What Is A Deep Cycle Battery?

We’ve all heard it time and time again, a battery is a battery and there’s no sense in worrying about which one you end up with because they are all the same.

But can this still be true in these modern times in which we live?

To help you get a handle on it, we have prepared this article exploring the ins and outs of this topic. We will begin by answering the question – what is a deep cycle battery. And then follow this up with some specific uses of deep cycle batteries that you should consider before jumping into the market for one.

However, before we begin to break down the deep cycle, we should first explore the different types of batteries…

No, most certainly not. In fact, while car batteries and ones designed for marine applications may look very similar. However, they do differ from each other in some very important aspects.

In truth, even marine batteries can be broken down into three different types: starting (also known as cranking) batteries, dual-purpose batteries, and the topic of today, the deep cycle battery. While we will focus on this last type for most of the article, we will start by breaking down the important aspects of each type.

How does a deep cycle battery differ from Starting or Dual-Purpose options?

Cranking batteries, often labeled starting batteries, discharge large amounts of energy by design. However, they only do so for a short period of time. This means that these starting batteries are perfect for getting an engine started. These are what you would expect to find in an automobile or from an inboard/outboard marine engine.

This differs starkly from the deep cycle battery that is designed more for a continuous discharge of low level energy for an extended time. In fact, deep cycle batteries will often push power right up to the capacity limit, unlike cranking batteries that need to have a reasonable amount of juice left to turn over an engine.

Think drag racer vs. Dhaka rally racer…

A world class drag racer will explode off the line. And then blow away just about anything in a short, straight run to the finish line. This is the cranking battery, quick off the line, but just as quickly needing a rest on the sideline.

Deep cycle batteries are much more similar to the more durable Dhaka rally runners. These need to be quick and strong, but more importantly, they will run for mile after mile without interference from the outside. While most dual-purpose batteries can deep cycle, they won’t perform as well as a battery specifically designed to do so.

It’s not just about the amount of energy, but also how it is let loose…

While starter batteries only discharge a minute level of energy. Deep cycle batteries are built to discharge a larger percentage of their capacity for each pull on their reserves. This is known as a ‘deep discharge’ because you get a lot more than just the surface energy, as with a starter battery.

This means you’ll get less of the damage that is known to occur in starter batteries run in a deep discharge. This will greatly affect the overall battery life and performance.

Able to discharge up to 75% capacity without damage…

Often, deep cycle batteries can withstand discharging up to 75% of their capacity with no ill effects. Though it is advisable to check the manufacturer’s recommendations as some models are limited to a much lower level of discharge. You don’t want to kill the battery by attempting to pull more energy than is recommended. It will have a massive effect on the life of the battery.

As you probably realize, deep cycle batteries are excellent for those applications that need a small amount of energy for a prolonged period of time. Starter batteries cannot compete with the slow, steady, and a constant supply of energy that deep cycle batteries provide to appliances and other motors needing a stable energy supply.

One such example would be the best trolling motor for kayaks. These require electricity to power a propeller over an extended period. For this, a deep cycle battery is ideal. And they can even be linked in series when more power is required, like when running larger motors.

What are other typical uses for a deep cycle batteries?

The most general applications of a deep cycle battery range from use in smaller vehicles like forklifts, golf carts, or even motorized wheelchairs. They are also often used in navigational instruments and other devices within boats and ships, which draw energy from a deep cycle battery whenever the inboard/outboard motor is not in use.

Deep cycle batteries are best for solar power storage.

Larger deep cycle batteries are also often used for storage in a renewable energy system. Because of this, anyone with knowledge of solar or wind energy solutions will have had some experience with deep cycle batteries.

Before getting into the range of Amp hours available from the wide range of deep cycle batteries. We first need to explain what exactly this refers to. Because most deep cycle batteries on the market rate themselves with this unit of measurement, it’s wise to ensure we are all on the same page here.

Amp-hours or ‘Ah,’ as it is commonly shortened to, measure the amount of energy the battery can supply. The rating of 1Ah for any given battery means that you can expect one amp current over the space of an hour.

A range of sizes available in deep cycle batteries.

Larger deep cycle batteries these days generally come in around 100Ah, while smaller options start in the 25Ah up to the more common 50Ah batteries.

Note, 1Ah does not mean the battery will last for a full hour in all scenarios…

To clarify an important point, it will depend greatly on the level of current being pulled from the battery as to how long the energy supply will last. If your trolling motor or other electrical equipment pulls more amps per hour than the battery can provide, it will die much more quickly. For this reason, it is vital that you check the amount of energy required for your needs before making a purchase.

Hopefully, you now have a thorough understanding of deep cycle batteries. How they work and what they are best used for. If you need a battery that offers an extended supply of energy. Then we would recommend that you first double check the manufacturers’ recommendations for what Amp hour supply your motor or device needs.

Once you have done so, you simply need to find the right deep cycle battery for your needs. We would also recommend taking a look at our in-depth Best Trolling Motor Battery reviews to find out what’s currently available on the market.