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

[daisy-girl]

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.

If a data device is plugged into the left-side RC port, then it's true that no data can be obtained from the lower USB port.

But if I plug my Power Bank into the left-sided RC port and connect my iPad Mini 4 to the RC via the lower USB port, I've got data while simultaneously charging the RC.

According to Rick of Drone Valley, it is perfectly okay to charge one's RC with a Power Bank in the field this way -- BUT he does not clarify whether he means while flying or between flights.

 

[sar104]

If a data device is plugged into the left-side RC port, then it's true that no data can be obtained from the lower USB port.

But if I plug my Power Bank into the left-sided RC port and connect my iPad Mini 4 to the RC via the lower USB port, I've got data while simultaneously charging the RC.

According to Rick of Drone Valley, it is perfectly okay to charge one's RC with a Power Bank in the field this way -- BUT he does not clarify whether he means while flying or between flights.

Yes - in another thread @Kilrah pointed out that it is only OTG cables connected to the side port that disable the USB A port. Charging should work. And charging while flying really should not be a problem unless DJI have done something very strange with their charging circuitry.

 

[Boss_Vyc]

Hi

This is an home made charger. Only an simple step up/down converter board (7$) and some display voltage. Is very stable with voltage and ampers. He can provide with an extra radiator and an laptop fan cooler up to 12 amps. So i can charge 3 batteries in the same time very fast. I use for outdoor 3 flex batteries and with 1 (18 volts and 4 amps battery) i can charge 2 mavic pro batterys. Very good and easy to build.

 

[jag32266]

All very interesting and thx for all this good information. I've acquired enough batteries (5) where this is an actual concern as the controller runs out of energy before the batts are drained
What I was considering for the just-in-case scenario is a larger car jumper style battery pack which also has a usb connection. I thought in a pinch I could use the usb to charge the controller during the times when there isn't an electric location to be had for proper charging. I would never consider attempting to charge while flying- that to me is an extreme and better understood after reading here.

Curious though and something I've wondered about as posted by daisy girl- ""A portable device should be turned off during charge. This allows the battery to reach the set voltage threshold and current saturation point unhindered."

I always do this and have never ceased to wonder as to WHY when plugged in to charge the first thing that happens is what- it turns itself back on! I mean WTH. Seems counter intuitive to me. Look froward to more replies.

Btw, I have that many batteries as I have an interest in helping SAR issues (helped out b4 for the county) and the EMS.

 

[Boss_Vyc]

You must provide for charging the drone battery 13 volts and maximum 6amps. The rest for limit the charge is made it from PCB (inside the drone battery). Have allot protection there and he can charge correctly and ballanced each cell.
Also in the future i will add inside the charging box 2 stabilizer 5 volts to charge the rc.

 

[Eraser339]

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...

Coulometry - Wikipedia

 

[Eraser339]

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.

What about using the smart battery and the USB adapter as the energy source. Is that an oxymoron.

 

[sar104]

Coulometry - Wikipedia

Yes - thank you - I know what it is. What I don't know is what to say about it appearing so far out of context. The RC definitely does not have a coulometer.

 

[daisy-girl]

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

Update 2018 0414@1510

Because I've been using a Power Bank for weeks that has kept the RC always at 100%. I decided to let it discharge to 30% while flying.

When I got home, I shut it down and then I tried 3 different AC chargers, and for each one the RC would charge a few percent and then stop charging. I interpreted this to mean that the RC's battery was not digesting well the sources of electrons.

So I got out the 50W charger that came with the RC and AC.

The RC reacted by steadily climbing toward 100%. Because I knew I would be flying again in less than 24 hours, I allowed it to go all the way to 100% per the manual.

Otherwise, I would have unplugged it at about 65% and topped it off the next time I was going to fly, as 65% is what DJI recommends when its batteries are not going to be used for a while.

I'm going to stick with the 50W charger from now on as the RC seems to prefer it.

 

[sar104]

Update 2018 0414@1510

Because I've been using a Power Bank for weeks that has kept the RC always at 100%. I decided to let it discharge to 30% while flying.

When I got home, I shut it down and then I tried 3 different AC chargers, and for each one the RC would charge a few percent and then stop charging. I interpreted this to mean that the RC's battery was not digesting well the sources of electrons.

So I got out the 50W charger that came with the RC and AC.

The RC reacted by steadily climbing toward 100%. Because I knew I would be flying again in less than 24 hours, I allowed it to go all the way to 100% per the manual.

Otherwise, I would have unplugged it at about 65% and topped it off the next time I was going to fly, as 65% is what DJI recommends when its batteries are not going to be used for a while.

I'm going to stick with the 50W charger from now on as the RC seems to prefer it.

I made a few measurements of the charging characteristics. On a dedicated charger the RC pulls around 1.4 - 1.5 A at 5 V. That goes up to around 1.6 A if the RC is powered up. I tried it with a a RAVPower RP-PB26 with approximately the same. I also tried a 1 A iPhone charger, which actually supplied 1.2 A, and it seemed to charge fine with that too.

 

[daisy-girl]

I made a few measurements of the charging characteristics. On a dedicated charger the RC pulls around 1.4 - 1.5 A at 5 V. That goes up to around 1.6 A if the RC is powered up. I tried it with a a RAVPower RP-PB26 with approximately the same. I also tried a 1 A iPhone charger, which actually supplied 1.2 A, and it seemed to charge fine with that too.

In the past -- before I'd kept it at 100% for a prolonged period of time with a Power Bank -- I too was able to charge the RC with a number of different AC chargers.

Like others have written, my conclusion is that charging while flying is not recommended. So if I need to use the Power Bank in the field because I'm not done flying, I'm going to first shut the RC down.

 

[Eraser339]

Yes - thank you - I know what it is. What I don't know is what to say about it appearing so far out of context. The RC definitely does not have a coulometer.

Yes. It looks like a generalisation from the smart batteries, which MAY use them. See:-

The IBC provides accurate and easy testing of heat output from charging and discharging a single battery.

Heat occurring during the charging and discharging of batteries is largely due to their internal impedance. Characterisation of this heat at different operating temperatures is vital for efficient thermal management of cells in packs or modules.

Isothermal calorimeters have higher sensitivity that adiabatic calorimeters. Their temperature range is limited and they are not appropriate for safety abuse testing when battery disintegration or high temperatures may result.

Isothermal Battery Calorimeter

 

[Eraser339]

Yes - thank you - I know what it is. What I don't know is what to say about it appearing so far out of context. The RC definitely does not have a coulometer.

Bear in mind that some battery packs have a fast charge(2C) as well as normal(1C). I have a lithium battery pack that can take 30C continuous or 60C Max burst. That must produce some heat.

 

[sar104]

Yes. It looks like a generalisation from the smart batteries, which MAY use them. See:-

The IBC provides accurate and easy testing of heat output from charging and discharging a single battery.

Heat occurring during the charging and discharging of batteries is largely due to their internal impedance. Characterisation of this heat at different operating temperatures is vital for efficient thermal management of cells in packs or modules.

Isothermal calorimeters have higher sensitivity that adiabatic calorimeters. Their temperature range is limited and they are not appropriate for safety abuse testing when battery disintegration or high temperatures may result.

Isothermal Battery Calorimeter

I think my original comment keeps getting taken out of context. Yes - there is all kinds of interesting chemistry in these lithium batteries, but no, none of them have coulometers.

 

[silverdragon]

I used the Romoss 10000 PC on the mavic pro rc while it was in use flying the aircraft. I hooked it up to the rc when it was at 80%, flew the aircraft for 20 minutes and it increased to 83% when i was done flying. So it increased 3% on the rc.

 

[Aloha_MavicPro]

If they remote designer design a remote controller that allow us to replace exhausted battery from the remote like we replaced aircraft battery will be nice, we can buy and carry extra battery packs for the remote like we have extra flight pack.Why don't they think of that.

 

[Mossiback]

What about using the smart battery and the USB adapter as the energy source. Is that an oxymoron.

I did it and it worked fine. The Mavic battery had 1 led showing but was enough to recover the RC from it's low battery warning.

 

[Tinmania]

I'm going to stick with the 50W charger from now on as the RC seems to prefer it.

FYI the charger will only supply 10W via USB to charge the RC (5V @ 2A max). Any 2A or higher USB charger will work the same.



Mike