So just realised that on android due to the various standards  the controller will automatically charge my oneplus Nord and there is nothing I can do about it.

So what are my supported options? Pick up a cheap second hand iPhone? What version is best?

Disappointing, but hardly DJIs issue.

Always fully charge your Android phone before flying, that way there will be only a small discharge from the controller. I use Android S8+ not a problem. Search the forum there are pages of discussion on this topic.

The controller has a larger battery (6200 mAh) than your phone (4115 mAh) and it uses less battery power on average, so it can last for many charges of the phone. I like that feature, since the phone/tablet is likely to go dead much sooner than the controller.

True.  I have a spare oneplus 5.  I'm currently putting a custom rom (lineage) on it to see if I can use it just with the DJI Fly app and another app that apparently stops the phone charging.  

This isnt a biggy, but a little annoying.

Has anyone tried to charge the controller while it's in use and connected to the phone? If that works then we could strap a powerbank to the controller if we haven't topped up everything before going flying.

Arbitrary Posted at 1-17 02:43
Has anyone tried to charge the controller while it's in use and connected to the phone? If that works then we could strap a powerbank to the controller if we haven't topped up everything before going flying.

does your controller have two ports?  Mine only has one, is this some sort of y-splitter needed?

I think I've solved my situation.  Just spent 2hrs refamiliarising myself with rooting android.

I've got my old oneplus 5 updated it, then rooted it and installed Battery Charge Limit and DJI Fly.  Seems to work a treat. I don't have a sim for it, but I can create a hotspot do download map data at the beginning just to get the maps and turn wifi off.

Skynet5 Posted at 1-17 03:17
does your controller have two ports?  Mine only has one, is this some sort of y-splitter needed?

I think I've solved my situation.  Just spent 2hrs refamiliarising myself with rooting android.

Yes.
There is the charging port at the bottom of the controller, and the  "phone connection port"  at the top, behind the phone holder/antenna. If the controller can receive power through the bottom port, while it's in use and connected to the phone, this should work. I'll try this out later and post what I find out (unless someone is faster and can do this before I have the opportunity)

Arbitrary Posted at 1-17 03:21
Yes.
There is the charging port at the bottom of the controller, and the  "phone connection port"  at the top, behind the phone holder/antenna. If the controller can receive power through the bottom port, while it's in use and connected to the phone, this should work. I'll try this out later and post what I find out (unless someone is faster and can do this before I have the opportunity)

hahaha. of course.  Feel stupid now!

Yes let up know how you get on.  I'll take my drone out for a quick 5 min test later today with my root phone and see what happens too. Should all be fine.  Looks to be.

For me it is whatever stops the battery draining causing an unnecessary increase in battery charge cycles on a battery is that is not end user replaceable.

So actually just took it out in the backgarden for a bit of a roof inspection.  Perfect.  The Battery Charge Limit app works a treat.  All operational and seems fine.  Nice. Also means I have a dedicated screen for the drone and not having to use my daily phone is good.  

Its a shame that not everyone has a spare android phone and the skills ROOT the device.  But for the people willing to give this a go it seems to resolve the issue.  IT would be so nice for this to be baked into Android for these scenarios.

I can confirm after more testing today, this works a treat.

Tested out today, without actually taking off with the drone due to poor weather.

I connected the power bank to the charger and the charger to the phone, then powered everything on. The battery lights on the controller were blinking left to right, indicating it was charging, and the phone was receiving power too. I could also connect to the drone just fine.

Please note that this is a relatively chunky power bank, capable of talking "power delivery" protocol. But i'm unsure if the controller does. So this may not work with every power bank out there.

I don't think I'll bother doing this on a normal day, but it's a nice option if I've forgotten to charge. And if the controller battery ever starts getting worn out and performing poorly I know I have this option.

Arbitrary Posted at 1-19 13:15
Tested out today, without actually taking off with the drone due to poor weather.

I connected the power bank to the charger and the charger to the phone, then powered everything on. The battery lights on the controller were blinking left to right, indicating it was charging, and the phone was receiving power too. I could also connect to the drone just fine.

Good to know. Yeah I have an Anker with PD. Good to know this works. Thanks for reporting back.