Discharging batteries into a power bank

[propflux01]

You just have to keep an eye on it. The charging lights on the battery show the charge level reducing the same as they do when in the drone. I normally stop it when there are two lights on and the third light flashing. Only have one battery in the hub at any time and keep checking it. No way to set the discharge level.

I guess so. Right now I just run Them down on the drone as much as possible and keep them at the 2-bar level. You’d think they’d come out with a “DJI smart battery optimizer “ that could discharge them without the 9 day wait!

 

[Droning on and on...]

Sounds good, but how do you know when to stop the discharge so the batteries don’t get ruined?

The DJI Intelligent Battery module knows how to do that all on its own. No worries.

All you'll end up with is a battery that needs to be charged

 

[propflux01]

The DJI Intelligent Battery module knows how to do that all on its own. No worries.

All you'll end up with is a battery that needs to be charged

I understand that, I just don't like the amount of time it takes to do it. 10 days on a full charge to me, isn't good on the batteries., And they are not cheap.

 

[Droning on and on...]

I understand that, I just don't like the amount of time it takes to do it. 10 days on a full charge to me, isn't good on the batteries., And they are not cheap.

I was referring to preventing over-discharge and damaging the battery. You can't over-discharge a DJI battery.

 

[Heckmaniac's Drone]

Just saw this in Amazon - going to see if this configuration will work. Problem I’ve been having is the DJI hub has a USB-C that will both discharge or accept charge, but most power banks have a pd port in/out so when I’m trying to recharge Air3 battery I found in fact that the Air3 battery is discharging back to the power bank. I think this newer hub will only allow input from power bank to the Air3 battery (we’ll see if it works when I get it). Also ordered a very inexpensive power bank that I’ll have to see if it will work.

 

[GadgetGuy]

I was referring to preventing over-discharge and damaging the battery. You can't over-discharge a DJI battery.

Perhaps a more accurate statement would be that, except in flight, DJI batteries have circuitry designed to prevent over-discharge. You can certainly over-discharge a DJI battery in flight, by continuing to fly with it past all warnings and by simply overriding Autoland with full up left stick. You can even continue to fly for two additional minutes past 0% remaining battery.

 

[Droning on and on...]

Perhaps a more accurate statement would be that, except in flight, DJI batteries have circuitry designed to prevent over-discharge. You can certainly over-discharge a DJI battery in flight, by continuing to fly with it past all warnings and by simply overriding Autoland with full up left stick. You can even continue to fly for two additional minutes past 0% remaining battery.

Are you sure this will discharge <3V per cell causing damage, or will the BMS cut off the power before damaging a lipo cell?

0% really isn't useful, lipo SOC is at best an approximation. And to a DJI BMS, what does 0% mean?

To be very clear, when I say over-discharge, I mean allowing damage.

 

[Kilrah]

The time the BMS cuts (potentially after being at 0% for a while) is still a safe voltage for the cells. There's margin for it.

 

[GadgetGuy]

The time the BMS cuts (potentially after being at 0% for a while) is still a safe voltage for the cells. There's margin for it.

Indeed.

Are you sure this will discharge <3V per cell causing damage, or will the BMS cut off the power before damaging a lipo cell?

0% really isn't useful, lipo SOC is at best an approximation. And to a DJI BMS, what does 0% mean?

To be very clear, when I say over-discharge, I mean allowing damage.

You can currently keep the drone in flight until the battery voltage can no longer sustain flight, well below 3V on any given cell, by manually overriding Autoland. DJI's early BMS used to shut off the battery as soon as any single cell dropped below 3V, even when in flight, to "protect the battery." Fortunately, this has been changed, as nothing is worse for a battery and the aircraft than dropping like a stone from 50 feet above the ground! Clearly, DJI's current 0% remaining battery is an artificial 0%, leaving 2 minutes of flight in the tank. 0% remaining is still above 3.5V per cell. It used to really be 0% remaining, and an impending crash.