- Batteries?
As an IT specialist dealing with laptops and various mobile eq, I have a lot of experience with LiPo batteries. The first time you charge them a clock starts ticking. Every charge "kills" a little of the battery's capacity (very little but...) - so the trick is to charge them as few times as possible and as efficient as possible. - and know how to properly maintain you batteries for long life and safety.
Charge everything up JUST BEFORE flying – not days in advance to keep them at max: Charge, the use them as quickly as possible after.
Don’t discharge them below 20% if possible (deep charging from less stresses a LiPo battery's cells and chemistry and kills max charging cycles= shorter lifespan).
Do not charge them directly after flight or hot (eg if left in the car/sunlight). Let them cool off to room temperature first.
Do not charge them after flight just for storage, if you don’t plan to fly more that day. Leave them at the current charge. By doing so, you will charge them more effecient, then "topping up" just before flying.
LiPo batteries are best stored at max 50% or less charge for safety. Don't worry, these intelligent batteries will make sure you never pass the critical line where the cells collapses. Infact set your automatic discharge no of days to 5 rather then 10 days in the battery menu for each one, so the you make sure, they discharge if you come home with a full one. Same goes for taking your batteries on an airplane – never more the max 50% so the current have somewhere to go if that battery malfunctions during storage eg due to short-circuit, liquid, moisture etc.
Never charge LiPo batteries unattended. These flying batteries are high voltage (typical 15-18V) and the chemicals inside can burn at up to 7-800 Celsius. You really can’t stop a LiPo battery burn out not even with water or foam. In the event of a burn- throw the burning battery outside with a shovel (or anything metal - DON NOT TOUCH!) on the lawn and let it burn out.
Check that connectors are clean and that there are no cracks in or deformations of the battery case. Check for leaks (green/blue fluid).
Never fly with a broken swollen battery: It's neither safe nor worth it. ;-)
PS - pardon my English - I'm from Denmark.