Charging the Mavic's RC using a mobile power bank: not recommended

[daisy-girl]

"3. Can I charge the Mavic's remote controller using a mobile power bank?
"It is not recommended to charge the remote controller with a mobile power bank. This may damage the coulometer. Battery level readings for the remote controller may become incorrect, and the battery consumption speed may become greater than the charging speed."

Right-click the link then "Open Link in New Tab"

Source: DJI - The World Leader in Camera Drones/Quadcopters for Aerial Photography

So we must use only household Alternating Current to charge our Remote Controls?

 

[sar104]

I'd have to classify that instruction between marginal and gibberish. They are probably trying to cover themselves against damage due to poor power sources, but the controller is charged using a standard USB protocol; 5 V and around 1.5 A. It shouldn't matter what the source is as long as it is compatible.

As for the coulometer, I'm not sure what to say...

 

[daisy-girl]

I'd have to classify that instruction between marginal and gibberish. They are probably trying to cover themselves against damage due to poor power sources

That makes sense

but the controller is charged using a standard USB protocol; 5 V and around 1.5 A. It shouldn't matter what the source is as long as it is compatible.

That makes sense, too, which I'm glad to know, as I really don't want to discontinue my habit of using a Power Bank (PB) to keep the charge on my RC between 30-80% while flying -- plug the PB into the RC when the RC drops to 30% on its own, and unplug the PB when the RC gets to about 80%

As for the coulometer, I'm not sure what to say...

Thanks for the reply.

 

[rangemaster728]

"3. Can I charge the Mavic's remote controller using a mobile power bank?
"It is not recommended to charge the remote controller with a mobile power bank. This may damage the coulometer. Battery level readings for the remote controller may become incorrect, and the battery consumption speed may become greater than the charging speed."

Right-click the link then "Open Link in New Tab"

Source: DJI - The World Leader in Camera Drones/Quadcopters for Aerial Photography

So we must use only household Alternating Current to charge our Remote Controls?

Definition of coulometer:
An instrument of chemical analysis that determines the amount of a substance released in electrolysis by measurement of the quantity of electricity used.

1 coulomb is the quantity of electrons necessary for 1A of current flow for 1 second; the statement regarding charging the remote is fancy verbiage for “you could potentially damage the electronics in the battery/remote that measures charge”.

You have a huge version of this on your house, called a KWHr meter the power company uses to determine how much energy you consumed.

Apparently the battery in the remote is not as ‘smart’ as the flight batteries for the aircraft...if you use any decent smart power bank that regulates charge rate -and a good cable - you’d likely be OK.

 

[Mavflyer]

"3. Can I charge the Mavic's remote controller using a mobile power bank?
"It is not recommended to charge the remote controller with a mobile power bank. This may damage the coulometer. Battery level readings for the remote controller may become incorrect, and the battery consumption speed may become greater than the charging speed."

Right-click the link then "Open Link in New Tab"

Source: DJI - The World Leader in Camera Drones/Quadcopters for Aerial Photography

So we must use only household Alternating Current to charge our Remote Controls?

The way it's worded sounds like you aren't supposed to charge it while you are actively using it to fly.

 

[sar104]

Definition of coulometer:
An instrument of chemical analysis that determines the amount of a substance released in electrolysis by measurement of the quantity of electricity used.

1 coulomb is the quantity of electrons necessary for 1A of current flow for 1 second; the statement regarding charging the remote is fancy verbiage for “you could potentially damage the electronics in the battery/remote that measures charge”.

You have a huge version of this on your house, called a KWHr meter the power company uses to determine how much energy you consumed.

Apparently the battery in the remote is not as ‘smart’ as the flight batteries for the aircraft...if you use any decent smart power bank that regulates charge rate -and a good cable - you’d likely be OK.

Agreed - it's going to work just fine. But note that a Coulometer is not the same as a power/energy meter - it's specific to measuring electrolysis.

 

[KiterTodd]

Definition of coulometer:
An instrument of chemical analysis that determines the amount of a substance released in electrolysis by measurement of the quantity of electricity used.
...Apparently the battery in the remote is not as ‘smart’ as the flight batteries for the aircraft...if you use any decent smart power bank that regulates charge rate -and a good cable - you’d likely be OK.

That's just the thing, I think most people use cheap power banks. They are dime a dozen these days and there are many cheap versions out there. I don't think most have any charge regulator other than whatever powers the LED. They're just a battery at a slightly higher voltage than what you are charging, and they drain until the potential difference between the two is zero.

It sounds like the risk is that the remote will lose ability to learn power levels and charging status. I suspect after a period of time, it will stabilize, but maybe for a few cycles after you use a cheap battery stick, things won't be as accurate. You're better off using the USB adapter that DJI sells (and provides with the FlyMore combo) and just charging the remote from a DJI Flight battery.

 

[sar104]

That's just the thing, I think most people use cheap power banks. They are dime a dozen these days and there are many cheap versions out there. I don't think most have any charge regulator other than whatever powers the LED. They're just a battery at a slightly higher voltage than what you are charging, and they drain until the potential difference between the two is zero.

It sounds like the risk is that the remote will lose ability to learn power levels and charging status. I suspect after a period of time, it will stabilize, but maybe for a few cycles after you use a cheap battery stick, things won't be as accurate. You're better off using the USB adapter that DJI sells (and provides with the FlyMore combo) and just charging the remote from a DJI Flight battery.

Provided that the power source is USB compliant there should not be a problem, because the charging current is regulated by the charging circuit in the device itself. Now, if people are somehow interfacing the USB charging cable with random external batteries at uncontrolled voltages, then that's a quite different problem.

 

[caspian]

if apparently you can't use a power bank then presumably you can't use any USB port other than the one on the DJI charger, because there's no way to "guarantee" any of them meet the power standards the RC requires.

but somehow, magically the USB adapter for the main aircraft battery does?

sounds like arse covering to me.

 

[daisy-girl]

As for the coulometer, I'm not sure what to say...

The following quotation is from http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

"Estimating SoC [State of Charge] by reading the voltage of a charging battery is impractical; measuring the open circuit voltage (OCV) after the battery has rested for a few hours is a better indicator. As with all batteries, temperature affects the OCV, so does the active material of Li-ion. SoC of smartphones, laptops and other devices is estimated by coulomb counting. (See BU-903: How to Measure State-of-charge.)

"A portable device should be turned off during charge. This allows the battery to reach the set voltage threshold and current saturation point unhindered."

In light of this information, from now on I'm going to use a Power Bank out in the field only in those rare instances that I still need to fly but the remaining SoC of my RC is insufficient to continue flying safely.

 

[nikkolaa]

The way it's worded sounds like you aren't supposed to charge it while you are actively using it to fly.

I guess it's the real recommendation here,.

Lipo batteries usually do not like so much being discharged and charged at the same time. At least when keeping the discharge rate and current stable is a requirement.

 

[sar104]

The following quotation is from http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

"Estimating SoC [State of Charge] by reading the voltage of a charging battery is impractical; measuring the open circuit voltage (OCV) after the battery has rested for a few hours is a better indicator. As with all batteries, temperature affects the OCV, so does the active material of Li-ion. SoC of smartphones, laptops and other devices is estimated by coulomb counting. (See BU-903: How to Measure State-of-charge.)

"A portable device should be turned off during charge. This allows the battery to reach the set voltage threshold and current saturation point unhindered."

In light of this information, from now on I'm going to use a Power Bank out in the field only in those rare instances that I still need to fly but the remaining SoC of my RC is insufficient to continue flying safely.

My comment, or lack of it, on the Coulometer reference, was mostly because they have misused the term - probably a translation issue more than anything.

The coulomb is the SI unit of charge, equivalent to approximately 6 x 10^18 electrons. It's the quantity of charge flowing per second in a conductor carrying 1 amp of current. Charging a battery involves moving charge, and so it is not an irrelevant parameter, but it's not a defining one either since stored energy depends on both charge and voltage. More specifically, "coulometer" is a rather archaic term for a device to measure the mass moved from anode to cathode during an electrolytic process.

 

[s2seyecle]

My comment, or lack of it, on the Coulometer reference, was mostly because they have misused the term - probably a translation issue more than anything.

The coulomb is the SI unit of charge, equivalent to approximately 6 x 10^18 electrons. It's the quantity of charge flowing per second in a conductor carrying 1 amp of current. Charging a battery involves moving charge, and so it is not an irrelevant parameter, but it's not a defining one either since stored energy depends on both charge and voltage. More specifically, "coulometer" is a rather archaic term for a device to measure the mass moved from anode to cathode during an electrolytic process.

Phew... I gotta tell you guys.... all this science talk is getting me really aroused ;-)

 

[Tinmania]

That's just the thing, I think most people use cheap power banks. They are dime a dozen these days and there are many cheap versions out there. I don't think most have any charge regulator other than whatever powers the LED. They're just a battery at a slightly higher voltage than what you are charging, and they drain until the potential difference between the two is zero.

It sounds like the risk is that the remote will lose ability to learn power levels and charging status. I suspect after a period of time, it will stabilize, but maybe for a few cycles after you use a cheap battery stick, things won't be as accurate. You're better off using the USB adapter that DJI sells (and provides with the FlyMore combo) and just charging the remote from a DJI Flight battery.

Nah.

I could see if we were talking about a sensitive A/C device and trying to use a cheap modified sine wave inverter to power it. But we are talking about a simple 5V D/C feed, whether it comes from a battery or a transformer doesn't really matter. The only "regulator" needed is to provide 5V--which USB chargers or battery banks do. The battery and battery charger itself, which in this case is builtin to the R/C, are what determines what amperage to pull.



Mike

 

[Kilrah]

So we must use only household Alternating Current to charge our Remote Controls?

No, just poorly worded. What's not recommended is charging while using.

 

[sar104]

No, just poorly worded. What's not recommended is charging while using.

I guess you could try to charge while in use if flying with just the controller and no mobile device.

 

[Tinmania]

I guess you could try to charge while in use if flying with just the controller and no mobile device.

Most modern mobile devices can do that, assuming adequate current.

For example, most any iPhone, including the first one, can do that. But the battery is not actually being charged and used for power (discharged) simultaneously. Instead power from the connected power supply is used to power the device itself. Surplus power is used to charge the battery. If the connected power supply cannot supply enough current to even power the device, the device will automatically switch to battery power and battery power only. You can see this with, for example, iPhones, that vacillate between charging and not charging when turned on and connected to a power supply that can't supply enough current to power it sufficiently (e.g., some automobile USB adapters, the USB port on the Mavic RC, etc.).

I would be surprised if the Mavic RC doesn't have similar behavior.


Mike

 

[sar104]

Most modern mobile devices can do that, assuming adequate current.

For example, most any iPhone, including the first one, can do that. But the battery is not actually being charged and used for power (discharged) simultaneously. Instead power from the connected power supply is used to power the device itself. Surplus power is used to charge the battery. If the connected power supply cannot supply enough current to even power the device, the device will automatically switch to battery power and battery power only. You can see this with, for example, iPhones, that vacillate between charging and not charging when turned on and connected to a power supply that can't supply enough current to power it sufficiently (e.g., some automobile USB adapters, the USB port on the Mavic RC, etc.).

I would be surprised if the Mavic RC doesn't have similar behavior.


Mike

Agreed - but that was not what I was getting at. If you plug a cable into the charging port, whether it is connected to anything or not as far as I can tell, then the full-sized USB port doesn't work for data. So I cannot see how one could have a charger and a mobile device connected simultaneously.

 

[Tinmania]

Agreed - but that was not what I was getting at. If you plug a cable into the charging port, whether it is connected to anything or not as far as I can tell, then the full-sized USB port doesn't work for data. So I cannot see how one could have a charger and a mobile device connected simultaneously.

Sorry, perhaps I was not clear: When I referred to "most modern mobile devices" I didn't mean when connected to a Mavic RC. I just meant that you can certainly use them while they are plugged into a power source.

Your suggestion to try flying with just the RC and no mobile device, but with the RC connected to power, was what I was referring to. Most any modern device can do that without issue. My take is that I doubt the MP RC is any different.

Without question the comment, presumably from dji, "battery consumption speed may become greater than the charging speed" is on its surface, bogus as you can't charge and draw from the battery at the same time. But it could be a language issue, CYA issue, or anything in between.



Mike

 

[sar104]

Sorry, perhaps I was not clear: When I referred to "most modern mobile devices" I didn't mean when connected to a Mavic RC. I just meant that you can certainly use them while they are plugged into a power source.

Your suggestion to try flying with just the RC and no mobile device, but with the RC connected to power, was what I was referring to. Most any modern device can do that without issue. My take is that I doubt the MP RC is any different.

Without question the comment, presumably from dji, "battery consumption speed may become greater than the charging speed" is on its surface, bogus as you can't charge and draw from the battery at the same time. But it could be a language issue, CYA issue, or anything in between.



Mike

Ah - right. I agree.