Battery water level

[edwmama]

Can anyone tell me or educate me on this issue that baffles the heck outa me?

Besides my separate starter batteries I have two sets of house battery. One set consists of two 4D connected in parallel. Another set contains four 6V batteries in which 2 pairs are in a series which In turn are in a parallel connection. My question is. Why is it then when I go to top off the water the 4D never require water but the 6 V always do even though the 4D are my primary bats? I am using the 4D and they are always full and the 6V are back ups yet there always low every two months? Mysterious

Edwin




M

My question is

[S/V Illusion]

Are they co-located? Same ambient temp? Same vent caps? Same charging source and same voltage? Same age and condition? Difficult to make comparisons with so many variables.