How To Choose the right battery
To Choose the right battery
Many consumers, and even experts in the marine industry, are unaware of the different batteries and technologies that are available to power their boats. Whether a recreational boater, professional angler, competitive sailor or someone in between, different applications have different electrical needs, which present specific demands on a battery. Knowing more about marine batteries and their technologies can save boaters time, maintenance costs and headaches due to performance issues.
Marine Battery Basics
Lead-acid batteries are used in nearly all marine applications. The basic chemical reaction in lead-acid batteries is essentially the same across all technologies. Electrolyte (acid) reacts with lead creating an electrical current that is conveyed to a negative and positive terminal from which a boat’s electrical system draws power. Differences in battery composition, however, result in different power delivery, whether for turning engines over or powering demanding electrical systems. Starting and deep cycle batteries are designed differently, tailored to deliver high power in short bursts or consistent energy over longer durations.
The lead plate material has alloys added to increase strength and stiffness to prevent the positive and negative plates from contacting each other and triggering internal short circuits. The addition of alloys reduces the battery’s overall ability to accept an electrical charge. As the plates go through repeated cycling, byproducts of the chemical process are shed from the plate surfaces. This cast-off material may pile up on the floor of the battery – high enough, in fact, to create short circuits and reduce battery power.
Some wet-cell batteries are designed to be maintenance-free; these are usually used in starting, ignition, and chassis-lighting systems. The larger, deep-cycle batteries used for house power generally require the electrolyte to be maintained at the proper level. Repeated cycling of the batteries produces a loss of electrolyte from gassing and misting during recharge.
A deep cycle marine battery should be used in an application that will typically discharge 25% or more of the battery capacity. Deep cycle batteries have thicker lead plates and/or more dense active material to withstand numerous discharge and recharge cycles. Deep cycle batteries should be used in high-accessory boats or high cycling applications (i.e. boats with advanced fish-finding and GPS navigation systems, a trolling motor, radio communications, bilge pumps, various lights, etc.).
Starting batteries have thinner lead plates and/or lower density active material, designed to deliver maximum power for a short duration.
Starting a boat typically discharges a starting battery only 1% to 3%. When used in a deep cycle application, like powering a demanding boat electrical system, the starting battery’s life will be shortened proportionally to how deeply it is cycled on a regular basis.
Installations - to add a second deep cycle battery for additional pow