It takes many components to keep a tractor running, but a healthy battery is necessary to get it started. Running a tractor provides power to the battery, which in turn is able to provide cold cranking power. In order for this to happen as it should, the battery itself needs to be in ideal condition. Before performing work on batteries, the cables need to be connected and the battery moved to an accessible location if possible. Remove the negative cable first and secure it in a location where it is unable to make contact with the battery, then remove the positive cable and pull your battery free. Removing the battery in larger tractors can be difficult, and in those cases you will have to attempt to clear enough work space around it to perform the necessary maintenance.
Corrosion is a common occurrence on battery posts and cable connectors. New connectors may also leave paint chips behind. Since all of this can affect your connection, it is important to clean the corrosion away. A wire brush is useful for this purpose as is a mixture of 3 parts water mixed with one part baking soda. Also capable of doing the job is soda. Once your battery posts are connectors are clean of corrosion, you can use felt washers or dielectric grease to prevent or slow its return.
If the connectors themselves are beyond repair, a new set can be added. To do this, start by undoing the bolts on the old terminals and removing them. In some cases, these may have to be cut off, but be sure to salvage as much cable as possible or you will wind up needing to replace those as well. Clear away any oxidation that is present and affix your new connectors; using crimped ring connectors may be necessary depending on the type of fix you are performing, such as in the case of cables with molded wires. Buying unpainted connectors or brushing paint off of them prior to use is also wise as it will save you the trouble of having to do so later.
Another of the battery requirements that must be met is a proper liquid level inside the cells. As batteries are being used, the liquid in the cells is changed via chemical reaction into gas form. This causes a slow loss of water over time, so it is not something you need to attend to on a daily basis, but it does need to be kept in mind and checked periodically. On some batteries you will be able to see the liquid level through the side of the case whereas on others caps will have to be removed for you to be able to see water levels. If they are low and your battery is refillable, go ahead and add distilled water to bring the levels up but be sure not to overfill cells. It is also imperative that you use distilled water; tap water has minerals in it that can be harmful to battery health.
In the event that you are not planning to use a tractor for a while, disconnecting the battery will help it retain its power, as will storing it in a cool, dry location. If you are bringing your tractor back to work after a winter off, now is the time to check your battery and make any necessary adjustments to keep it operational for the months to come. Always be sure to wear protective eyewear and cover exposed skin or be prepared to promptly wash off any battery acid that comes into contact with skin as it is possible to be burned. Battery acid can also eat through clothing, so if you are particularly fond of a pair of gloves or have a favorite shirt, do not incorporate those items into battery handling.
A little bit of periodic battery care may be necessary to maintain the ability to start your tractor, but putting in that work is far better than having your tractor not crank in the morning. If battery maintenance is not your favorite thing, you can purchase a maintenance-free battery to reduce the guesswork. These batteries have an indicator on them that tells you if the battery is good, needs charging, or should be replaced. While this is handy to have, these batteries unfortunately do not clean their own terminals, so you can reduce your battery workload but not eliminate it completely by any means.