Surprisingly, when you all assume Maintenance Free battery doesn't require filling up water. I've tried once opening the caps by removing the sticker of a maintenance free battery. Caps are hidden underneath the sticker.
I actually just changed my car battery last year, to INCOE brand, non-maintenance free (cause I dont believe in this MF battery thing), and during it's lifespan until today, I think I've only filled up once and only once so far. After that last fill, Water level so far still okay until today. Doesn't go down to below LOW level.
Few times I left my car for 1 week (go overseas) and after I come back, it still starts at 1 crank only. (And the starter cranking sound, sounded like I just started my car yesterday) . And once I started the car, even with small lights turned on (just to see the gauge)
Only thing I remember is when I am going overseas, I just manually lock my car (in the car porch) ; i don't turn on the alarm, cause I believe that small flashing LED alarm which flashes every 1-2 seconds X 60 mins X 24hours X 7 days , will slowly drain the battery power.
BTW, INCOE brand is quite a good brand and cheap brand, although imported/made in Indonesia
Car Batteries, What brand do you use? Why?