Tractor batteries are different from standard automotive batteries. They have specialized sizes and shapes to fit in the tractor’s battery compartment, emit different voltages from car batteries, rely on a different charging system, and typically see different patterns of use from car batteries (more in spring, summer and fall and less in winter).
Like automotive batteries, however, tractor batteries eventually need replacement, but there is risk of confusing a charging system or starter issue with a defective battery. The following is a list of DIY and professional shop tests that can be performed to determine whether tractor batteries need replacement or some other aspect of the tractor engine system is at issue.
1. Load Test
A load test determines whether the battery is receiving and emitting electricity at the wattages and voltages it should. DIY load testers are available for prices ranging from £15 to more than £80. Opinion is mixed whether DIY load testers are effective, but they certainly require knowledge of how to remove a battery from the engine compartment safely and operate the load tester. An alternative to DIY load testing is bringing the battery (no need to bring the entire tractor) to a battery shop and have the staff there perform not only a professional load test, but other tests. Battery shops with staff who specialize in batteries and electrical servicing normally perform these tests better than generalist mechanics, but the latter are also an option.
2. Specific Gravity Test
This test for tractor batteries verifies the specific gravity of the fluid within the battery’s individual cells, which is necessary for good energy storage. Again, DIY kits for load testing tractor batteries are available, but require knowledge such as can be acquired by reading a New Holland manual from repairloader.com. Battery shops also perform this test, as do some generalist motor repair shops.
3. Headlights Test
Should tractor batteries pass the load test and specific gravity test, they can be placed back into the tractor and reconnected. Then start your tractor and drive it up to a wall. Turn the headlights on. With the headlights aimed at the wall and close to it, and the engine idling, give fuel to the engine. The reflection of the headlights on the wall should become brighte. If it does not, then some other aspect of your tractor’s electrical system is likely in need of servicing.
4. The Starter Test
This test is not so much a test as an experience. Should you have difficulty starting your tractor, especially in mild weather, and require too many revolutions of the motor in order to start it, chances are either your battery or some other component of the engine needs servicing. Overuse of a tractor’s starter can damage the starter and other motor components, and tractor batteries are much less expensive to replace than starters. Do not extract every last second of life you can from a failing battery! If you have difficulty starting, perform tests on your battery and your motor system immediately.