Boat Battery Chargers: Features and Specs

Boat battery chargers can be confusing to choose.  There are so many types and so many specifications.  This article separates the features and specifications to help you make a better choice.

Here are the most important considerations when choosing boat battery chargers:

#1 – Charger Environment

boat battery chargers wet environment

Moisture and Boat Battery Chargers

If your boat is open and exposed to the elements, you should choose a charger with a waterproof housing.  When considering waterproofing, a specification to look for is ingress protection rating.  An ingress protection rating of IP68 would be totally dust tight and provide protection against prolonged effects of immersion in water under pressure.  These units are usually fully sealed, safe to store onboard year round, and can be permanently left in a damp environment.  They may be described as fully potted which means that the electronics are encapsulated in resin.

Your boat application may not require a waterproof housing.  If your boat is large with an enclosed cabin, where you can insure no direct contact with water, you may choose a battery charger that is not waterproof.

vibration environment for battery chargers for boats

Boat Battery Chargers Vibration

If your battery’s environment experiences prolonged, significant vibration, you should look for a vibration proof specification for the any battery charger you are considering.  Vibration can be handled through a rugged case or through vibration dampening materials used in construction.

hot environment for marine battery chargers


If your environment experiences frequent or severe temperature changes, you should choose a battery charger that compensates for temperature changes.  This is important to insure the proper charging and maintenance of your battery.


#2 – Boat Battery Charger Output

Charger output can be described in two ways; amps and banks.

The amps or power output of the charger should again be determined by applications.

  1. Low Output – (6 amps or below) A low output charger may be applicable for maintenance use or any low amp hour battery application.
  2. Medium Output – (9 – 15 amps) A medium output charger would be applicable for medium use or occasional use perhaps only on weekends for a trolling motor.
  3. High Output – (15 amps or above) 1) A high output charger would be used in high amp hour battery applications (150 ah for example), or any situation where repeated rapid rechargers are called for.

Banks (physical outputs) determine how many batteries can be charged simultaneously by the battery charger.  Single banks are used for a single battery while multiple banks can be used to charge and maintain 2, 3 or more batteries simultaneously.  A key specification for multiple bank chargers is whether it has independent outputs (a separate positive and negative connection per bank) and each bank has its own microprocessor to control charging.  Independent outputs allow batteries of different size, type, and charge status to be connected simultaneously to the same boat battery charger.


marine battery charger chemistry

#3 – Battery Chemistry

Batteries used in marine applications may be more likely to be deep cycle, flooded, Gel Cel or AGM.  It’s important to determine your battery’s chemistry and carefully select a battery charger that supports that chemistry.  Particularly in the case of Gel Cel batteries, it’s important to make sure your battery charger is a true gel cel charger.  Some boat battery chargers that claim to be gel cel chargers are only AGM or deep cycle.

boar battery chargers ignition protection

#4 – Ignition Protection

Because of the enclosed nature of some boat engine and battery locations, it’s important that you check for an ignition protection feature.  Ignition protection keeps sparks out when starting the engine preventing the ignition of surrounding flammable gases.  Check for compliance with ISO 8846 and U.S. Coast Guard Title 33 CFR 183.410 ignition protection specifications.  These specifications insure:

  1. the device will not ignite a flammable hydrocarbon mixture surrounding the device when and ignition source causes an internal explosion
  2. or is not capable of releasing sufficient electrical or thermal energy to ignite a hydrocarbon mixture
  3. or the source of the ignition if hermetically sealed.


power supply for marine battery chargers

#5 – Power Supply

Some battery chargers can provide power inversion to allow them to be used to power AC devices on your boat.  They can also provide converted voltage to charge various DC devices.  If that is important to you, make sure you choose a boat battery charger with this capability.


marine battery chargers onboard

#6 – Onboard

Onboard battery chargers can be mounted to your boat permanently using a bracket.  This makes them immediately accessible each time you need to charge your battery and is more convenient for leaving the battery charger in maintenance mode fulltime.


#7 – Starting

Some boat battery chargers can also provide enough amperage for starting in the case where your battery is too weak to start the engine of your boat.  If you need that capability, be sure your battery charger choice has starting amperage.

marine battery chargers warranty

#8 – Warranty

All other features and specifications being equal, choose the best warranty you can find.  It is not uncommon for battery chargers to fail, particularly in marine environments.  Make sure your manufacturer backs its equipment with a solid warranty.  A two plus year warrant should be expected.


Marine Battery Charger Comparison

TitleSchumacher SSC-1500A Ship 'n Shore SpeedCharge Charger with included battery clampsNOCO Genius GEN2 12V+12V 2-Bank 20 Amp Smart On-Board Waterproof Battery ChargerSchumacher SE-1-12S Fully Automatic Onboard Battery Charger - 1.5 AmpsBattery Tender 800 Waterproof 12V Battery ChargerBattery Tender 022-0165-DL-WH 12-Volt 2-Bank Battery Management SystemBattery Tender 022-0157-1 Waterproof 12 Volt Power Tender Plus Battery Charger
FeatureDigital meter displays battery charge status and test results
Features retractable handle for easy portability
System test helps diagnose problems
Electronic push-button control switches help select between display mode, charge rate, or battery
Accommodates 12-volt batteries only; Clamps are rated @ 75 Amps
20 Amperes (10 Amperes per bank) Smart On-Board Battery Charger for 12-volt batteries; charges and maintains all types of lead-acid batteries from 25-230Ah, including Wet, Gel, MF, and AGM
Designed for safety; safe for anyone to use; does not generate sparks, and protects against reverse battery hookup, short circuit, open circuit, overheat, overcurrent and does not overcharge the battery
100 percent waterproof; completely sealed to protect against the most extreme environments and rated at IP68
Rapid Charging Technology; Charges batteries 2X faster than traditional battery chargers, and a lightweight, compact design
The most advanced charger ever; it features innovative and advanced technology that makes charging easy and simple; the charger makes important charging decisions so you don't have to. It is the safest, most effective charger you may ever use
1.5-amp charger
Has reverse polarity protection
Molded with plastic weather proof case
Plugs into an electrical wall outlet
Can install next to the battery on automobiles, boats, tractors, golf carts, and other equipment
Spark proof and reverse polarity protected; protected by a 3-year limited warranty
Designed for use on all AGM sealed maintenance free, lead calcium, and flooded batteries
100% waterproof and ultraportable at a size not bigger than a computer mouse
Complete 3-step charging program (initialization, bulk charge, and float mode) for maintaining optimal performance levels without over charging
Automatically switches to float/maintenance voltage after fully charging the battery
Solid state two color LED indicates stage of charger; spark proof and reverse polarity protected
Two independent charging stations, each providing 12 volts/1.25 amps, with temperature compensation to ensure optimum charge voltage according to ambient temperature
Complete 3-step charging program (Initialization, Bulk Charge, Float Mode) allows for optimization of battery power, without overcharging
Perfect for all AGM (absorbed glass mat), sealed maintenance free and flooded batteries
2-year limited warranty
Fully mountable
Vibration resistant
Steel casing for extra strength and works at 5 ampere
Completely safe SC and RP protected
2 year warranty
Warranty5 year limited warranty3 Year Limited Warranty2 year limited warranty3 year material and workmanship2 year material and workmanshipTwo (2) Year Warranty
Weight4.83 pound7 pound0.25 pound3.2 pound3.3 pound4.4 pound
Width12 inch9 inch8 inch4 inch10.5 inch11.3 inch
Length4 inch10.2 inch2 inch10 inch11.6 inch11.6 inch
Rating4.2 out of 5 stars4.3 out of 5 stars4.3 out of 5 stars4.6 out of 5 stars4.8 out of 5 stars4.6 out of 5 stars
ReviewsRead ReviewsRead ReviewsRead ReviewsRead ReviewsRead ReviewsRead Reviews
LinkMore InfoMore InfoMore InfoMore InfoMore InfoMore Info

Product prices and availability are accurate as of Jul 8 2:40:09 UTC but are subject to change. Any price and availability information displayed on the merchant site at the time of purchase will apply to the purchase of this product.

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I have covered some of the often confusing features and specifications of boat battery chargers.  Hopefully they are no longer confusing.  I hope this article is useful to you as you choose your one of the many boat battery chargers available!

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