What Are Deep Cycle Batteries?
Simply put, deep cycle batteries are batteries that are designed to be deeply discharged and recharged many times without negatively affecting their life span.
Everyone is familiar with automobile batteries. They are 12 volts and most of them are of the lead acid chemistry type. More on that in a minute. These automotive batteries are designed for a very specific purpose. To start your vehicle. They are capable of producing enormous amounts of power for very brief intervals.
They do not like to be deeply discharged. Every time you leave your lights on and need to have a jump-start or your battery connected to a charger, you are risking permanently damaging your battery. Not because you recharged it, but because you let, it get too low in the first place.
When you allow this type of battery to become deeply drained, the battery grows deposits on the inside, which is called “sulfication”. This generally cannot be reversed and will prevent the batteries from being fully recharged in the future.
Herein lies the marvel of deep cycle batteries. There are many uses for them. To name a few. Electric vehicles, trolling motors for boating, RV camping, remote communication stations, and alternatively powered homes that make their electricity with solar panels, wind turbines, or micro hydro turbines.
Deep cycle batteries are generally manufactured in either 6 volt or 12-volt models. There are others but these are the most common.
There are a few different types of deep cycle batteries. They each are made up of unique chemical properties. There are flooded lead acid, gelled, and AGM (absorbed glass mat) types. We’ll discuss the different types a little later.
Deep cycle batteries are usually more robustly built than starting batteries. They are specially designed to go through many charge / discharge cycles throughout their life span.
Types of Deep Cycle Batteries
There are three main chemistry types of deep cycle batteries. The first is what is called flooded lead acid batteries. These are the most common variety. They consist of several thick lead plates encased in a hard plastic battery shell. The battery is then filled with an acid called electrolyte. The plates are wired together in such a manner as to produce the necessary voltage. As these batteries are charged, the chemical reaction produces hydrogen gas which is very explosive. Precautions must be taken to ensure these batteries are charged in a well ventilated area and not exposed to fire or electrical sparks. Over time, the electrolyte level in this type of battery must be replenished by filling with distilled water.
The second type is called a gelled battery. The electrolyte in a gell cell battery is mixed with a silica additive which causes it to set up or thicken. These are no maintenance batteries which means you don’t need to add electrolyte.
The third is called AGM or Absorbed Glass Mat. The Absorbed Glass Matt construction allows the electrolyte to be suspended in close proximity with the plate’s active material. In theory, this enhances both the discharge and recharge efficiency. These are also no maintenance batteries.
What does this all mean to you? For most of your applications, you will want lead acid batteries. They are simple to maintain and the most inexpensive to buy.
When electricity is applied to the deep cycle battery terminals, a chemical reaction takes place. This process stores up energy. When you use the power from the battery by hooking it up to a charging source, the chemical reaction reverses.