They’re lithium ion batteries, so slower charging is better, and only charging them up when you’re about to use them is best.
Stick with USB-c chargers ( or obviously the old style usb to usb-c cable that the anafi came with to charge at usb 1 or usb 2 standard 2 amp or leas ), using usb to charge allows the internal circutry of the battery to decide how much and how long to charge, and for the thermal fuses to cut out charging if it gets too warm in there.
There are battery chargers that you drop the battery in and it charges it directly - they’ll work and might be faster, but this isn’t good for the battery, you want it charged slow and using the balance charge for the individual cells.
Charging it fully and discharging it fully will damage it, but you kind of have to balance that against wanting it to be fully charged before flying. You won’t really get that much extra use / less degradation out of a batter if you, for example, never charged it over 90%.
If you do manage to run the battery down below 20% while flying, it’s a good ide to get it charged back up above 50% as soon as possible ( allowing for a bit of cool down time after flight, of course ).
Excessive heat kills the batteries. Charging them while they’re extremely cold hurts them as well, and you’ll get reduced runtime in the cold, though their internal resistance will warm them up on their own. Cut your runtimes in half when below freezing, and try to keep them warm as long as possible before and after use, like in an inside jacket pocket.
If you’re charging them the day before, top them up to 80% then finish that last twenty just before you’re ready to go flying. Storing them put them away between 50 and 80%. If you leave a charge in them they will, after two weeks, slowly discharge themselves on purpose then go into standby mode.
Big impacts can also damage batteries like this, more than other chemistries. If you crash, be mindful the next time you charge and fly the battery, and don’t use a batter that has swelled up at all, swelling is a sure sign it’s going to short, catch fire and explod if you try to continue using it.
You’ll probably get 100 full flights out of a battery before you notice any degradation. Some guys get more, some less, whether that’s due to usage patterns or quality control from manufacture is anyone’s guess.
Batteries are somewhat expensive, but you end up paying 1-2$ per hour of flying if you just toss it at 50-75 hours of use.
