I was so glad when I could hook my batteries up to a real charger, balance charge, and see each cells status.Eleven, I usually travel with 8, I've noticed according to my Graupner a much more sophisticated charger than the Yuneec (what isn't) that two of the batteries have serious issues with cell balance (could this be a reason for them dropping from the sky)...I'm no longer using those for flight. BTW I flew 5 batteries yesterday with latest firmware...very solid great flying testing various features.
3 I want one more.
I keep them at storage voltage, charge up the night before I am going to fly.
Keep the in the original foam case indoors.
I have a small foam cooler I keep them in at the field. Keeps them out of the sun and heat.
Just ordered one of those. I already had 2 batteries. I use the Yuneec charger and usually charge the day before use. I never leave them charging when I am away from the room. I store them in the foam case inside the hard shell backpack. I am making an adapter to use aftermarket batteries.
That's just the way you rollI have 5 batteries 4 of which are stored at full capacity in my car parked in the sun with windows up wrapped in a blanket soaked in gasoline with 5th battery plugged into car adapter in a constant state of charging.