You’ve probably encountered a traditional, lead-acid battery in your lifetime, but you might be less familiar with deep cycle batteries — unless you have experience with recreational vehicles, boats or golf carts. But what’s the difference, and does it really matter which battery type goes into your vehicles?

Traditional lead-acid batteries and deep cycle batteries are actually designed for different uses and power output, so knowing the difference between regular lead-acid and deep cycle batteries is crucial. Choosing the wrong battery for your vehicle could leave you with a dead battery, or a lack of power to get from one point to the next — or it could cause long-term damage to other car parts, like the alternator.

Before you start shopping for vehicle batteries, it’s important to know the differences between traditional batteries and deep cycle batteries, how they work and when to use them.

What Is a Traditional Lead-Acid Battery?

A traditional lead-acid battery is probably what you think of when you imagine a car battery. This type of battery typically has six connected cells inside. There are lead plates and lead dioxide plates within each cell. The lead-acid battery has a positively charged cathode, a negatively charged anode and sulfuric acid, also called the electrolyte.

How Does a Lead-Acid Battery Work?

To provide power to the vehicle, the electrolyte reacts with the lead plates to create ions, which also react with the lead plates and create lead sulfate and hydrogen. As these ions move around to the cathode and anode, they produce the electricity needed to power up the engine. The reactions are reversed to recharge the battery.

This setup allows a traditional lead-acid battery to supply a short burst of power to start up the engine. The continued energy supply to keep the car moving is actually provided by the alternator after the battery powers up the engine via chemical reactions.

What Is a Deep Cycle Battery?

Deep cycle batteries are designed to handle states of deep discharge, or depth of discharge (DoD), which is how much of the battery capacity is used in one full discharge of the battery. There are different types of deep cycle batteries.

Flooded deep cycle batteries will require the user to refill the electrolyte levels to maintain the battery, while sealed lead-acid batteries are a type of deep cycle battery that requires little maintenance and are spill-proof. This quality makes deep cycle batteries a good choice for recreational vehicles that may experience a lot of bumps and vibrations.

How Does a Deep Cycle Battery Work?

Deep cycle batteries have thicker lead plates compared to traditional lead-acid batteries, allowing the battery to provide longer sustained amounts of electricity but less power compared to traditional batteries. These batteries can withstand 80% or higher DoD, although the lifespan of the battery will benefit from keeping the DoD above 50%.