Take a volt meter and check the voltage between the positive and the side of the battery, and check all round each side, and the top. if you get a reading of over .1 anywhere (excluding the negative terminal(s)), take the battery out and clean it off really good (Carefully) you don't want to get extra water inside of it , or dirt, etc.
Also check your water levels, only top off with distilled water.
My old battery had a reading of like 4 Volts from the positive to the side, i cleaned it off really good and got it down to .06 or something like that.
