The information required when deciding on the correct marine battery

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8th Oct, 2021

The use of batteries is not confined to land only. It extends to the seas and other water bodies as well. In the present day, most marine transport or vehicle cannot operate without a battery, and this includes a wide variety of boats, ships, and submarines. That is why an entire separate category of batteries exists commonly referred to as marine batteries. Enertec knows that it is important for our distributors and vendors to have the necessary information on their products so that they can guide their customers in making the right purchase decision. That is why today, the relevant details on marine batteries will be covered, highlighting some key factors to assist in making the correct choice.

Overview on Marine Batteries Applications


Marine batteries can be both deep cycle batteries and SLI ( starting lighting ignition)  batteries. It depends on their application and the purpose for which they are being used. One key distinction that marine batteries hold over the standard batteries is their construction. Since, they are designed to be used in a rugged environment with excessive vibration and exposure to water, the necessary design adjustments are made to make sure that the battery can withstand these harsh conditions. Generally, marine batteries can be divided into 3 broad categories. They are

  • Marine Starter Batteries – They are SLI batteries, starting lighting ignition,  which means they are responsible for providing the large magnitude of current required at the time of ignition. Their secondary purpose is to provide power to the electronics and auxiliary requirements. 

  • Marine Deep Cycle Batteries – As the name suggests, they are deep cycle by design.  They provide a steady amount of current over an extended period of time. The main purpose of these batteries is to provide auxiliary  power for the electronics present on the marine transport such as electronic displays, sound system, navigation equipment, electric bilge pumps etc..&nbsp

  • Marine Dual-Purpose Batteries – These are hybrid in the sense that they serve as both starter and auxiliary power batteries. This means that they are capable of fulfilling both of the aforementioned roles. Although they are not as efficient as separate batteries, they are useful in cases where the space is limited and utilizing  two batteries may not be possible.


Enertec are a leading Leisure & Marine battery supplier in South Africa and share their knowledge on best practices for maximum performance of deep cycle marine batteries.


Enertec Marine Batteries offer two solutions in one battery – cranking capability as well as reserve power supply for accessories.>

Enertec has conducted an in-depth analysis of the marine battery market over the years and understands the importance of dual-purpose marine batteries. The dual-purpose batteries offered by Enertec are equally competent in terms of both their cranking capability and acting as power source. They possess specifically designed terminals for each of these roles. There are tapered lead terminals to which the cranking cables are attached and threaded terminals to which the auxiliary power cables are connected

. The thick plates used in the design of these batteries ensure that it can perform both roles properly. The Enertec dual purpose batteries have a great track record as they have been tried and tested in the tough conditions of South Africa for over 40 years.

Specific Marine Batteries from Enertec


Apart from a general know-how of marine batteries, understanding the technical specifications and unique features of a battery is relevant when considering the correct marine battery. One must have a clear understanding of the  requirements in terms of voltage rating (V) and Ampere-hour (Ah) rating. With Ah rating, current requirements and the time duration of usage need to be considered. For instance, if a battery has a rating of 100 Ah and the load in the marine transport would require 25 A then the battery would theoretically (ignoring inefficiencies) last 4 hours before requiring a recharge. Similar basic calculations can help in understanding the exact needs from a marine battery. This would of course be a 100% discharge and so the cyclic ability of the battery would need to be considered. 

For the benefit of understanding things further, a few products offered by Enertec are discussed below. They are some of the most high-quality marine batteries available in the market and are worth due consideration. 

  • Enertec DEEP CYCLE range – These batteries such as the M24 (12volt 80 ah), M27 ( 12volt 90ah), 674D ( 12volt 105ah) are the most common batteries used in these applications. They are sealed wet acid batteries by composition and fulfill their role as reasonably priced, good performance batteries that have been successfully used in these applications for the past forty years 


  • Discover Dry Cell Traction series – This selection of batteries which includes models such as EVU1A-A, EV512A-70, EV24A-A, EV27A-A, EV12A-A, are capable options for marine use. They are maintenance free sealed batteries with a host of useful features. With a higher density active material paste, these batteries are capable of providing high discharge current for longer duration. They are ideal for use in marine conditions. This is testified by various quality certifications that confirm the safety of these batteries.


  • Discover Advanced Energy (AES) batteries – They are lithium-ion batteries and come with various benefits as result of its modern technology. They have greater efficiency and better charge times. Their weight is 1/3 of their lead-acid counterpart which adds to their suitability for use as a marine battery.  Other Enertec Lithium-Ion batteries incorporate “drop-in” replacement capabilities 

Marine & Leisure Battery Maintenance


 Ensure that the battery tray is properly installed to avoid damage to the battery in rough waters.

  • Regularly monitoring charge levels of the battery to observe any unusual discharge or loss of capacity.

  • Checking battery terminals for any rust or corrosion 

  • Keeping the battery connected to a smart charger during periods of non-use so that it remains fully charged.

  • If the battery is not to be used for longer durations, and cannot be left connected to an intelligent battery charger, fully charge the battery then disconnect it and store it properly in a cool dry place. 

For any extra information needed on Marine & Leisure Batteries, feel free to contact us or submit an enquiry on our Frequently Asked Questions page, and we will gladly assist.