A few years back I worked for a major golf car company as a service tech. and let me tell you, you have never seen corroded cables as much as I have! We tried everything in the world to stop it.... then we discovered roofing tar! yes the stuff you can buy in the gallon container to go up and re-seal around your chimney. We would remove the cables, clean the terminals (wire brush), put new cables on, hose the batteries down with a strong stream of water, let dry, then "PAINT" on the roofing tar sealing the post to the battery case. This stops the oxidation from starting with the batery acid that is emited from the battery caps during charge times. If you battery is a "MAINTENANCE" type (has removable caps), take a look at the caps themself. there should be a rubber seal for each cell that the cap covers and the caps also have vent holes in them to vent the battery during charging.....see where the vents are, they may be venting right onto a terminal, if so just rotate cap or swap caps around until they are positioned away from the terminals (posts).