When all is in top condition, this should not happen... Measured leakage should be maximum 0.05Amps. This means every hour bites that amount of capacity from battery.
The leak -calculation, how long healthy batt lasts, seems 'simple', however has lots more nuances than this... but heres the basic:
10hrs.. 10 x
0.05 = 0.5A
100hrs 100 x 0.05 = 5A
1000hrs 1000 x 0.05 = 50A
As your battery has 60A capacity, standing 1000 hours means THE END with mentioned leak of
0.05Amps. ...Alltogether about 40 days...
My Maxima measured leak current is now 0.01Amps when alarm is ON. That means 200days standby...
Wassup Leak: Myriad reasons from inadequate charge, to -any- accessory leak voltage to ol battery.
Note: I have currently a cutoff switch on radio/light dimmer circuit ... which leaks VERY LITTLE = 0.14Amps. Two months would definitely kill the batt.
Check this and measure your leak:
formatting link