or if yuu're hardworking enough.. remove the negative terminal of your battery everynight and plug it back when u wanna start.
or change to a bigger size battery NS70.
probably u can install a standard volt meter to keep your voltage in check, see if your alternator is charging the battery enough.
If you wanna check for any open circuit, wire exposing, remove the positive terminal in your battery, get a bulb and connect the 2 wire at each end. make sure all your doors are close, if the bulb lights up probably there's an open circuit. not sure about this trick. I tried it myself once.
or you can get those voltage management system.