I am going to receive my battery hub for my Phantom 3 Pro. While realising it charges the batteries one by one (not simultaneously), I think it is a good idea to add the following features to the hub:

1. To discharge batteries, so that we don't have to discharge using the drone
2. To charge / discharge batteries to 30% - 50% for long-term storage (as recommended by battery safety guidelines, pg.3)

I am not sure if these are technically feasible, but it will be great if these features are added by updating the firmware of the battery hub. This will save a lot of time waiting for the battery to be charged / discharged to required level and I no longer have to keep an eye on the drone during the process (kids at home =P).

Hi, jonesuki
Bet you've read our guideline very  carefully  . Thank you for your suggestions . I believe our engineers gonna take a consider of that .  That 30%-50% battery storage suggestion is great !

It is technically possible, I think we need to bring this idea alive! Thanks for your suggestions

You can also just program the batteries for one day and let them discharge themselves.  It takes a couple of days for them to come down when they start.

It is great to have positive reply from DJI. Hope to have the features in near future.
@G0N-Gary: I also think of lowering the discharge threshold to 1 day to facilitate auto-discharge. But it discharges to 65%, not the recommended 30-50% and takes more than 2 days (2 days to 65%, according to the guidelines), which is too long for me. Thanks for your suggestion anyway.

jonesuki Posted at 2015-11-16 05:42
It is great to have positive reply from DJI. Hope to have the features in near future.
@G0N-Gary: I  ...

There is no significant danger in programming your batteries to "half-discharge" over a two-day period. I have essentially been doing this since I bought my P3Pro back in mid-May.

That's the setting I routinely have my batteries set on (I have four batts and have never had a problem with this technique). If it seems like I can go flying tomorrow, I make sure my batteries are charged. If it turns out that I don't get time to fly, weather turns sour, etc., the batteries are perfectly for up to a few days. With the setting on each battery to self-discharge in a 2-3 days, they will discharge to approximately 50% - 60% and can sit on the shelf for quite some time.

There are a couple of things you can do to hurt your batteries:
(1) Never leave them in a situation where they can get really hot - like leaving them in your car on a hot summer day
(2) In theory, you can hurt your batteries by over-charging them. However, with the charger provided for both the Advanced and Professional P3 models, it's pretty difficult to over-charge any battery.

NEVER CHARGE YOUR BATTERIES WHILE UNATTENDED! If something *does* go haywire and you're not around....

If the place where you store your batteries is cooled by A/C or heated when it's cold outside, you've got nothing to worry about - just take the standard safety precautions and stop fretting.

Art - N4PJ
Leesburg, FL

aburkefl@gmail. Posted at 2015-11-16 20:24
There is no significant danger in programming your batteries to "half-discharge" over a two-day pe ...

Thanks aburkelf for sharing.

According to your experience, what is the amount of heat dissipated during auto-discharging process? I used to keep my battery in separate plastic bag and keep all the battery with my drone in backpack. I worried if the heat dissipated will cause any problem in my case.

And, I totally agree with you that battery should not be left unattended. Even if the auto-discharging function is available to battery hub, I will still monitor the battery from time to time. I just don't want to worry about missing the 30-50% target.

jonesuki Posted at 2015-11-16 08:13
Thanks aburkelf for sharing.

According to your experience, what is the amount of heat dissipated  ...

I honestly don't know the technique of why or how it works, but the Intelligent Flight Battery is indeed pretty smart. If you charge it fully and set the discharge for several days, it will get to around 50% and stay there for a surprisingly long time.

My four batteries sit on a shelf (inside, in an "environmentally controlled" area) for weeks at a time with no apparent ill effects. For whatever reason, once the charge gets down to the "storage" level (50% - 60%) they tend to stay in that range for a long time.

Look at it this way - the people who sell them have to keep them in storage capacity charge as well - otherwise there would be severe "shelf life" problems. So, with them being shipped around, stored in your favorite hobby store as well as at DJI, etc., they almost have to be capable of a reasonable charge for quite some time.

Even the old-style LiPo batteries exhibit similar effect. Once the storage charge is set, the battery tends to hold that level for an amazing amount of time.

My Phantom and Chroma batteries (the Chroma batteries are in a "cartridge" format similar to the Phantom batteries) tend to just sit on the shelf. My other "standard" LiPo batteries are maintained in an ammo box (solid steel).

I don't have any reasonable equipment to measure heat loss either during charge or discharge. As far as heat is concerned, I make sure a discharged battery cools off significantly before charging it again.

Art - N4PJ
Leesburg, FL

DJI-Tim Posted at 2015-11-15 22:37
It is technically possible, I think we need to bring this idea alive! Thanks for your suggestions

There's a related feature I'd like to suggest: the ability to charge a battery to the 50% level. I do this now when after a flight when I know I won't be using the battery for a while. In fact, the features could be combined so if the battery charge is over 50%, it would be discharged to that level, and if below, charged to 50%.

I agree this would be good.  I just rated this on Amazon 3 stars because the batteries and hard to put on the hub and still only charge 1 at a time.  

May I know if there is any timeline or progress on the titled?

Regarding temperature rise when discharging:  This is how I discovered mine was discharging the first time I ran into it.  It felt just a very slight bit warmer (in the middle of the broad side of the battery) than the one that was not triggered to discharge yet.  I checked the temperature with my IR thermometer and found 1 to 1.5 degrees F warmer during discharge, and I've verified it several times.

AG0N-Gary Posted at 2016-1-4 12:14
Regarding temperature rise when discharging:  This is how I discovered mine was discharging the firs ...

Thanks AG0N-Gary for your updates!

Is there any update on the progress of this requested feature on battery hub, from DJI?

Could on use a 12 volt light bulb like a car tail light wired with alligator clips to discharge the batteries?

SpecialProjects Posted at 2016-3-23 14:50
Could on use a 12 volt light bulb like a car tail light wired with alligator clips to discharge the  ...

Yes, you certainly could use that rig.