Interesting article found elsewhere: Worth a read

Is the Smart Battery too smart?

"DJI Inspire BatteryDJI Inspire and Phantom batteries will automatically discharge to their storage capacity when left idle for set number of days. When this discharge process begins, both the built-in and DJIGO app battery indicators may show the battery at full capacity while it is already partially discharged (the capacity is derived from cell voltage, which may trick the drone into thinking that the battery is at full capacity). When the current is drawn, a sudden mid-flight drop in battery voltage occurs. To test this theory, I took four batteries on their first day into this discharge cycle and tried flying them on a cold day. The battery LEDs still indicated full charge, the DJIGO app showed them at 94-96% capacity. All four batteries have dropped to 70-80%within first minute of the flight, and then suddenly dropped to 3-6% forcing an auto-landing. This convinced me that this theory is correct. To mitigate this possibility, monitor the number of days till the battery enters the discharge cycle, only fly fully charged batteries, and hover for 10-20 seconds at the beginning of each flight and watch for any unusual drops in voltage. Many owners limit their flying in the winter, which means their batteries entering the discharge cycle more often, increasing the number of these incidents during cold season. This seems to be the most plausible cause of these battery related issues.

I found this on on onother site recomended by  a  forum member : mydogisdead ,  I think it is just good concise  information that i wanted to share

Safe and fun flying everyone - donnie

I think doing the hover test is good airmanship......it tells you lots of things

Harb Posted at 2016-2-28 17:40
I think doing the hover test is good airmanship......it tells you lots of things

   I always do that as well, it gives me a moment to make sure everything is working correctly. I push the sticks and make sure they are responding accordingly.  Make sure those packs have a fresh charge before flying!

Cheers Harb - donnie

I never let my batteries find their way into an auto discharge state.  After use, they'll be brought up to or down to the 50% level and left there till before the next flight.  Then juiced up to the 100% level before go time.  I also spool the engines up on the ground and let them spin for a minute, after that it's a minute low hover and check controls in the air, while the battery meter is running to check for any abnormal condition.  If all checks out, up in the air I go.  If I'll be flying in cold weather, I warm the batteries to the neighbourhood of 25c to 30c in the car, and have the back end of the Inspire dressed in a half inch jacket of closed cell foam.  I flew the other day in -19c and the battery temperature at landing was just over 30c, so no issues at all.  Also, in cold weather, I'm landing at the 50% level - sudden drop offs are not my friend...

stormtrooper101 Posted at 2016-2-28 18:09
I never let my batteries find their way into an auto discharge state.  After use, they'll be brought ...

  That is smart flying practices my friend ! keep those batteries warm and toasty

Cheers -donnie

That's why you have to charge your battery before the flight and keep them warm, especially in the cold weather. Thanks for sharing the info