Marine batteries are different from car batteries. These batteries have heavier plates and a stronger construction that allows them to withstand vibrations and any risk of damage they may experience onboard a motorboat. You will find these batteries more expensive. You need a good charger to ensure you get your battery up, but without damaging it.
If your boat has two batteries and you need to charge them simultaneously, you need a 2 bank battery charger. There are tens of charger brands, and it may be challenging for you to pick the best for your battery. Before you make a poor decision, read my guide on the best chargers.
What Does 2 Bank Battery Charger Mean?
The number of banks refers to the number of batteries a charger should charge. In the case of a 2 bank charger, the charger can charge two batteries simultaneously. If you have one battery, you need a single bank charger. You will need a 3 bank charger if you have two 12V trolling batteries and one 12V battery.
In some instances, the word “bank” might refer to several batteries connected together to work as one larger battery. The smart chargers allow only one output per bank.
How Does A 2 Bank Battery Charger Work?
A two bank charger has two outputs, each with its own terminal connections. There are also microprocessors for each bank. With the output and microprocessors, the charger can handle different battery types, battery sizes, and states of charges. The size of the battery charger will determine the size of the battery you can charge.
Should I Charge My Battery at 2 or 10 Amps?
The charger size refers to the capability of a battery charger; that is, its voltage and amp rating. The amp rating determines how fast the charger can get your battery to the needed capacity while the voltage determines whether the charger’s capability matches your boat batteries’ wiring.
You need to pick the highest amp rating possible to charge the batteries fast. For the voltage, you need to ensure that the voltage rating on the charger and on the battery matches. If that doesn’t happen, the charger will not work. Most boats have a 12V battery, and they may have two or more of these. If your boat has two batteries, you will increase the battery amperage without increasing the voltage of the battery. These two batteries need to be wired parallel.
When wired parallel, the output will still be 12V, so you need a 12V charger. If the batteries are wired in series, the output is 24V, and you need a more powerful charger. If you use a 24V charger on a 12V battery, it will not charge faster. Instead, it will damage your battery and can even cause a fire in your boat.
Should I leave my boat battery charger on all the time? No. Overcharging and undercharging a battery are two of the main ways to damage your boat’s battery. You need to charge just enough.
What Type of Battery Does Your Boat Have?
Before you pick a battery charger from my recommendations below, you need to understand the type of battery your boat has. Most smart chargers are universal and can charge several types if batteries except gel batteries. However, there are some chargers designed for specific types of batteries only.
There are three main types of batteries based on the chemicals in them:
• Wet Cell
• AGM Batteries
A wet-cell battery is also known as a flooded lead-acid battery. It is a traditional battery that has lead plates and an acid solution in its systems. The acid reacts with the lead plates to generate power. The battery should be in a ventilated part of your boat, and you need to top it up with distilled water. Wet-cell batteries are inexpensive, and they can handle overcharging better than other batteries. Chargers for wet-cell batteries need to have an equalization mode to remove sulfate buildup on the plates.
Gel Cell Batteries are an advancement of the wet-cell battery. The battery is sealed and, therefore needs no maintenance. Inside the battery is a thickened electrolyte fluid. This battery operates under pressure where the pressure forces gases in the battery to mix into the water. This battery has two main challenges; overcharging and overheating.
AGM (Absorbed Gas Mat) batteries combine the gel cell and the wet cell batteries. However, they include a lead plate separator that ensures the battery generates consistent power. The glass fiber sheets separator soaks in electrolyte fluid so that it is always next to the battery plates so that it produces power constantly and recharges efficiently.
AGM batteries do not handle overcharging well. If you overcharge, the acid in the battery boils and damages the lead plates. If you have AGM and gel cell batteries, you need special chargers to ensure the batteries do not overcharge and damage the lead plates.
My 2 Bank Charger Recommendations
Battery Charger Name Amperage per bank Voltage AC Input Voltage Charging Stages Batteries charged
- Dual Pro Professional Series 2 15A 12/24 Volts DC 115 VAC/ 60Hz 4 Wet cell, AGM, Gel cell on special order
- Minn Kota Precision On-Board Charger 15A 12/24 Volts DC 120 VAC/ 60Hz 3 (extra two for wet cell battery) Wet cell, AGM, gel cell
- ProMariner 44012 ProSportHD 12 12A 12/24 Volts DC 120 VAC (± 10%/ 50-60Hz 5 Wet cell, AGM, gel cell
- Guest ChargePro 10/10 10A 12/24 Volts DC 90-135 VAC, 50/60Hz 5 Wet cell, AGM
Dual Pro Professional Series 2 – Best Smart Charger
The Dual Pro Professional Series 2 is a smart charger designed to protect your AGM battery from overcharging. What makes this battery charger outstanding is the fact that more than 50 boat manufacturers have it as their first choice. It offers fast charging with a rating of 15 Amps.
It works with 12/24V DC batteries. These should be either AGM or wet cell batteries. If you have gel cell batteries, you can make a special order for a charger that works with the batteries. Dual Pro Professional Series 2 works in fresh or salty water and on land. It can charge group 31 or larger trolling motor batteries.
This waterproof charger uses DeltaVolt smart charging where the chargers have advanced microprocessors for intuitive charging. It offers automatic charging on a variety of battery sizes. You never have to guess when to charge and when to disconnect as it works automatically.
• IP68 waterproof rating
• Intuitive charging technology gets the guesswork out of the way
• Built-in safety features
• Fast charging
• It is relatively heavy
• The cords are short
Minn Kota Precision On-Board Charger – Best for All Types of Batteries
With 15 amps per bank, same as the Dual Pro Professional Series 2, you can expect fast charging times. Minn Kota has made a name for themselves with products such as shallow water anchors, trolling motors, and precision chargers.
Minn Kota created this charger such that each bank is isolated. This way, you can charge different sizes and types of batteries at the same time. If you have a gel cell and a wet cell battery, you can charge them simultaneously. It can charge these batteries on series or parallel connections or as independent batteries.
The battery can sense and compensate for outdoor temperatures. This ensures that the lead plates do not sustain damages from extreme ambient temperatures. Better yet, the charger can adjust for low line voltage issues. If the outlet has several other devices that need power, the charger may not get the full 120V. The charger adjusts to ensure that the battery charges consistently.
Further, the charger an equalization mode that ensures wet cell batteries do not have a buildup of sulfates.
• Charges extremely fast
• Can charge different battery types simultaneously
• Adjusts to protect the battery against extreme ambient temperatures
• Charger might overheat a little
ProMariner 44012 ProSportHD 12 – Best Lightweight Battery Charger
The ProMariner 44012 ProSportHD 12 is an advancement of the ProSport 12. It is a heavy duty and fast-charging charger that works with either 12V or 24V batteries. The 12-amp charger employs Distributed On-Demand Charging Technology with advanced microprocessor technology. The battery uses five automatic charge stages, which include analyzing, charging, conditioning, energy saving, and equalization for wet cell batteries.
The charger features a tri-surface heat sink construction that enhances fast charging and cools it fast. Further, the charger delivers constant current charging at all times.
One of my favorite features on this charger is the new dashboard with LED lights and gauges. This dashboard shows completion status, battery status, and system check among others. It also has some built-in safety features that are really interesting.
• Works great for small boats
• It is a lightweight option
• Advanced built-in safety features
• Simple and color-rich display
• You need to select the battery type every time you plug in the charger
Guest ChargePro 10/10 – Best Easy-To-Use Charger
If you want a simple to use charger, the Guest Charge Pro might be a great choice for you. The battery charger received an upgrade in 2020, making it even better at charging. It features a flange-less body with an aluminum casing that makes it durable. The manufacturer uses sealed gaskets to give the charger 1P67 waterproof quality. The resulting charger is shock resistant, and it works well on salt and freshwater.
Although the manufacturer added several materials, the battery is 40% lighter than its predecessors. On the charger are simple lights that show the status of the battery.
Every charger features individual dedicated charging and sensing for each bank. This way, you can charge different types of batteries simultaneously. It charges a battery in five stages from analyzing, pre-charging, charging, conditioning, and energy saving.
Like the ProMariner 44012 ProSportHD 12, this battery also has built-in security features to protect it.
• Easy to install and use
• Enhanced thermal management
• Very lightweight
• Excellent exterior construction for durability
• Doesn’t charge gel cell batteries
It should be easy for you to pick a good charger once you read my guide above. Besides the voltage and amperage, other factors you need to consider include multi-stage charging, waterproof construction, vibration resistant, safety features.
Go on and get a charger that meets your needs.