You can replace a 6-volt battery in a golf cart by removing the old battery and then connecting the new battery to the battery bracket. Thoroughly clean the battery compartment, and allow the batteries to charge through several cycles to complete the process.
In most golf carts, the battery compartment is in the front in a plastic container. Remove the top of the container to expose the batteries. Modern golf carts feature several batteries connected to each other with a battery bracket. Detach the battery bracket, then carefully remove each of the dead batteries. Recycle them, if possible.
Using a solution of baking soda and water, scrub out the inside of the battery compartment. Golf cart batteries are prone to corrosion, which can damage the cart's electrical systems. Clean the battery bracket and examine it for signs of damage. Thoroughly dry the inside of the battery compartment before moving on.
Place the new batteries into the battery compartment one at a time, oriented identically to the old batteries. Remember to check each battery's expiration date to ascertain its quality and age. Reattach the battery bracket, preferably with a small dab of anti-corrosion gel on the contact. Close the battery compartment, then begin charging the golf cart. New batteries require several charge cycles before reaching full capacity.