Read post #10 where I suggested a timer and how to use it.
A simple solution used by some is a timer which powers the charger for 2 hours per day. Use a mechanical one and after flying for the day set it max., right after normal turn off time ,switch it on (manually)and it will charge for 24 hours then two hours per day.
This means has been in use for many,many years
I use to do this myself at times but in more recent years after switching to Sanyo Eneloops in my Transmitters it is no longer necessary as they will stay charged for months on end if not used.