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Preventing controller from charging phone

As someone suggested, I connected my phone to the large usb port in the back, and connected the upper port to a powerbank. That way I managed to keep the controller with a good charge through 9 plus batteries in the drone. The phone battery also kept high (had to connect it to another powerbank between on breaks).

Cumbersome but worked well I might make some kind of tray to hold all of that together, something breathable would be best as everything gets hot.
 
a resistor on the positive wire would help perhaps, but, it is too much effort for such a thing.
That was tried too, attempting to limit current to around 10mA. That didn't work in the field. Minimum current may be around 100mA at least as a probe current from the Android.
 
That't probably a resistor as suggested before. It would be interesting to know.
Yeah, the circuit lets through some curren, so the phone sees the connection, but it's way less than full on charging. To put it in numbers, the Mavic controller will charge at 500-800mA but this thing only lets through 1-30mA depending on the phone you use. So it's a significant difference
 
Yeah, the circuit lets through some curren, so the phone sees the connection, but it's way less than full on charging. To put it in numbers, the Mavic controller will charge at 500-800mA but this thing only lets through 1-30mA depending on the phone you use. So it's a significant difference
Tks for the details. Do you have any information about the actual circuit? Although very inexpensive it's out of reach for some one in Brazil like myself. I've seen suggestion of using a resistor in one the the lines, which I suppose is what this dongle does. It seems from the video that it's covered by a simple heat shrink that would allow us to see the actual circuit.
 
I have been looking hi and lo for this. I'm using a Galaxy S9. There is no way to do it. BTW, I'm wondering why DJI leaves the blind leading the blind? Why in these "forums" are users left to solving problems the designers could answer instantly?
 
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I have been looking hi and lo for this. I'm using a Galaxy S9. There is no way to do it. BTW, I'm wondering why DJI leaves the blind leading the blind? Why in these "forums" are users left to solving problems the designers could answer instantly?

Yes, I am in the same boat as you. I am looking at either getting a tablet or trying the charge blocker... or even possibly trying accessing the DATA tab and making sure I turn it on and off with every use. The S9 is a great phone... but I wish DJI would offer support to help me connect it.
 
Yes, I am in the same boat as you. I am looking at either getting a tablet or trying the charge blocker... or even possibly trying accessing the DATA tab and making sure I turn it on and off with every use. The S9 is a great phone... but I wish DJI would offer support to help me connect it.
i simply switched to iphone xr and are very happy with it. it is considerably better any other android phones, and, in my opinion, is overall better than other iphones as well.
 
I have just cut into a USB cable to get access to the +5V and ground wires. The cable is the normal big USB plug to a micro USB B plug, i.e. the 'normal type Android phone data and charge cable.
After cutting the +5V and ground wires I was able to add a variable-resistor/decade-box in the +5V wire and add a digital multi meter (DMM) to measure the current flowing through either the +5V wire or the ground wire.
I wasn't prepared to risk using either the drone's controller or my 'good' phone as Guinea Pigs so connected the cable between a powered USB hub ( connected to my computer) and an old Samsung smart phone.
With the resistance set to 0 the current in the +5V wire is around 450mA, and the phone is seen by the computer.
Once the resistance is increased to 3 or 4 ohms the analogue display of the DMM goes haywire and indicates a rapidly varying current, the value indicated on the DMM's digital display drops significantly but is unstable. The phone display switches between showing charging and showing not charging, the computer was still able to see the phone.
I did flick through a few higher resistances and the DMM's displays did not settle down.
As I didn't want to needlessly risk damaging the phone I returned the resistance to 0.
Disconnecting the ground wire did not disconnect the phone or from memory reduce the current in the +5V wire.
It seems to me that what ever goes on in these cables and connections is not simple................ho hum
 
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Under which Menu - camera, control because I can not see it either? I am using Samsung A8 android.
You won't see it because the option is only available for iOS.

Android never provided an API for apps to use to turn off charging. You can do it if your phone is rooted, or if the mfr provided access, but DJI can't rely on that.
Apple on the other hand provided a means for apps to control charging.

Because of USB electrical standards, the remote must provide at least 500mA power and most USB circuits want to see power in order to acknowledge use of data.
 
I have just cut into a USB cable to get access to the +5V and ground wires. The cable is the normal big USB plug to a micro USB B plug, i.e. the 'normal type Android phone data and charge cable.
After cutting the +5V and ground wires I was able to add a variable-resistor/decade-box in the +5V wire and add a digital multi meter (DMM) to measure the current flowing through either the +5V wire or the ground wire.
I wasn't prepared to risk using either the drone's controller or my 'good' phone as Guinea Pigs so connected the cable between a powered USB hub ( connected to my computer) and an old Samsung smart phone.
With the resistance set to 0 the current in the +5V wire is around 450mA, and the phone is seen by the computer.
Once the resistance is increased to 3 or 4 ohms the analogue display of the DMM goes haywire and indicates a rapidly varying current, the value indicated on the DMM's digital display drops significantly but is unstable. The phone display switches between showing charging and showing not charging, the computer was still able to see the phone.
I did flick through a few higher resistances and the DMM's displays did not settle down.
As I didn't want to needlessly risk damaging the phone I returned the resistance to 0.
Disconnecting the ground wire did not disconnect the phone or from memory reduce the current in the +5V wire.
It seems to me that what ever goes on in these cables and connections is not simple................ho hum
That makes sense. At first there's low load from the device so there's minimal voltage drop across the resistor.. The device sees 5v, turns on charging. Now there's a 500mA load, which causes a significant enough voltage drop across the resistor. Device sees voltage loss so it stops charging. Voltage is back up so device starts charging.

Similar action seen with the M2 car charger when engine not running and battery voltage just under 12v. Charger sees power, battery starts charging after a few seconds. It then pulls 6A which causes sufficient voltage drop across car wiring that charger stops due to low voltage cutoff. With charging stopped, voltage is back up. Charger turns on. Battery starts charging.

There may be a balance where voltage is just low enough to not trigger charging but not so low that data is cut off. May need an active current limiter circuit.
 
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