battery chargers

Review Of The Best 4 Bank Onboard Battery Chargers

If you have four batteries on your boat, a four bank charger is a great option. Today’s smart chargers have features that will extend your battery’s life while fully charging your batteries between uses.

The advantages of a modern 4 battery onboard battery charger start with it being hard-wired into your boat at all times. Hardwiring is a great feature because if you purchase maintenance-free batteries, you will have the ability to plug your boat into shore power, and you will be ready for your next fishing trip.

Most modern marine battery chargers control each battery charge cycle independently, allowing the battery to be charged and maintained perfectly between uses. Additionally, the chargers can maintain your batteries over periods of storage during the off-season.

There are many 4 bank marine battery chargers on the market and also non-marine chargers that will do a great job of charging your boat batteries. So, are you ready to find the perfect charger for your boat? Let’s get started with the shortlist then we will go into detail.

Note: most links in this article are Affiliate links, see Affiliate Disclosure, thank you.

A Brief Introduction to 4 Bank Onboard Battery Charger

Onboard Marine Battery Chargers are constructed in a plastic or metal housing (sometimes aluminum). Wire comes through an opening in the housing that is protected by grommets or plastic shielding. Sometimes the wires are sealed from the inside with silicone to prevent water intrusion.

One plug-in wire enters the charger to supply 120 volts (in the US) to the charger. Four wires exit the charger to connect to the batteries and supply 12-volt charging power. Most charger wires have diodes and fuses installed inline. If a fuse is not included inline, it is a best practice to add one rated for your charger’s max output.

 All modern chargers have some form of indicator lights. Most chargers have a separate indicator for each charging cable, so in this case, it should have a minimum of four LED style lights. The more elaborate and more features a charger has, the more LEDs and buttons the charger will have.

Chargers are rated in total amp output and then divided among all batteries. For example, if a 4 bank marine battery charger is rated at 40 amps, that would be divided by four batteries to provide 10 amps for each battery.

Most Onboard marine battery chargers have built-in safety systems. Some of these systems protect from overcharging, reverse polarity, and temperature. Typically, temperature protection is for an overheating battery or charger, but some chargers monitor the ambient temperature to protect lithium batteries in cold weather.

It is very common for boats with 36-volt trolling motors to have 4 bank chargers. Three cables can be used to charge the trolling motor batteries, and the fourth wire can charge the main or starting battery.

Finally, 4 bank marine battery chargers are not budget-friendly no matter how you look at it. The main reason for their high price range is because the charger is like four chargers combined, and the extra effort to make them waterproof.

Check out our article How to Charge Trolling Motor Battery While On Lake

Product Overview

Best buy               

Minn Kota MK 440D marine battery charger

Best high-end (our top choice)      

Minn Kota MK 460 PC Precision On-Board 4-Bank Charger 15-Amp

All Battery Types – Including Lithium

NOCO Genius 4-Bank, 40-Amp Fully-Automatic Smart Marine Charger

Noco Genius GEN4 40 AMP 4 bank smart marine battery charger

The Noco Genius GEN4 is a solid choice for an onboard charger. This unit is a well-sealed poly case that is easy to use. The built-in microprocessor auto-detects the battery type sets the charge profile and does all the safety checks.


  • Can charge Flooded, AGM, Lithium ion, and Gel batteries
  • Waterproof and fully sealed
  • Lightweight and compact
  • Fully automatic
  • 40amp (10 amps each battery)


  • Limited controls

We were very impressed by the Noco Charger’s performance and wished it came in a 60 amp model. The compact size is a huge plus for a small boat.

The ability to charge any type of marine battery is our favorite feature of the Noco charger. Recently all Noco Genius Gen4 chargers were upgraded to include a drop-in lithium battery charge profile selection. Additionally, the manufacturer states that this marine battery charger has added a force mode that will wake up dead lithium ion battery BSMs.

Customer reviews are very good, and it has high ratings on every seller’s website we found. If you like the small form factor, we can support your choice to purchase this marine battery charger.

See customer reviews on

Minn Kota MK 440D marine battery charger

Minn Kota is a leader in trolling motors, and it makes sense for them to make a line of battery chargers to suit every need. The MK 440D Is a tank with a heavy-duty constructed case and thick cables.

The charger has a small footprint, but it is tall. Indicator lights are organized neatly across the top of the unit and are easy to understand.


  • Price
  • Can charge Flooded, AGM, and Gel batteries
  • Waterproof, saltwater tested
  • Vibration and shockproof
  • Automatic multi-stage charging
  • Automatic temperature compensation
  • Easy to understand LED display
  • 40amp (10 amps each battery)
  • Excellent owner’s manual


  • Limited controls
  • Not compatible with Lithium ion batteries
  • Charge times

This is a solid battery charger with few complaints. Minn Kota has great customer support, which I can vouch for. The owner’s manual is the most detailed manual we have seen with instructions and diagrams for every installation. We are hoping that the major brands start including charge profile detection for lithium batteries, but if not, we will need to hope that battery manufacturers can program their BMSs to compensate.

When you install the 440D charger, you will want to position it so you can see the unit’s indicator LEDs.  This charger is fully automatic, so once you connect it, you can forget it. For a boat with 100AH marine batteries or smaller, this unit is the best buy. Additionally, this model performs exceptionally well for flooded lead-acid batteries.

MinnKota is part of Johnson Outdoors inc.

I currently have the MK 220d in my boat, which is a small model, I don’t think they still produce this model. I had an issue, so I gave Johnson Outdoors a call, I told the person what it was doing. They made me pay a deposit and sent me a new charger. I returned the damaged charger, and they refunded my deposit. My warranty was on the edge, and they didn’t say a word, I am a happy customer.

See customer reviews on

Winner!! (top choice)

Minn Kota MK 460PC Precision On-Board 4-Bank Charger 60-Amp

The MK460PC is the best product for the industry-leading Min Kota. Additionally, this charger has a category top charging amps of 60 total, 15 amps per battery. The built-in electronic microprocessor is designed to charge trolling motor batteries.

Versatilely of this charger is industry-leading while still focusing on durability. You will want to mount this model charger where you can get good access in case you change up your deep cycle batteries and get a good view of the indicator LEDs.


  • Can charge Flooded, AGM, and Gel batteries
  • Waterproof, saltwater tested
  • Vibration and shockproof
  • Automatic multi-stage charging
  • Manual battery type settings for each battery
  • Automatic temperature compensation
  • Easy to understand LED display
  • 60amp (15 amps each battery)
  • True-rated output
  • Excellent owner’s manual


  • Price

The MK460PC Precision charger is a full electronically controller charger. One of the main benefits of this charger is that each battery can be manually set to a different charge profile. The owner’s manual has all the directions you will need, and videos are also available.  

Reviews on this product are great. Minn Kota handles all problems professionally. The cost of this charger is the highest on the list, but if you have four batteries on your boat this is a one item solution for all your shore charging needs. Add a Minn Kota MK-3-DC alternator charger to your boat, and you are done building your system.

This charger is not a lithium charger. However, I currently know many people using it to charge their drop-in 12-volt lithium trolling batteries. Use the AGM setting to get the closest charge profile and you should be fine. If your BMS puts your batteries to sleep you will need a different charger or method to wake them up.

MinnKota is part of Johnson Outdoors inc.

Note: I have three chargers on my boat, and if one of those chargers were to fail I would be installing this unit.

See customer reviews on

Guest ChargePro On-Board Battery Charger 40a / 12v – 4 Bank

The Guest On-Board battery chargers have been redesigned to compete with other modern onboard chargers. Their new chargers include leading advancements in digital charging technology and waterproof design/construction.

This model Guest charger has dedicated charging, sensing, and control per bank. The LED status panel for each battery bank provides easy-to-understand information through the charging process.


  • Digital charging technology
  • Fully automatic 5-stage charging
  • LED charge status monitors
  • Waterproof and shock-resistant
  • 12 volt flooded and AGM batteries
  • Built-in safety sensing
  • 40 Amps (10 amps each battery)
  • 2-year warranty


  • Price
  • Not compatible with Lithium batteries
  • Not compatible with Gel batteries

Guest chargers have been a mainstay for entry-level onboard marine chargers for years, but this latest charger has taken their product to the next level. The design of the boat battery charger is straightforward and easy to use.

One drawback of this charger is that it’s only designed for AGM and flooded deep cycle batteries. While that is an issue most commonly used boat batteries are those types. Additionally, with independent bank charge sensing, you should be able to mix both types of batteries.

Because this is a newer model, there is very little customer feedback, but it is a solid company. I can vouch for Guest charges because my first onboard charger was a Guest unit. While I no longer have it installed in my boat it still works great, and in a pinch, I would reuse it without hesitation.

Guest chargers are part of the PowerProducts, LLC marine division.

See customer reviews on

Promariner 36 Amp 52038 Battery Charger Protournament

The Promariner charger is a solid product for serious fishermen. Many professional bass fishermen are using this unit. The top feature to note about this unit is called Distribute-On-Demand. It automatically distributes the charger capacity to the battery that needs the most recharge. If you have a 36-volt trolling motor and your main motor batteries connect to the charger, it can direct 12 amps to each of the trolling motor batteries while the main motor battery doesn’t require a charge.

With the included programming plugs, it is easy to screw in the correct plug and set your charge profile to match your battery type. You will need all the batteries to be of similar battery types for this charger. There are many models of this product available, so be sure to order the correct model to suit your needs.


  • Forced air fan cooling
  • Temperature sensing charge control
  • digital charging technology
  • Fully automatic 5-stage performance charging
  • LED charge status monitor
  • Push-button charge status LED indicators
  • Waterproof and shock-resistant
  • 12 volt flooded and AGM lead-acid batteries
  • Built-in safety sensing for Wiring and battery fault detection
  • 36amp total, distributed as needed
  • 2-year warranty


  • Price
  • charge profile setting is identical for all batteries
  • Not compatible with Lithium batteries
  • Not compatible with Gel batteries

The Promariner charger is a great charger, but you need to be more specific when you purchase this charger and match your needs. Because of that, we recommend this charger for systems that are separate from your main motor because you may want to use a different battery type. Or, if you are using a 24 volt four battery system, you get the most out of this charge, whether they are all one bank or two separate switched banks.

Also, because of the power distribution and ability to deal with temperature we like this charge for hotter climates. Overall customers that purchase the ProTournament 360 Elite Quad charger have good things to say about it and are happy with their purchase.

Promariner chargers are part of the PowerProducts, LLC marine division.

See customer reviews on

24 Volt Battery Chargers – 2 bank / 4 batteries / wired in series

If you are thinking out of the box, here is a thought for your 24 volt systems. Try charging your 24-volt batteries bank with a 24-volt charger. The technical support staff at Samlex told me that I would experience far better battery life out of all my batteries because they would be fully charged and in balance every charge.

I have two great options for 24-volt charges that I am going to share with you.

ProMariner 63170 ProNauticP Series 2420P – 24 Volt, 20 Amp Battery Charger

The ProNautic 2420P Series charger is a professional grade charge designed for larger boats and yachts. The abilities of this charger are almost limitless, but you will find it takes more than average skill to setup.

A certified technician is recommended to hardwire this charger. Then you will need to program in your setting to match your system.


  • Any battery type
  • Digital readout display
  • ProMar Digital Charging Performance – 12 Selectable Profiles
  • Power Factor Correction – Global AC Input
  • Distributed on Demand Technology
  • Digital Self-Calculating Absorption and Battery Health Re-Conditioning Mode
  • Conservation Energy Saver Mode
  • Service and Fault Mode LED Indicators
  • Automatic Fan Speed Control
  • Automatic Temperature Compensation and Built-in Safety
  • 24 volt, 20 Amps
  • price


  • No cables included
  • High level of skill to install
  • Not waterproof

First, this charger is meant for larger boats and to be installed by a professional AYBC certified installer. The owner’s manual is very clear and can walk anyone with technical skills through the install process step by step.

Because the charger is not waterproof, you will need to find a place to install it that is both dry and ventilated. They make an optional remote panel that is water-resistant and can be mounted on a console. The digital readouts are amazing and are carried through to the remote-control panel.

The Amp rating is deceptive because people forget that 12 volts at 40 amps are equal to 24 volts at 20 amps. With all the advanced preprogrammed charging profiles and the ability to manually set it you can adjust the ProNautic 2420P Series charger to any 24-volt system.

Finally, this charger is not expensive, but installation and wiring can add up fast.

Promariner chargers are part of the PowerProducts, LLC marine division.

See customer reviews on

Samlex 40A Battery Charger – 24V – 2-Bank – 3-Stage

The Samlex is the most powerful charger on the list. This 3 stage battery charger can put 20 amps per bank on a two bank battery system. The amount of power this charger delivers is equal to a 12 volt 80 amp charger.

For that kind of charge rate, you need to have strong batteries. In my case, I have Trojan 1275s (150ah/flooded). You can also run it in half mode for smaller batteries.


  • Works for Flooded, AGM or Gel Cell batteries
  • Can be used as a power supply with a battery
  • User Selectable for 2 or 3 stage
  • “Half Power Mode” for safe charging of lower capacity batteries
  • Voltmeter and Ammeter for monitoring
  • Fan cooled
  • Includes temperature sensor
  • 24 volt / 40 Amps (high power)


  • Does not have a digital readout
  • Large size
  • Not waterproof
  • Cost – most expensive

If you need a lot of reliable power, Samlex is the choice for you, but bring your wallet. The Samlex charger has a set of Dip switches on the side to set the different modes. The directions are very clear on how the change the switches to meet your needs.

You must ventilate the Samlex charger, or it will overheat and shut down. Also, most battery manufacturers recommend that your charge rate(in amps) not go above 20% of the battery’s AH capacity. Ex. 100ah battery max is 20 amps max, but I prefer 15% to be safe and still get my batteries recharged fast.  You can easily change the charger to half-power if needed.

Finally, the Samlex charger is not waterproof in any way, because it is not a boat battery charger, so you must take extra care to keep it dry. I have found no complaints about the Samlex chargers, and as an owner of one, I can personally say the Samlex chargers are built like a tank. And their phone support was great before and after my purchase.  

See customer reviews on

Budget-friendly option

If you are on a budget, fish from the shore, lol, just kidding. Buy a Vmax 15 Amp 8 stage charger and charge your batteries one at a time. Charging your batteries individually is going to be a lot of work but it will save you a lot of money.

See customer reviews on

The Vmax 15 Amp 8 stage charger is a great product. I have two of the previous models, and I use them to disulfate and recondition my batteries. Purchase three extra charge wires, and you can hardwire each battery. Then you can plug each battery in until it has completed charging.

Unfortunately, the Vmax charger is not lithium battery compatible. There are many budget-friendly chargers available for lithium batteries.

Click here to read our review of Trolling Motor Batteries


We have given you the basic information on some great chargers. Overall most of the top marine chargers on the market today are of good quality. It is our opinion that it will come down to what your need is. Our overall top pick for a four-bank charger is the Minn Kota MK 460 PC Precision On-Board 4-Bank Charger 60-Amp because of its total amps and versatility.

I hope this helps you design your system for more information check out our articles below.

All You Need to Know About Circuit Breakers for Your Electric Trolling Motor

How do I choose the proper size batteries for my electric trolling motor?

What type of battery should I use for my electric trolling motor?


How do I pick the right size marine 4 bank charger for my boat?

The ideal size 4 bank battery charger will charge your batteries overnight so you can fish the next day. For instance: if you have 100 AH AGM batteries that can be discharged to 50%, 50 amps. A 40 amp 4 bank battery charger charges 10 amps per bank however will balance 5 amps for a 100% charge through all cycles.

If you plan on fishing once per week, you can utilize a smaller sized battery charger such as a 20 amp 4 bank battery charger. You can use a bigger battery charger for lithium batteries however ensure it is compatible.

What does a battery’s amp-hour rating (capacity) mean?

A battery’s Amp-hour ranking is the number of ampere-hours that could be provided per hour throughout a defined time in test conditions. A lot of Deep cycle battery producers label their batteries with a 20-hour rate. For instance: 5 amps for 20 hours = 100 ah at the 20-hour rate. 100 ah batteries are a standard size for flooded or AGM trolling motor batteries.

What is a 4 bank charger?

A 4 bank charger is usually a battery charger that can charge four 12-volt batteries or four banks of 12-volt batteries. These battery chargers have one input power wire, usually 120-volts A/C, and four 12-volt output wires. Each output wire is generally linked to one 12-volt battery or group (bank) of batteries with a total voltage of 12-volts.

Does a 4 bank battery charge work with different battery types?

Many 4 bank battery chargers work with numerous battery types, but check the handbook before purchasing. As a general rule, the smarter chargers will notice the battery type and change the charge profile to match. Other chargers will have a battery choice option in the form of a button, dip switches, and circuit selector inserts.

If you utilize lithium batteries, you can set your battery charger to AGM and get roughly 93% capability out of your battery. However, if you want 100% capability or require to wake your battery up, you require a specialized lithium charger.

How do I select the proper amount of banks for my boat’s charging system?

For standard boat systems, you should utilize a charge that has the same quantity of banks as you have 12-volt batteries. If you have a 36-volt trolling motor, normally, you will have 3 batteries for it and one extra battery for your main engine for an overall of four batteries. For this four battery system, you require a 4 bank marine charger.

Can you use 3 batteries on a 4 bank marine charger?

The majority of 4 bank chargers will charge 3 banks just great; nevertheless, it is not a “best practice”. A 4 bank charger is normally 4 battery chargers built inside one housing to save area and share common power input parts. A lot of 4 bank battery chargers have different charge controllers for each output wire. Consult your chargers user manual to find out more.

What is a reasonable budget for a marine 4 bank charger?

Depending on amperage, charging functions, and quality, a marine 4 bank battery charger must range from $200 to $1000. Nevertheless, you can purchase an outstanding battery charger for your boat for around $400 for the average weekend fisherman.

How many hours does it take to recharge your boat batteries?

Your boat’s recharge time depends on many elements, like the charger’s amp rate, battery size, and total discharge. For instance: if your batteries are 100 AH, you used 50 amps each, you have a 40 amp battery charger, and your optimum charge will be 10 amps per battery, leading to 5 hours to charge 50 amps.

Nevertheless, it will take you longer to get a 100% charge because after your batteries reach above 90%, the majority of smart battery chargers will change to absorption mode and lower amperage, which could double the charge time to 10 hours.

How many years will a 4 bank marine charge last?

Most 4 bank marine battery chargers will last well over five years. Industry-standard service warranties are moving to 3 years, with some more affordable models still just having a 1-year warranty.

Note: I have a MinnKota D220 that is almost ten years old and a Guest 2 bank 5 amp that I use on my test bench is over 12 years old.

Can you overcharge a marine battery with a 4 bank charger?

You can overcharge a marine battery resulting in damage or even an explosion. However, modern 4 bank smart chargers have built-in safety systems to prevent overcharging by switching to maintenance mode when the battery is fully charged. Look for the phrase “Smart Charger” when selecting your charger.

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