I have been told that the batteries for the Phantom will turn on and discharge down to 50-60% after a set period of time. Do the batteries have to be in the quad copter or can they be left in the case for this to happen? I have set the discharge to 5 days, but they are still at the charge level when last used.

The batteries will go into this self discharge after the set amount of days whether in the quad' or not. You set discharge to five days , so, after five days the batteries will begin a slow discharge to 50-60 % (This takes about two days from 100%). Assuming of course that the batteries have been used since the last discharge time was set. (Perhaps you changed it from ten days to five, the batteries need to receive this instruction from DJI Go).

You can change the settings in your DJIGO4 application.  I think it is 3-5-7-10.   They can be left in your case

I change it to 5 days. Will the lights come on so you know they are discharging?

Aardvark Posted at 2017-4-4 14:39
The batteries will go into this self discharge after the set amount of days whether in the quad' or not. You set discharge to five days , so, after five days the batteries will begin a slow discharge to 50-60 % (This takes about two days from 100%). Assuming of course that the batteries have been used since the last discharge time was set. (Perhaps you changed it from ten days to five, the batteries need to receive this instruction from DJI Go).

Just to add to Aarvark's advice, if you have more than one battery, you need to set the discharge time individually for each. For example, if all of your batteries were set to start discharge after 10 days, and you decide to change to, say, 5 days. With everything powered up you set that via the GO app. Then if you power down the craft, insert another battery and power the craft back up, once the RC/app reconnect it'll show your discharge time as 10 days again. So you reset that battery to, say, 5 days also.
In other words, the app obtains the battery setting from the battery itself, so you need to set consistently for each.

Also, note that if you're curious and tempted to press the battery button to see if it's yet discharging, that'll reset the 'count down'.

So how many days is optimal? Well, here's a good point of discussion. These are current gen batteries with their own 'smarts'. I personally don't believe that they need to be discharged between each use, unless we're talking weeks between use. So, knowing my likelihood to only be flying on the weekend, I set mine to 7 days. That way, if I don't get to fly them the next weekend, the batteries will commence discharge on that weekend (and for the weekend after that I'd fully recharge them again before use). In other words, if I last fly on a Sunday and I don't get to take the craft out the following weekend, it'll start to discharge that following Sunday.

The other variable for consideration here is what you do with your batteries after flight.  I fly with batteries down to ~45%, then I fully recharge them when I get back home in readiness for the next weekend of flight. If I don't fly that following weekend - see above.

Just my personal approach. Happy for constructive input and views...

Thanks Punchbuggy this helps, as all the other replies

Everyone here has pretty much hit the nail on the head.

FYI, there is a battery update available that enhances long term storage. You would be wise to update all of your batteries.

Rodger8 Posted at 2017-4-5 10:53
FYI, there is a battery update available that enhances long term storage. You would be wise to update all of your batteries.

When it became "live" ?

adrian8891 Posted at 2017-4-5 12:12
When it became "live" ?

Last release for the P4 in November 2016:  1.2.602
But battery firmware will also be updated in the next P4 firmware release within the coming week. You know when firmware is being updated when the middle two LEDs on the battery are blinking.

adrian8891 Posted at 2017-4-5 12:12
When it became "live" ?

Sorry, you lost me.