I almost always used a Wallwart charger plugged into a cheap 24 hr light timer. The timer was set to charge for about 40 mins every day.

I would come in from flying and manually set the timer to a few hours based on how much flying I had done. Then next day and every day on the timer would switch on for a short top up charge.

I did this for 40 years and never had to worry about my batteries not being charged. I can only remember one battery failure in flight and that was in my hack Zagi.. The found the Nicad pack was well over 10 years old when I dug it out

Now I was using Nicads to begin with and moved over to NiMH. The odd LiPo I had [ mostly in Turbines] I charged the day before I flew removing them from the aircraft and placing them in an old cooking pot.