Originally posted by SVT#95:
That thing is supposed to tell you if your water is low in the battery. If your cells are not covered with enough water and are getting exposed it will make the battery lose its charge quicker.
No.
It is a hydrometer. It's color is based on the specific gravity of the battery fluid, an indication of the state of charge. If the battery does not change to green from a trickle charge it can also mean that the battery is shot and needs to be replaced.
