For years, deep cycle batteries have provided moving energy for electric construction equipment. During this time, the technology around deep-cycle batteries has not changed much, and there are no basic recommended care and maintenance practices.

However, there are many misconceptions and bad practices when it comes to maximizing deep cycle battery life. In general, four things cause these batteries to be replaced before they fail: improper charging methods, improper testing procedures, and - specific to water-rich lead-acid technology - watering methods and freezing.

There are many things that can lead to poor charging behavior. Low-end charging, for example, is cumbersome for batteries. Ideally, a deep-cycle battery should always have more than 80% charge. Any lower charge will cause the batteries to sulfate, or self-degrade, causing them to further lose capacity. Another bad charging practice is to fully discharge the battery before charging. This is a misconception, as battery manufacturers may advertise that their batteries have a certain number of charge cycles. The rating of the battery is the number of ampere-hours in and out, so it does not matter how many are removed or replaced in each cycle.

Another possible source of this misunderstanding is the power tool industry and the nickel-cadmium battery technology they use. Because nickel-cadmium batteries create "memory", it is necessary to ensure that the battery is fully discharged before charging, so that the battery does not self-limit. This is not the case with deep-cycle, submerged lead acid or absorption glass-pad batteries. Similarly, the ideal way to charge a deep-cycle battery is to maintain an effective charging strategy that keeps the battery's charge state above 80%.

Another cause of early battery failure is the use of improper test procedures. This problem can be easily solved. Many people will use a load test or test device that starts the battery to determine if there is a problem with the deep-cycle battery. Starter batteries and deep cycle batteries have very different designs to achieve their intended purpose. They react differently to tests and should be tested differently for each battery. These starter and battery load tests and devices simply cannot be used to determine a deep-cycle battery failure, as they may produce test results that result in good batteries being replaced due to incorrect information.

Another major cause of premature battery failure, specific to submerged lead acid (FLA) batteries, is the watering practice. Machine owners realize that batteries need to be watered regularly, but in the world of quick rentals, they often can't find the time. Many machine operators do not know that batteries need watering. Every time a FLA battery is charged, they evaporate water, and although the amount is small, it increases over time. Eventually, the liquid level inside the battery drops below the level of the lead plate, causing the battery capacity to decrease. When watering the battery, only use distilled water, as tap water contains minerals such as iron, which can cause the battery to fail prematurely.

Finally, one of the simplest forms to avoid premature battery failure is battery freezing. Again, this problem is specific to submerged lead-acid batteries. When the battery is discharged, they convert the battery electrolyte from sulfuric acid to water. The more the battery is discharged, the higher the concentration of water. So naturally there will be a point where there is enough water to freeze. At 20% charge, the submerged lead-acid battery will freeze at 5°C. While the problem is simple, the solution is just as simple. Do not leave the battery low in cold climates. Just like the other issues pointed out in this article, people need to be aware that there is a problem so they can avoid it.

In order to maximize the life of the deep cycle battery without sacrificing the function of the machine, use good charging methods, proper test procedures and equipment, water the submerged lead-acid battery regularly, and do not leave the battery in a low charge state in cold weather. These simple changes can dramatically improve performance and extend the life of deep-cycle batteries, providing a way to minimize battery maintenance and repair costs over the lifetime of an electric-powered machine.