Marine Batteries

Marine batteries come in three main types:

1. Deep Cycle:

   •  Deep cycle batteries are designed to provide continuous power for long periods of time

   •  Deep cycle batteries are used to power house loads that commonly include navigation aids, fish finders, running lights, radios, and trolling motors

2. Starting: 

   • Starting batteries provide a short, high current burst to crank an engine

3. Dual-Purpose:

   • Dual purpose batteries  can perform both deep cycle and cranking duties

Marine Battery

• The "M" designation means the batteries internal construction is designed for use in a Marine application

• Marine batteries use thicker internal lead plates than an automotive battery, allowing the Marine battery to discharge energy over longer periods of time

• Marine batteries can also be identified by the use the Marine Cranking Amps (MCA)

  • MCA tests are conducted right at freezing (32*F or 0*C) for 30 seconds without falling below 7.2v at the battery MCA rating

NOTE:  Every vessel has different MCA and Amp Hour requirements. To determine the MCA and Amp Hour requirements of a specific vessel, consult the vessel OEM or an authorized Marine Technician.

What is a BCI Number? 

• Commercially manufactured batteries adhere to a sizing standard called the "BCI Group Number", which is established by the The Battery Council International (BCI)

• The BCI number refers to the physical dimensions of the battery

NOTE: If the BCI number is higher on the same type of battery, the Amp Hours may also be rated at a higher level.

Common Marine Battery Group Sizes:  "M" BCI Group # by Length, Width and Height

NOTE:  Measurements in the chart above may change between battery OEM.  Users must ensure they check the exact measurements of the battery they are using.

NOTE:  When selecting a battery, ensure it meets the functional requirements for physical size, post connections, amps, and type of battery.

Lead Acid vs AGM vs Lithium Batteries

• There are several websites on the internet that can be used to inform and help a user decide what the pros and cons are for of each type of battery

NOTE:  Users should be aware and know the exact type of battery charger the vessel is equipped with, because battery chargers are designed to charge up to a certain number of batteries and may not be able to charge AGM or Lithium batteries.