Mavic Mini: Ratio # flight batteries vs one charge Remote Control?

[kerrylaw7307]

Yes, the issue is that Androids do not provide a means for apps to disable charging, and USB standards state that a USB host, RC in this case, needs to provide at least 500mA to a target device, the phone/tablet in this case. So, the Android goes into slow charge when connected to the RC, drawing up to 500mA from the RC.

In other Mavic models, you could connect the phone/tablet to a USB A port on the bottom, and a power bank on the side port in the same way you'd be charging the RC.

For the MIni though, there's only one USB port, the one on the side. It can only be in one of two modes:
A/OTG mode: acts as if it is a PC from the phone's perspective, providing power to the connected device.
B mode: Accepts power for charging, also accepts connection as a device, usually with a PC for transferring files from the SD card, and communication with Assistant for firmware updates.

So how about opening the controller, and placing a jack in parallel with its battery? Then "plug in" an external battery / power pack?

 

[kerrylaw7307]

It's a limitation of the Android API that apps have to use to access Android control, and USB minimum specs that an A mode device (OTG mode, RC in this case) must provide a B mode device (Android in this case) with 500mA. Many Androids will ignore the USB if no power is provided to it.
Some manufacturers have included full charge control. They can because they have root access for their built-in apps and settings. User apps do not.

Some experimenting was done to passively limit current by using a resistor. So far that's been unreliable.

So how about opening the controller, and placing a jack in parallel with its battery? Then "plug in" an external battery / power pack? If this now gives the RC 2x or more, the battery capacity, do I care now if it tries to charge my phone? I have 2x what I had before!

 

[DanMan32]

Direct parallel connection of li-ion batteries or battery to constant power source isn't the best idea. That's why we have charge circuits.

 

[kerrylaw7307]

Direct parallel connection of li-ion batteries or battery to constant power source isn't the best idea. That's why we have charge circuits.

I didnt say connect a constant power source. I suggested connecting another battery in parallel with the one in the RC. This will mearly double or triple the available capacity to the RC. NO change in voltage, just more mah. Li-ion batteries can be connected in parallel with no issues. Would this not solve the "RC is charging the phone/table, and running down the RC" issue?? Heck, disconnect the internal battery completely and connect a large 5000/10000mah Li-ion pack externally. Should fix the issue, right?

 

[DanMan32]

Actually connecting LiIon in parallel does have its issues, main one being that if there's not an exact match, one takes over the other. That's why industry switched to series. If you use diodes (or FETs configured as diodes for lower voltage drop) to prevent backfeed, that would be OK, or replace one with the other.
If replacing, there's a chance there's a BMS that will detect 0v from battery and shut down like a fuse. This is because a LiPo allowed to drain below safe voltage should never be recharged.

 

[kerrylaw7307]

I kinda understand. SO.... what is CareyL doing here? Seems like he has a way of connecting controller to phone and also to external battery, via the extra USB plug. Does he have a solution here?

Be careful post#38

 

[penuela.lance]

Hi im Lance From Ph. My controller only runs 15mins less in full charge. Im using a Nokia 6.1. i dont know why if its the controller whos faulty or i got a bad remote. Please help. Thank you. Its sad that i cant even deplete a one whole battery of Mavic mini.

It missreads the battery. When i turn On again the remote it show 3 bars again.

 

[DanMan32]

Hi im Lance From Ph. My controller only runs 15mins less in full charge. Im using a Nokia 6.1. i dont know why if its the controller whos faulty or i got a bad remote. Please help. Thank you. Its sad that i cant even deplete a one whole battery of Mavic mini.

It missreads the battery. When i turn On again the remote it show 3 bars again.

That sounds like a defective remote, maybe defective cable. You should get at least 2 full flights out of it.
Can you try a different phone just to be sure?

 

[DanMan32]

I kinda understand. SO.... what is CareyL doing here? Seems like he has a way of connecting controller to phone and also to external battery, via the extra USB plug. Does he have a solution here?

Be careful post#38

I'm not comfortable with his setup. He is forcing charge upstream back into the RC. When in that mode, the RC is wanting to send power out. If there were no active power components between the RC USB port and its battery, that would be fine. But clearly that's not the case.

Even if it seemed safe, it certainly is cumbersome.

 

[CareyL]

My real world experience using a power bank and OTG cable is that my phone stays at 100% and my controller only depletes to about 50% after 3 batteries worth of Mini flight. Danman's conjecture is a curious set of biases based on no particular evidence from what I can see.

Current seems to be demand driven and if there is no demand, (since the phone is receiving maximum charge from the power bank), the MC only draw is its own. I also have hot glued a micro cable to the MC to avoid any plug/unplug damage to the MC side when changing from charging to data.

One note I should have mentioned is that you need to establish the data connection before attaching the power bank.

I'm not comfortable with his setup. He is forcing charge upstream back into the RC. When in that mode, the RC is wanting to send power out. If there were no active power components between the RC USB port and its battery, that would be fine. But clearly that's not the case.

Even if it seemed safe, it certainly is cumbersome.

Regarding cumbersome: I guess it depends on your imagination. I velcro the power bank to the back of my phone and MC. It balances well.

 

[DanMan32]

There are two power and data modes with the side micro USB port:
A mode where it provides power and acts like a host so you can connect your phone. This is done with an OTG cable that grounds pin 5. You have to be in A mode for the RC and phone to communicate. In this mode, the RC is expecting to push power, not receive it.

B mode is what a phone normally would be in, and the mode your RC goes into when you don't use an OTG cable but rather a normal cable to charge your RC. This is also the mode you would update the firmware for your RC when connected to your PC. Your PC provides power to the RC in this case.

So, when you connect a power source to a USB port in A or OTG mode, it's like connecting two power supplies together against each other. The RC is a power source. The power bank is a power source. Bank is pushing power in excess of what the RC is pushing. Not a good way to go, even if you happen to be getting away with it. You do take the risk of damaging the RC's power circuits to the USB port.

In other Mavics with the full size A port on the bottom, when you use this port to connect to your phone, you are free to use the side port as B mode to charge your RC.
Not so with the Mini as it has only one port. A USB port can't operate in A mode for data and B mode for power at the same time. It's all A or all B.

If you do end up damaging the power circuit to the USB, you will either be unable to charge your RC, or your phone won't connect because it no longer sees any power on the USB bus. Maybe both.

It's your system, your risk. I don't recommend anyone else taking the risk.

 

[Deleted member 109934]

I received my Mavic Mini fly more Combo just this week. I made just one flight and was quite satisfied with the flying time. However the speed how the remote Control discharged concerned me somewhat. Does anybody have already some experience how many flight batteries can be flown with one charge of the remote Control?
Thanks for input

With iPhone I went through 8 batteries and remote still had 2 LEDs blinking in 3C temperature.

 

[DanMan32]

With iPhone I went through 8 batteries and remote still had 2 LEDs blinking in 3C temperature.

IPhones have API to allow applications to turn off charging on the iPhone and the Go/Fly app does just that. Androids do not natively have this control in the API. Therefore the discussion is not relevant to iPhones, only with Androids.

 

[kerrylaw7307]

There are two power and data modes with the side micro USB port:
A mode where it provides power and acts like a host so you can connect your phone. This is done with an OTG cable that grounds pin 5. You have to be in A mode for the RC and phone to communicate. In this mode, the RC is expecting to push power, not receive it.

B mode is what a phone normally would be in, and the mode your RC goes into when you don't use an OTG cable but rather a normal cable to charge your RC. This is also the mode you would update the firmware for your RC when connected to your PC. Your PC provides power to the RC in this case.

So, when you connect a power source to a USB port in A or OTG mode, it's like connecting two power supplies together against each other. The RC is a power source. The power bank is a power source. Bank is pushing power in excess of what the RC is pushing. Not a good way to go, even if you happen to be getting away with it. You do take the risk of damaging the RC's power circuits to the USB port.

In other Mavics with the full size A port on the bottom, when you use this port to connect to your phone, you are free to use the side port as B mode to charge your RC.
Not so with the Mini as it has only one port. A USB port can't operate in A mode for data and B mode for power at the same time. It's all A or all B.

If you do end up damaging the power circuit to the USB, you will either be unable to charge your RC, or your phone won't connect because it no longer sees any power on the USB bus. Maybe both.

It's your system, your risk. I don't recommend anyone else taking the risk.

Danman ( and guys )....

I still wonder, why not just open the controller, disconnect the internal battery, run + & - leads from controller board to the backside of the controller case and attach a larger capacity battery pack on the back? Match the voltage, of course, but disconnect the internal battery completely and connect a large 5000/10000mah battery pack externally. Should work, right? Maybe 4 Samsung INR18650-30Q 15A 3000mAh Flat Top 18650 Batteries?

IF controller uses 3.7v, that would 4x the battery life. IF it uses 7.4, then double the capacity as internal. Thoughts?????

 

[penuela.lance]

That sounds like a defective remote, maybe defective cable. You should get at least 2 full flights out of it.
Can you try a different phone just to be sure?

Ill try all your recomendations. Thanks sir. Ill try iphone if all hell fails. Ill get it back

 

[DanMan32]

Danman ( and guys )....

I still wonder, why not just open the controller, disconnect the internal battery, run + & - leads from controller board to the backside of the controller case and attach a larger capacity battery pack on the back? Match the voltage, of course, but disconnect the internal battery completely and connect a large 5000/10000mah battery pack externally. Should work, right? Maybe 4 Samsung INR18650-30Q 15A 3000mAh Flat Top 18650 Batteries?

IF controller uses 3.7v, that would 4x the battery life. IF it uses 7.4, then double the capacity as internal. Thoughts?????
View attachment 92212

I'm not voiding the warranty or adding additional weight to it. Better to just figure out how to limit current going to the Android without potentially breaking the data connection or making it potentially unstable.

 

[CareyL]

... Better to just figure out how to limit current going to the Android without potentially breaking the data connection or making it potentially unstable.

I think that is what I have done. Phone, (or tablet), stays charged and MC is happily in data mode.

 

[nn666]

I'm on iphone so have no issues. Can easily get through all 3 batteries with at least 2 battery squares remaining.

 

[DanMan32]

I'm on iphone so have no issues. Can easily get through all 3 batteries with at least 2 battery squares remaining.

Yes we know. iPhones have the API to allow the app to disable charging from the USB port. Androids natively do not so Go/Fly can't disable charging for Android systems. Here lies the problem. We have to somehow trick the phone to thinking the RC is incapable of providing charge current, without causing data disruption because power/voltage on the USB power bus dropped. USB standards expect sufficient power on the USB even for data only.

 

[KimiTs]

Hi everyone, I have a similar problem with android and ipone. When I use the Samsung S8 +,controller battery it takes 20-25 minutes because the controller consumes a lot of energy to charge the androids, and when I use the ipone6,ipone battery runs out in just 10 minutes.
I will replace the battery in my iphone to see if I have resolved the problem as one of you said earlier.Sorry for my bad English.