About Deep Cycle Batteries

Deep cycle batteries are all around us. If you have ever had to charge your car battery, you probably noticed that the charger has a setting for starter and another for deep cycle. Using the starter setting will charge the battery fast and the deep cycle will charge it more slowly. While this may be true, it is not the purpose behind these settings. The battery may be a starter battery or a deep cycle battery. There is also the marine battery which is a hybrid of the starter and deep cycle. Today we are going to take a closer look at the deep cycle battery. First we will discover what makes a battery a deep cycle battery. Next we will examine how deep cycle batteries are made and finally, we will explore some the things we use deep cycle batteries for.

Definition
Before we can address the deep cycle battery, we need to know exactly what we are talking about. A battery is anything which stores energy for use at a future time. When we talk about deep cycle batteries we can narrow this definition considerably. The energy stored in a deep cycle battery is electrical in nature therefore we can discount batteries that store heat, radiation or any other form of energy we can think of.

This does not mean that all batteries that store electrical energy are deep cycle batteries. The batteries used to power flashlights, for instance, are single cell batteries, not deep cycle batteries. Deep cycle batteries are composed of multiple cells. Each cell has an anode, cathode and electrolyte solution.

Deep cycle batteries use solid plates rather than sponge plates. They are designed to discharge up to 80% of their stored energy before recharging. Starter and marine batteries would fail quickly if they are exposed to this level of discharge consistently.

Construction
The anode and cathode are collectively termed electrodes. Each electrode is composed of a metal or metal alloy. As stated above, these electrode are solid plates in the deep cycle battery. Marine and starter batteries use sponge plates. Think of a sponge plate as being honeycombed, like the cross section of a beehive.

The electrodes are composed of lead or lead alloys in the majority of cases. The electrodes are pressed into solid plates that are fitted inside the cell. Each cell in a lead acid battery supplies about 2 volts. A 12 volt battery would contain 6 cells. The thickness of the plates will impact the lifespan of the battery. As a battery goes through discharge and charge cycles, the plates gradually erode. Eventually the electrodes will be too thin to effectively conduct electrical current and the battery will need to be replaced.

The electrolyte solution is typically an acid solution but can be just as effective when alkaline based. The term solution would imply that it is liquid. This is often true however, gels and Absorbed Glass Mat (AGM) variants are in use. AGM are also referred to as dry cell batteries even though this is not exactly true. Rather than letting the electrolyte solution fill empty space around the anode and cathode, the solution saturates a fiberglass mat which is sandwiched between them.

Application
Deep cycle batteries are more common in automobiles today than starter batteries. The starter battery is designed for a larger output of energy in a short time. Which is exactly what you need to start your car. However, there are more devices in our cars that need constant energy over extended periods of time. The stereo and video systems that are increasingly prevalent in todays' cars are perfect examples. The deep cycle battery is ideally suited for these types of applications.

The increasing focus on finding and using renewable energy sources is providing ample opportunity to employ deep cycle batteries. Solar panels are used to capture the suns energy. Connecting the panels to deep cycle batteries is an ideal way to store that energy for future electrical use. There are some obstacles to be overcome. The battery will release the energy in direct current (DC) form. Many of our everyday appliances require alternating current (AC) for their power needs. Use of a power inverter is often the only solution. By inserting a DC to AC inverter between the discharging battery and the appliance, you are able to use a DC source to power an AC system. Our purpose is focused only on the deep cycle battery so it is up to you to research and examine all of the inverter DC to AC power options available.

Electric golf carts are extremely dependent on deep cycle batteries. Golf cart owners pay very close attention to the life expectancy ratings on deep cycle batteries. A five year rating is dependent on more factors than just the passage of time. Those 5 years are based on how how much of the batteries energy will be used before recharging. The next most important thing to consider is the number of cycles, how many times it can be recharged. A typical golf cart battery is rated for 5 years based on a 50% discharge for 550 cycles. The reality is that golf cart batteries are frequently discharged 80% or more in a day and then recharged each night. This brings the lifespan of the battery closer to 1 or 2 years.

Deep cycle batteries are a special kind of battery that has a variety of uses in our lives. The next time you need to charge your car battery, take a look at the battery itself and choose the setting most appropriate to the type of battery you actually have installed rather than how quickly you want to be driving again. The lifespan of your battery could depend on it.