Marine batteries are an essential element for autonomy at sea. They can also affect the engine’s operation, instruments, navigation lights, and many other elements.
Marine batteries are not all the same.
There are four different types of deep cycle marine battery. Lead-acid batteries, gel batteries, AGM batteries, and lithium batteries. Each type of battery used for the boat has specific characteristics and presents substantial differences.
Marine battery with Lead-acid
The battery for the Lead-acid boat is immersed in sulfuric acid, which acts as an electrolyte. This type of technology needs air recirculation as it produces easily flammable gases. The Lead-acid marine batteries can only be installed horizontally to avoid the escape of sulfuric acid. This type of battery requires periodic checking of the electrolyte level and topping up with distilled water when the level drops below the minimum.
Nautical gel battery
In the case of marine gel batteries, however, the electrolyte is immersed in a gelatinous substance. These batteries are sealed to prevent gases from escaping. The marine gel battery is also installed inside the passenger compartment, not necessarily horizontally. Furthermore, it does not require maintenance and can withstand deep discharges and many charge-discharge cycles without any problems.
AGM marine battery
In AGM marine batteries, unlike other types, the electrolyte is found inside spongy fiberglass elements. The installation of batteries for AGM boats is many: being sealed, they do not require any maintenance, they do not exhale harmful gases, they do not allow the electrolyte to escape even in difficult conditions, and therefore can easily be installed anywhere.
In addition, they have superior qualities compared to other types of marine batteries. They have greater robustness, longer lifespan, shorter charging time, and a low self-discharge rate when not used for a long time (around 3% per month). An AGM boat battery guarantees operation in almost any position, has excellent resistance to vibrations and is not very sensitive to temperature changes.
Nautical lithium battery
Deep-cycle lithium marine batteries are the latest on the market. They have all the typical characteristics of lithium batteries, such as very low weight, high energy density, the possibility of providing large currents, numerous charge cycles, and, particularly, of considerable importance, they do not require any maintenance. A disadvantage of this product is certainly the price, still significantly higher than lead-acid batteries, and the degree of safety, which is lower than that guaranteed by lead-acid batteries.

How to safeguard marine batteries
After illustrating the characteristics of the various types of marine batteries and understanding the obvious advantages of AGM marine batteries, let’s find out how to prevent their deterioration.
A battery can deteriorate in several ways: due to a loss of mass or corrosion.
For example, intensive discharging and recharging of a boat battery can cause wear of the active material, which over time contributes to undermining its functioning.
Similarly, when the voltage of a marine battery is high, corrosion can occur at the end of the charge cycle. This can lead to the degradation of the positive plaques.
To minimize damage, it is possible to use battery chargers with different charge cycles and store the marine batteries in a cool and ventilated place, always paying attention to the lubrication of the terminals.
The marine battery for sale on Renogy is an essential nautical accessory on every boat, used for various purposes, from starting the engine to powering the electrical or electronic equipment on board. The marine batteries dedicated to starting the boat engine, also called starter batteries, must deliver high power quickly. In contrast, those used to power the onboard equipment have lower instantaneous power but can deliver energy for longer.
Choose Nautical Batteries
Those who own small boats and must maximize the space available can opt for hybrid-type batteries for boats, which do not reach the specific performance of dedicated batteries but are still able to guarantee an acceptable level of performance both for engine starting and for onboard services. In our online shop, you will find all boat batteries, from common liquid electrolyte batteries to gel batteries to AGM RV batteries. All watertight and maintenance-free marine batteries are available in the different amperages necessary to guarantee the right power and capacity for every need, from small boats to large yachts. Multiple offers will allow you to choose the most suitable marine battery for your boat with maximum savings.