When you’re shopping for a deep cycle battery, it’s easy to get overwhelmed with the different terms and promises that many manufacturers use to market their product. What is a marine battery? Or a VRLA? But choosing a battery isn’t difficult if you know what to look for. Here are some things to take into consideration:
There are two categories of deep cycle batteries: flooded and valve-regulated (VRLA). Each has certain advantages and disadvantages. Here’s a brief overview of each:
Flooded Deep Cycle Battery
Flooded deep cycle batteries, also known as wet cell batteries, are characterized by their liquid electrolyte component, which is composed of sulfuric acid and distilled water. Users should regularly open the battery and perform routine maintenance, which includes cleaning and “watering,” or adding distilled water to replace the liquid that evaporates during operation. All deep cycle batteries have thick plates of the active material, which is lead in the case of lead acid batteries, which allow for sustained power generation and deep discharge.
Valve-Regulated Lead Acid Battery
Valve-regulated batteries were created to offer a maintenance-free option for deep cycle applications. There are two main types of VRLA batteries: absorbed glass mat (AGM) and gel batteries. Each uses a different form of electrolyte; for AGM, a fine boron-silicate mat is soaked in electrolyte to around 95% saturation, and evaporated gases are recaptured to eliminate the need for watering. In gel batteries, sulfuric acid is mixed with a gelling agent to form a thick, almost stiff substance. Neither type of VRLA battery will leak electrolyte if the casing is cracked or punctured, which makes them attractive for applications in which the battery will face rough conditions.
Perhaps the most important consideration when choosing a deep cycle battery is what you intend to use it for. Here are some situations that make a difference in the type of deep cycle battery you choose:
Stationary or Level Equipment
If you’re looking for a deep cycle battery for a vehicle that remains level or a stationary application, a flooded deep cycle battery may be your best bet. Flooded batteries are the most common type of deep cycle battery, and as such they are generally easier to find and more cost-effective than other types of batteries. Because they use a liquid electrolyte, however, they can only be used in an upright position. They should also be used in applications which allow easy access for charging, watering, and other maintenance.
In applications where conditions such as temperature and required power draw vary, a VRLA battery such as an AGM battery may be the best option. Because VRLA batteries are sealed, there is less chance of damage or weathering of the inside components, which helps to ensure a longer lifespan and better performance. VRLA batteries can operate in any orientation, not just upright like flooded batteries, so they’re ideal for situations where they might frequently tip or are installed sideways.
In addition, VRLA batteries may be better suited in situations where regular maintenance is difficult. All deep cycle batteries need to be charged according to manufacturer specifications, so some amount of maintenance is always required, but if you’re not able to water your battery frequently for whatever reason, you should consider buying a VRLA.
This consideration is not just exclusive to deep cycle batteries -- all batteries and applications benefit from a high-quality manufacturing process. But because of their specialized applications and long lifespan, deep cycle batteries can entail a significant investment, which may cause buyers to consider a less expensive, lower quality product. For best performance and return on investment, we strongly recommend higher-quality, more respected brands of deep cycle batteries.
Choosing a deep cycle battery can be a confusing process. Start by understanding the different types of batteries and which are best suited for your intended applications, and you’ll be on the right track. Download our complete guide to deep cycle batteries to learn more: