific, low value (like one tenth of the original charging current), the charging process concludes. This (the gradual decrease in charging current, down to almost zero) does and will happen regardless of the USB charger being used.

To put it another way: the mains socket on your wall is capable of providing, say 16A of current at 230V for the maximum theoretical power of 3860W. You can plug both a small LED desk lamp or a washing machine there and they will both work, right? Needless to say, the current being drawn by the washing machine is many times higher that the current being drawn by the LED lamp, right? How do you think does that work? How's it possible that the desk lamp doesn't blow up to smithereens once plugged to a "power supply" (the socket in your wall) capable of powering a washing machine? Do you think it is the mains socket that "decides" the current that will flow to the device? Or perhaps the device being plugged in it governs that?

The USB charger juggling described by the OP is a pointless exercise and a waste of time but of course it's your time to waste.

Zbig
I was responding to the post 5 before this that states no way could any 5 volt charger compete with 18 watts.
4 amps is bordering on impracticable for a micro usb but not my point. BTW the supplied charger is rated at 5v 3 amp -not 4 amp I agree but still 15 wats.

Bright Spark Posted at 2018-1-5 07:19
Zbig
I was responding to the post 5 before this that states no way could any 5 volt charger compete with 18 watts.
4 amps is bordering on impracticable for a micro usb but not my point. BTW the supplied charger is rated at 5v 3 amp -not 4 amp I agree but still 15 wats.

Fair enough, no worries. Having a Fly More Combo, I don't have the original white DJI USB charger so didn't know it's a 3A one. My 2A@5V figure is based on the actual measurements I done while charging my Spark (using even more capable USB supply).

It's quite interesting all this battery stuff!
The  battery contacts themselves are not that substantial, to put out say 6 or more amps.Cells could be tapped separately though.
Puts me well off an electric car!

Bright Spark Posted at 2018-1-5 07:55
It's quite interesting all this battery stuff!
The  battery contacts themselves are not that substantial, to put out say 6 or more amps.Cells could be tapped separately though.
Puts me well off an electric car!

Interesting indeed. And the those ~6 Amps would be an average current for the whole flight with possible peaks (like Spark shooting off quickly or negotiating the wind) much, much higher! The battery contacts are doubled, i.e. there's two of them for (+) and another two for (-). The separate cell taps are used for charge balancing internally but the Spark sees the cumulative voltage (3 cells in series) only. While I agree the Spark battery's contacts don't look like much, they're still bigger than the tiny "fingers" inside microUSB plug. And they're both stiffer and grasp the contact from both sides, too, unlike those in microUSB.

Regarding the electric cars, in the Tesla for instance, after you plug the charger in, the system first measures the contact resistance down to milliohms and only if it's deemed low enough the charging commences. Otherwise you'd run the risk of the plug and socket assembly virtually disintegrating in an instant, considering the currents involved.

There's some serious  currents there I agree.
Spark's contacts are high quality as you say, but I inspect them often in case of accidental  misalignment, likewise the locks. If you pull to release without supporting battery, I can see those tiny lugs rounding over.
People are promising all manner of virtually instant car charging, but here(UK) our grid can't cope already!

Bright Spark Posted at 2018-1-5 08:48
There's some serious  currents there I agree.
Spark's contacts are high quality as you say, but I inspect them often in case of accidental  misalignment, likewise the locks. If you pull to release without supporting battery, I can see those tiny lugs rounding over.
People are promising all manner of virtually instant car charging, but here(UK) our grid can't cope already!

Like you, I don't operate the Spark's battery release locks without pushing down on the battery at the same time. The picture of the lugs clinging on the Spark's locking protrusions by the last thenth of a millimeter, carrying all the battery holding force until the battery snaps off, scares me.

I agree regarding the electric vehicles. Fortunately, there's hybrid: the current best of the both words, if you ask me. I personally think there'll be a period when most of us will be driving hybrids in one form of another, for much longer than most tend to think, before we'll switch to pure electric entirely.

That's how I see it.and
For city cars get weight down as much as possible.
For me spark is remarkable in this.  In my electric aircraft pursuits, 60 amps
is small fry. Spark uses say 75 watts and is packed with goodies.

Bright Spark Posted at 2018-1-5 05:12
This is nonsense. A 5 volt supply could produce 18 watts as long as it can produce c. 4 amps.

It could but it wouldn't.....hence the QC3 specification.....so, it's not nonsense