3-Bank Onboard Marine Charger: 6 Best Rated For 2020

closeup photo of a noco 3-bank onboard marine charger

Outdoors Informed is reader supported. We independently research and rate every product. When you buy through a link on our site, we may earn an affiliate commission. However, our opinions and evaluations are our own. Outdoors Informed does not accept free products from manufacturers. Learn more

For this article I will assume that your boat uses three separate 12 volt batteries onboard. One cranking battery to start a motor and two deep cycle batteries for other uses (trolling, etc). By choosing a 3-bank onboard marine charger you can charge all three 12 volt batteries at the same time.

I understand, buying boat electronics is daunting, which part works best with another? Having the right information is important for picking marine batteries and chargers. Extending a marine battery’s performance depends on the battery type, its use and how you charge it. For these reasons it’s crucial to have the right charger, one that is best suited to your needs.

As you read, I pick and review chargers to meet your needs from a leading marine charger manufacturer. Including Dual Pro, Minn Kota, NOCO Genius, Guest, and ProMariner. After the reviews, is a frequently asked questions section about 3-bank marine chargers.

If you want to read the whole article, I include a comprehensive comparison table below. Also for simple use there is a handy table of contents that you can click to travel to a specific review or section. Okay, let’s get started.

We updated this article in January 2020 to ensure the 3-bank smart chargers we recommend meet current standards. For this year two new models hit our best of list, one from the Promariner and another from the Guest brand. Read on to discover the best 3-bank marine battery chargers for 2020. 

Share This Article:
Share on facebook
Share on twitter
Share on reddit

Table of Contents

Comparison Chart

Preview
Editors Choice
Dual Pro 15 Amp/Bank Professional Series 3 Bank Charger
MinnKota MK 330D On-Board Battery Charger (3 Banks, 10 Amps per Bank)
Top Marks
ProMariner 63120 ProNauticP Series 1220P - 12 Volt, 20 Amp Battery Charger
Product Name
Dual Pro PS3
Minn Kota MK330D
ProMariner ProNauticP 1220P
Verdict
Only Repairable Charger!
Popular & Reliable Digital Charger
Impressive Tech & Super Lightweight
Amps Per Bank (Total Amps)
15 (45)
10 (30)
Variable (20)
Battery Capacity – Amp Hours
Up to 130 AH Per Bank
40-130 AH
100-200 AH
DC System Voltage
12/24/36 V
12/24 V
12 V
AC Input
115 VAC / 60 Hz
95-135 VAC / 60 Hz
100-240 VAC Auto-ranging, 50-60 Hz
Battery Types
Wet Cell, AGM & Gel (custom order)
Wet Cell, AGM
Wet Cell, AGM, GEL, LifePO4/Lithium and Custom Calcium
Size (L X W X H) Inches
13″ x 8.25″ x 6″
16.25″ x 7.5″ x 4″
10.25” x 8.5” x 3.5”
Weight – Pounds
22.50 Lbs
20 Lbs
5 Lbs
Cable Lengths – Feet
3′ AC & 5′ DC
6′ AC & DC
6’ AC & DC
Warranty – Years
3
3
5
Editors Choice
Preview
Dual Pro 15 Amp/Bank Professional Series 3 Bank Charger
Product Name
Dual Pro PS3
Verdict
Only Repairable Charger!
Amps Per Bank (Total Amps)
15 (45)
Battery Capacity – Amp Hours
Up to 130 AH Per Bank
DC System Voltage
12/24/36 V
AC Input
115 VAC / 60 Hz
Battery Types
Wet Cell, AGM & Gel (custom order)
Size (L X W X H) Inches
13″ x 8.25″ x 6″
Weight – Pounds
22.50 Lbs
Cable Lengths – Feet
3′ AC & 5′ DC
Warranty – Years
3
Details
Preview
MinnKota MK 330D On-Board Battery Charger (3 Banks, 10 Amps per Bank)
Product Name
Minn Kota MK330D
Verdict
Popular & Reliable Digital Charger
Amps Per Bank (Total Amps)
10 (30)
Battery Capacity – Amp Hours
40-130 AH
DC System Voltage
12/24 V
AC Input
95-135 VAC / 60 Hz
Battery Types
Wet Cell, AGM
Size (L X W X H) Inches
16.25″ x 7.5″ x 4″
Weight – Pounds
20 Lbs
Cable Lengths – Feet
6′ AC & DC
Warranty – Years
3
Details
Top Marks
Preview
ProMariner 63120 ProNauticP Series 1220P - 12 Volt, 20 Amp Battery Charger
Product Name
ProMariner ProNauticP 1220P
Verdict
Impressive Tech & Super Lightweight
Amps Per Bank (Total Amps)
Variable (20)
Battery Capacity – Amp Hours
100-200 AH
DC System Voltage
12 V
AC Input
100-240 VAC Auto-ranging, 50-60 Hz
Battery Types
Wet Cell, AGM, GEL, LifePO4/Lithium and Custom Calcium
Size (L X W X H) Inches
10.25” x 8.5” x 3.5”
Weight – Pounds
5 Lbs
Cable Lengths – Feet
6’ AC & DC
Warranty – Years
5
Details

Preview
Top Marks
ProMariner 44029 ProSportHD 20 Plus Battery Charger-20 Amps / 3 Bank
Guest 2731A ChargePro On-Board Battery Charger 30A / 12V, 3 Bank, 120V Input
Budget Friendly
NOCO Genius GEN3, 3-Bank, 30-Amp (10-Amp Per Bank) Fully-Automatic Smart Marine Charger, 12V Onboard Battery Charger And Battery Maintainer
Product Name
ProMariner ProSportHD 20 Plus
Guest ChargePro 10/10/10
NOCO Genius GEN3
Verdict
Latest Evolution Of ProSport Chargers
Simple 5 Stage Charging
Inexpensive & Popular
Amps Per Bank (Total Amps)
Distributed On Demand (20)
10 (30)
10 (30)
Battery Capacity – Amp Hours
Info Not Available
Info Not Available
Up To 230 AH
DC System Voltage
12/24/36 V
12/24/36 V
12 V
AC Input
120 VAC (+/- 10%) 50/60Hz
90–135V AC 50/60Hz
70-130 VAC, 50-60 Hz
Battery Types
AGM/Wet Cell, Gel, & HP AGM
Wet Cell & AGM
Wet Cell/AGM, Gel, Calcium, & Enhanced Flooded Battery
Size (L X W X H) Inches
7.9 x 12.8 x 2.9
8.7 x 9.0 x 4.1
11.1” x 8.4” x 3.1”
Weight – Pounds
7.8
8
15.1 Lbs
Cable Lengths – Feet
6 AC & 6 DC
6 AC & 6 DC
6.3′ DC & 6′ AC
Warranty – Years
3
2
5
Top Marks
Preview
ProMariner 44029 ProSportHD 20 Plus Battery Charger-20 Amps / 3 Bank
Product Name
ProMariner ProSportHD 20 Plus
Verdict
Latest Evolution Of ProSport Chargers
Amps Per Bank (Total Amps)
Distributed On Demand (20)
Battery Capacity – Amp Hours
Info Not Available
DC System Voltage
12/24/36 V
AC Input
120 VAC (+/- 10%) 50/60Hz
Battery Types
AGM/Wet Cell, Gel, & HP AGM
Size (L X W X H) Inches
7.9 x 12.8 x 2.9
Weight – Pounds
7.8
Cable Lengths – Feet
6 AC & 6 DC
Warranty – Years
3
Preview
Guest 2731A ChargePro On-Board Battery Charger 30A / 12V, 3 Bank, 120V Input
Product Name
Guest ChargePro 10/10/10
Verdict
Simple 5 Stage Charging
Amps Per Bank (Total Amps)
10 (30)
Battery Capacity – Amp Hours
Info Not Available
DC System Voltage
12/24/36 V
AC Input
90–135V AC 50/60Hz
Battery Types
Wet Cell & AGM
Size (L X W X H) Inches
8.7 x 9.0 x 4.1
Weight – Pounds
8
Cable Lengths – Feet
6 AC & 6 DC
Warranty – Years
2
Budget Friendly
Preview
NOCO Genius GEN3, 3-Bank, 30-Amp (10-Amp Per Bank) Fully-Automatic Smart Marine Charger, 12V Onboard Battery Charger And Battery Maintainer
Product Name
NOCO Genius GEN3
Verdict
Inexpensive & Popular
Amps Per Bank (Total Amps)
10 (30)
Battery Capacity – Amp Hours
Up To 230 AH
DC System Voltage
12 V
AC Input
70-130 VAC, 50-60 Hz
Battery Types
Wet Cell/AGM, Gel, Calcium, & Enhanced Flooded Battery
Size (L X W X H) Inches
11.1” x 8.4” x 3.1”
Weight – Pounds
15.1 Lbs
Cable Lengths – Feet
6.3′ DC & 6′ AC
Warranty – Years
5

Best Overall 3-Bank Onboard Marine Charger

Purple label with gold anchor stating Editor's choice
Sale
Dual Pro 15 Amp/Bank Professional Series 3 Bank Charger
  • Made in the USA
  • Battery Chemistry Types: Wet Cell, AGM, and Gel Cell (special order only)
  • Voltage: 12/24/36 Volts DC
  • AC Input Voltage: 115 VAC / 60Hz
  • Battery Capacity: Up To 130 AH Per Bank
  • Amps Per Bank: 15 A
  • Total Amperage: 45 A
  • Charging Stages: 5
  • Dimensions (inch): (L)13 x (W)8.25 x (H)6
  • Weight (lbs): 22.5
  • Water Proof Design Standard: IP68
  • Warranty (years): 3
What We Like
What We Do Not Like

Dual Pro PS3 3-Bank Onboard Marine Charger Review:

The Dual Pro PS3 is my pick for the best 3-bank battery charger in 2020. For over a decade it has set the gold standard for smart boat battery charging. It is the safest, most reliable, and best performing marine battery charger available. In fact over 50 boat manufacturers choose it for their new builds. This USA made marine charger in particular is a top of the line 15 amps per bank smart charger. Infact the Dual Pro PS3 can charge 12 to 36 volt marine batteries in series or parallel.

What separates Dual Pro from other brands is that it’s the only repairable charger on the market! Unlike other brands the PS3 won’t become a new boat anchor like your previous broken charger.

Use it to charge Wet Cell or AGM batteries, or it can be special ordered for gel cell batteries. Concerned about durability? Don’t be, it has the highest waterproof rating possible: an IP 68 rating. This rating indicates that the charger is submersible and hermetically sealed.

Like many of the others, the PS3 comes with all the safety you would expect for a best in class marine battery charger. Such as short circuit, reverse polarity protection and temperature compensation. Boaters love how simple it is to install and easy to use. Due to the easy to read LED charge mode lights and real time diagnostic coding.

DeltaVolt Intuitive Technology

Inside the Dual Pro is the “DeltaVolt” smart charging system. Each bank uses an “Intuitive” microprocessor to provide 5 stage controlled charging. This helps to enhance battery performance and extend the life of batteries too. As well, it adapts to the charging needs for both cranking and deep cycle batteries.

Another bonus is it can charge a mix of battery sizes at the same time. The PS3 is a set it a forget it smart charger – it doesn’t get any easier than that.

Possible Concerns

One thing I don’t like for the PS3 is the power cords are a bit short. Which is a nuisance, if I don’t dock right next to a power source. Another possible deterrent for small boaters is its weight, as it weighs a whopping 22.5 pounds. For small boaters where weight is paramount, you should take a peek at the ProMariner ProNauticP 1220P.

Verdict:

Choose the Dual Pro Professional Series 3 (PS3) if you want the best 3-bank marine charger in 2020. Not only is it a heavy duty powerful charger but it is also safe, reliable and repairable. Plus Dual Pro offers a 3 year warranty too! My only wish is that the AC power cords were the standard six feet long.

Great 3-Bank Charger For Fishing Boats

Sale
MinnKota MK 330D On-Board Battery Charger (3 Banks, 10 Amps per Bank)
  • Made in the USA
  • Battery Chemistry Types: Wet Cell, AGM
  • Voltage: 12/24 Volts DC
  • AC Input Voltage: 95-135 VAC / 60Hz
  • Battery Capacity: 40-130 AH
  • Amps Per Bank: 10 A
  • Total Amperage: 30 A
  • Charging Stages: 3
  • Dimensions (inch): (L)16.25 x (W)7.5 x (H)4
  • Weight (lbs): 20
  • Water Proof Design Standard: IP67
  • Warranty (years): 3
What We Like
What We Do Not Like

Minn Kota MK330D Review:

Let’s take a look at another choice for the best 3-bank onboard charger – the Minn Kota MK330D. This charger is a preferred choice of fishing boats with Minn Kota trolling motors. I like that it is a well priced, premium automatic multi-stage digital charger. The MK330D has 10 amps per bank for a total of 30 amps. With safety features that include overcharge protection by monitoring the voltage and temperature.

The MK330D will recharge Wet cell and AGM batteries in 4 to 6 hours. As a result, the rapid recovery makes this 3-bank marine charger one of the most popular on the market.

Digital MicroProcessors

This boat battery charger uses digital microprocessors to create a quick, safe and correct charge. It has automatic 3 stage charging to detect how much to recover each battery per bank. These include a bulk charge, float charge and a maintenance charge. For ease of use it has a detailed yet simple to read LED display. The LEDs show enhanced charge status codes, maintenance mode status and error notifications.

Plus it has an automatic outside temperature compensation feature. This is great for boats in hot climates since it will prevent overheating and boiling. For waterproofing the charger is epoxy filled which also aids in vibration protection.

Like most premium brands Minn Kota also offers a 3 year warranty for peace of mind.

Downsides of the Minn Kota MK330D

The first thing I don’t like about the MK330D is that it had limited uses for battery types. It only charges traditional Wet cells or standard AGM batteries. If you use many types of battery chemistry this isn’t the charger for you. Second, it’s a big heavy charger, as a result it isn’t suitable for small vessels.

Third, it is a simple 3 stage digital charger which is fine for boats with little electronics. However modern boaters tend to add more electronics which equals complicated charging and the need to use smart multi stage chargers. In this case, if you love this brand, then check out the Minn Kota MK330PC.

Verdict:

If you are looking for a capable mid priced digital charger for Wet cell or AGM batteries this is a great choice. It’s also a great complimentary charger for trolling motors of the same brand. While it does the basics well, it may be limiting for boaters who use multiple battery types onboard.

Best 3-Bank Marine Charger For Sailboats

top marks label in blue with yellow check mark
ProMariner ProNautic 1220P
  • Made in the USA
  • Battery Chemistry Types: Wet Cell, AGM, GEL, LifePO4/Lithium and Calcium (Special Order)
  • Voltage: 12 Volts DC
  • AC Input Voltage: 100-240 Auto-ranging
  • Battery Capacity: 100-200 AH
  • Amps Per Bank: Variable
  • Total Amperage: 20 A
  • Charging Stages: 12 selectable
  • Dimensions (inch): (L)10.25 x (W)8.5 x (H)3.5
  • Weight (lbs): 5
  • Water Proof Design Standard: Info Not Available
  • Warranty (years): 5
What We Like
What We Do Not Like

ProMariner ProNautic 1220P Review

The first time you pick up the ProNautic 1220P you will understand why I am giving this charger top marks for 2020. This boat battery charger is incredibly lightweight and compact. These physical features are big bonuses for sail boaters who worry about weight.

The second reason I give this 3-bank charger top marks is for its innovative technology. The ProNautic provides concise charging by using “ProMar Digital Performance Charging.” I’ll further explain what this technology is later in the review. By using ProMar, it can address the trend of using more 12-volt electronics on our boats. As well, it expands its uses because it charges many battery chemistry types at the same time. Such as Wet Cell, AGM, Gel and even Lithium batteries.

Like other ProMariner chargers, this one uses a variable amount of amps per bank. The amount depends on which bank needs the most amperage at a given time. The total amount of amps for this 3-bank charger is 20 amps.

Three Great Features For Sail Boaters:

One handy feature for sail boaters travelling the world is the “power factor” correction. This is an auto-ranging global AC input with reduced harmonic distortion. Simply put this charger can operate off standard household power connections anywhere in the world.

A second feature I appreciate is the comprehensive real time LED display. These LED indicators show current charge status, wiring faults or adverse conditions. It is amazing how much information is available to the user.

The third feature a boater with Wet cell batteries will love is the automatic conservation mode. This mode lowers float voltage if the unit doesn’t register a load greater than 5 amps over a 72-hour period. Next if your boat is in storage it will de-sulfate batteries every 21 days.

As a bonus feature, it has a cooling fan to prevent the restriction of air flow and reduce overheating.

With the ProNautic 1220P: you can install, set and forget.

ProMar Digital Performance Charging

“ProMar” is a charging technology that provides over 12 different select-able profiles! This charging technology combines digital control with software to provide pinpoint charging abilities. Each profile uses paired charging algorithms to ensure proper battery chemistry. As a result, you get enhanced battery life and performance. Plus it allows you to power dockside loads like lights and 12 volt appliances as well.

The 1220P then combines this “ProMar” with Distributed On Demand™ technology. This senses and adjusts to individual battery bank charging needs. If one bank it nearly dead and another is almost full, it will give most of the voltage to the near empty bank.

This combination provides controlled charging that delivers cooler operation and faster efficient charging.

Downsides of the ProMariner ProNautic 1220P

Like last year, I found two main downsides with the ProNautic. First, the ProNautic 1220P charger isn’t water resistant. For best uses, you need to install them in a dry location, such as a cabin area where water can’t hit the unit. Ensure that you take this into account when you plan an installation.

Second, the supplied temperature sensor may be a tad short for some boaters. Although some users have mentioned they have spliced it to make it work.

Finally while a great choice for sailboats, the variable 20 amp capacity might be too low for big vessels.

Verdict:

Buy the ProNautic 1220P if you value a lightweight and capable smart charger. One that is useful for sail boaters who travel the world and need dependable power. For added confidence the ProNautic 1220P has a five-year warranty.

Top Heavy-Duty 3-Bank Onboard Charger

top marks label in blue with yellow check mark
ProMariner ProSportHD 20 Plus
  • Battery Chemistry Types: Wet Cell, AGM, Gel
  • Voltage: 12/24/36 Volts DC
  • AC Input Voltage: 120 VAC (+/- 10%) 50/60Hz
  • Amps Per Bank: Variable
  • Total Amperage: 20 A
  • Charging Stages: 5
  • Dimensions (inch): (L)7.9x (W)12.9 x (H)2.9
  • Weight (lbs): 7.8
  • Water Proof Design Standard: IP67
  • Warranty (years): 2
What We Like
What We Do Not Like

ProMariner ProSportHD 20+ Review

Are you a buyer who loves the ProSport20 model but want a little extra recharge power? Look no further, new for 2020 is ProMariner ProSportHD 20Plus. This is a 3 bank charger which boasts a tri-surface heat sink design. With industrial grade jacketed DC/AC cables, molded strain reliefs and wire splitters. This heavy-duty design makes it perfect for the harshest environments.

Top Notch Features

This ProSportHD provides automatic 5-stage distributed on demand charging via an enhanced microprocessor. This software delivers precise charging for enhanced battery performance. Rest assured that this bolstered charger provides faster charging through optimal cooling. Plus it will deliver true rated amp output during charge mode.

Another feature includes the easy to read fuel gauge style charge completion monitor. Other LED indicators show charge mode, individual fault indicators and three charge profiles. Including Group 24–31 Flooded (Wet cell lead acid), AGM and GEL batteries. For boaters with HP AGM batteries you will have to buy the ProSportHD 20 2-bank charger

A third feature that everyone will love is this charger is up to 40% lighter compared to an epoxy filled charger. Plus it has great built in safety with dual inline waterproof fuses. Other safety features include: reverse polarity, over-temperature, over-current, over-voltage and ignition protection.

Caveats:

One possible issue that may be a nuisance is the cable length. While they are 6 feet a user did complain about the need to splice an extension to a stater battery. Although the market average is three to six feet cables with every charger.

Verdict:

Pick the ProSportHD20Plus if you love the this brand but are looking for an even more robust charger. Or if you want a distributed on demand charger that is even lighter than its predecessors. As of today I love how reliable it has been to charge my batteries.

Perfect "Easy-To-Use" 3-Bank Marine Charger

Sale
Guest ChargePro 10/10/10
  • Battery Chemistry Types: Wet Cell & AGM
  • Voltage: 12/24/36 Volts DC
  • AC Input Voltage: 90–135V AC 50/60Hz
  • Amps Per Bank: 10 A
  • Total Amperage: 30 A
  • Charging Stages: 5
  • Dimensions (inch): (L)8.7 x (W)9 x (H)4.1
  • Weight (lbs): 8
  • Water Proof Design Standard: IP67
  • Warranty (years): 2
What We Like
What We Do Not Like

Guest ChargePro 10/10/10 Review

Redesigned from the inside out, the Guest ChargePro 10/10/10 onboard battery charger is capable and durable. This new design includes a low profile flange-less body made of extruded aluminum. Combined with sealed gaskets and heavy duty end caps it has a marine waterproof rating of IP67. Plus it’s shock resistant for all fresh and saltwater uses. The new exterior design delivers an increase in charging and thermal management performance.

Internal Features

Likewise, this onboard marine chargers comes with all the leading technology. Including digital automatic 5-stage performance charging. As well as all the built-in safety you need to set and forget while charging. Boaters will like the easy to read LED indicators for charge status.

Installing it is simple as everything has a easy to read label and the unit it pretty lightweight. Keep in mind though, marketing materials state you can install horizontal and vertical. Although the instructions states a vertical install only, which is confusing.

Once in use the charger is easy to use and takes care of the guess work. You can hook up and charge without any concerns, something we can all appreciate.

Downsides of the Guest ChargePro 10/10/10:

The first negative about this battery charger is that it’s only capable of charging Wet cell and AGM batteries. Which is fine if you have these two types of battery chemistry on your boat. But if you like to mix and match other types this charger won’t work for you. The second negative is that Guest provides a short warranty period compared to other brands. I would like to see them provide a bit longer period for peace of mind.

Verdict:

Buy the Guest 10/10/10 if you are looking for a perfect replacement of a Guest GU2631A or Marinco 28330 unit. Or if you want a simple to use and tough designed 30 amp onboard charger.

Cheapest 3-Bank Onboard Boat Charger

green budget friendly label
NOCO Genius Gen3
  • Made in the USA
  • Battery Chemistry Types: Wet Cell/AGM, Gel, Calcium, & Enhanced Flooded Battery
  • Voltage: 12 Volts DC
  • AC Input Voltage: 70-130 VAC, 50-60Hz
  • Battery Capacity: Up To 230 AH
  • Amps Per Bank: 10 A
  • Total Amperage: 30 A
  • Charging Stages: 8
  • Dimensions (inch): (L)11.1 x (W)8.4 x (H)3.1
  • Weight (lbs): 15.1
  • Water Proof Design Standard: IP68
  • Warranty (years): 5
What We Like
What We Do Not Like

NOCO Genius Gen 3 Review

For the budget minded buyer in 2020 the NOCO Gen3 3-bank marine battery charger is a good choice. Made in the USA, the Gen3 is a 10 amp per bank, 30 total amp smart charger. One which is also compact and a fairly lightweight unit.

This NOCO Gen3 has 100% sealed construction and rated at IP68, so it is a submersible onboard marine charger. As a result, you won’t have to worry about this model operating in the harshest environments. Likewise it is versatile, because it is compatible with many types of battery chemistry. Including Wet Cell, AGM, Gel, Calcium, and Enhanced Wet Cell (up to 230 amp hours).

With safety being a crucial buying factor, I like that NOCO provides so much protection in this unit. Including short circuit, reverse polarity, open circuit, spark, overheating, over-current, and overcharge protection.

NOCO also has a special mode known as “Abnormality protection.” This mode will turn off the charger if it is in bulk charge mode for an extended period of time. Although, I still find the same complaints that this mode doesn’t function as intended. In these instances users say their batteries have “boiled off.” This is an unfortunate factor to consider when looking at the NOCO Gen3

NOCO Smart 8 Stage Charging

Inside the Gen3 is an advanced VosFX microprocessor system for intuitive smart charging. This monitors the inputs to diagnose, recover, charge, and maintain batteries. It does this by running through an eight stage charging process. NOCOs’ intended result is to provide the best battery performance and longevity possible. A description of the eight stage process is below.

  • Stage 1 & 2 – Diagnose and Test

Checks the battery voltage to make sure battery connections are good and battery is in a stable condition.

  • Stage 3 – Soft Start

Begins battery charging process with a gentle charge.

  • Stage 4 – Bulk Charge

Starts Bulk battery charging process, returns 80% of battery capacity and voltage to 14.0 volt.

  • Stage 5 – Absorption Charge

Switches to a constant current charge rate to bring your batteries close to 90% charge.

  • Stage 6 – Taper Charge

Charges at low current levels until battery has reached 95% of its capacity

  • Stage 7 – Top-Off Charge

Charger initiates top-off charge to bring the battery to 100% charge.

  • Stage 8 – 24 Hour (Abnormality protection)

Shuts off, but will monitor the battery by providing a gentle charge every 24 hours for maximum battery life.

Downsides of the NOCO Gen3

I did find some downsides to the Genius Gen3, one such complaint happens when using it as a battery maintainer. The Gen3 only wakes up or tests a battery once every 24 hours. If you want the Gen3 to check and recharge batteries throughout the day, it won’t.

The next downside is my attempt to correct some confusion when it comes to the term “battery bank.” Most times a “battery bank” means more than one battery wired in series or parallel. But this isn’t NOCOs’ definition, they define it as one 12 volt battery equals one bank for this charger. Keep this in mind when choosing which charger is best for you.

Another concern I found is that the Gen3 isn’t capable of charging some AGM deep cycle batteries. These include, Odyssey and Northstar group 31 batteries. The reason for this is that NOCO uses pulse charging which can damage certain deep cycle AGMs.

One last possible annoyance for boaters in sunny locales is the LED lights. It uses green lights to state a full charge, but this color of green is almost impossible to see in direct sunlight. It is a pain in the butt to see the color to check status. Whereas the red LED charging lights are visible in the sunlight. For me, this is an added nuisance when using the NOCO Gen3 boat charger.

Verdict:

Buy the NOCO Gen3 charger if you want a budget friendly, 3-bank onboard charger. It’s capable of charging most batteries well, except certain deep cycle brands. The big bonus is its inexpensive and waterproof but realize this lower price does come with caveats.

Frequently Asked Questions: Onboard Marine Battery Chargers

Before the advent of a multi-stage marine battery charger, boaters experienced damaged batteries from over or under charging while using shore power. The reason for this was boaters had no choice but to use automotive type chargers. This type charger used voltage that was too high that results in off gassing that killed many batteries.

Today, buyers have quality marine chargers available to them. These chargers use special multi-stage charging, that monitor the voltage in the batteries. With some models being able to operate all the time if you do the installation correct.

To help you understand what to look for in a quality marine battery charger, I answer some popular questions that marine charger buyers ask.

What Is A 3-Bank Onboard Marine Charger?

A 3-bank onboard marine charger allows you to leave the batteries in the boat. First you mount and leave the charger installed in the boat all the time. Second, you don’t have to hook anything more to it to charge, just a plug in the AC cord attached to the charger. Inside an onboard charger are micro-computer controllers and the charge rate adjusts as the battery gets charged.

How Do I Size An Onboard Marine Charger?

Deciding what size charger to use is up to the user, dependent on some important factors.

  • First, sizing will depend on the battery size (Group size & Amp hour capacity) and type (Wet, Gel, AGM etc.).

The general consensus, is to size a hard wired onboard charger for at least of 10% of the banks rating in Amp Hours (Ah). The formula is as follows:

(Amp Hours) multiplied by (10%) = The amount of amps needed for correct recharge.

For example: A 300Ah battery bank, sized at 10%, would get a 30A charger.

  • Second, is what kind of recovery charge time is appropriate for your use.

All chargers have an amperage rating. This rating states how fast they can re-charge depleted batteries. The higher the rating, the quicker the recovery time. To help you choose a proper recovery time, check out the formulas below:

(amp hour rating of battery) divided by (charger rating in amps)= measurement

Next, (measurement) + 10% for top ups = required amps

A word of advice, using a higher rated charger for the intention of fast charging, isn’t a great idea. While chargers with lower amp hour output do have slower recharge. They are better for helping to reduce overcharging your batteries.

  • Third, is whether your boat has a continuous or intermittent source of AC power to run the charger.

Continuous Power (Shore)

If you spend a lot of time parked at the dock, you can pick a smaller charger. While you should consider voltage drops, many high quality chargers are “power factored.”

One factor you have to consider, is are there any DC loads your boat will use while at the dock. At dockside, DC devices can consume power and rob it from what your charger feeds the bank. Such as DC lighting, refrigeration, computers, TV’s, stereo. Ensure you have the capacity to power the DC loads and float-charge your batteries.

For example: Say you have a 10A dock-side load, with a 20A charger. This means that 10A is feeding your DC loads and the remaining 10A is going into the bank for charging. Your charger may be too small for your needs. In this example it’s in your best interest to pick a 30A charger to maintain a charge rate of 10% of Ah capacity.

Intermittent Power

In this instance you spend your time cruising or anchored out, and aren’t plugged in except every so often. Make sure to have stored “juice” to recharge DC loads and batteries in the time available. Take the total amp hour rating explained before and divide them by the hours available.

If you power your charger off a generator, get the largest charger as your batteries will accept. This is important to keep generator run times as short as possible.

Which Features Are Important For A Marine Charger?

  • Pick A Charger That Is UL 1236 Stamped

Quality boat chargers design should meet the ABYC / UL 1236 standards. These standards deem the proper safety and isolation of the AC and DC wiring in a battery charger. UL stamped chargers undergo a 1500 volt test! This test to makes sure there is adequate AC/DC isolation inside the charger. Electrical tests like this are paramount for safety out on the water.

  • Small Boats Need Sealed Chargers

If you have a small vessel (sport/fishing boat, kayak, etc) that’s gets wet, you need to buy a sealed charger. This allows for use in harsh environments and can operate if submerged for a short period of time.

Hot Tip For Larger Vessels:

It’s critical for chargers to remain dry, but at the same have adequate ventilation. If you install a charger in a cockpit locker or lazarette, try to mount it in a dry corner. Do not install it right under the hatch. Also give it a few inches of breathing room to help it stay cool while charging.

Another safety standard for small boats that a charger should meet is ISO 8846. Chargers with this rating, have ignition protection.

  • Choose A Multi-Stage Onboard Battery Charger

Any charger you consider at least offer a basic multi-stage charging profile. This includes a bulk, absorption and float charge. Another useful feature to have if you use Wet cell batteries is an equalization charge.

A bonus feature I like is having the ability to create a custom charging profile. This is great for unique battery bank setups.

  • Look For A Marine Charger With Varied Input Voltages

Good chargers work on varying input voltages and shouldn’t suffer from output limiting. Power factored chargers allow you to plug it in in many countries around the world. This feature is vital for cruiser style boats. Using a USA voltage specific charger will restrict your travel to US docks.

Another reason why this feature is important is due to the many docks out there with voltage drop issues. By picking a charger with 90-260 volts / 40-80hz input voltage you can hook up to most docks stress free.

Furthermore, wide input voltage ranges are vital for live aboard or cruisers. Due to their use of that use marine generators.

  • Built-In Safety Must Be Standard Equipment

The best marine charger is the safest. Get one with at least outside temperature sensing, with the sensor as standard equipment. Not as an ”extra”.

Hot Tip For Live Aboard Owners:

Skimping on safety can kill your batteries. In fact, many simplistic digital chargers can overcharge batteries. This usually happens during an extended absorption stage. This type of charger may stay in absorption stage until the charge current falls to a specific level.

For example: Your boat has a load that sips power and exceeds this specific level. The charger holds the batteries for extended times at high voltages which cooks them.

Other protections to look for are short circuit, over-charging, reverse polarity, and anti-spark.

  • Smart Absorption Charging For Wet Cell Batteries

If you have Wet cell batteries you need to pick a charger with a precise equalization charge stage. A Wet cell that gets left unused for a long period of time has a risk of electrolyte stratification.

Stratification is when the acid sinks to the bottom and the water rises to the top of the battery case. Allowing sulfates to crystallize on the lead plates. This leads to premature death of the battery.

A smart equalization charge will revert to short bursts of the absorption voltage. Which helps to get the electrolyte moving to mix with the water. Resulting in less sulfation and extended battery life.

How long does it take to charge a marine battery?

The simple answer to this is it depends on two ratings. First, the amp hours of capacity that a battery stores. Second, the amp rating of the charger you are using.This is a basic formula:

( battery’s capacity) divided by (amp rating of the charger) = basic charging time

Say for example: You have a deep cycle battery bank that has a capacity rating of 240 amp hours. In this instance, the current discharge rate of this battery is about 50 percent. As a result, this battery needs around 120 amp hours to charge it in full.

Next, to do this, you use a charger that can output 10 amps per hour ( 10 amp hour charger). This means that it will take 12 hours to refill the needed 120 amp hours of the battery in my example.

It total, this is a long time, and many active boaters don’t luxury of charging a battery for half a day . These boaters prefer a 20 amp hour charger, which cuts the example charging time by half, around 6 hours.

Can I use a car battery charger on a marine battery?

No! I recommend to never use automotive or non-marine chargers on boats. The intended use of a typical car charger is to revive a dead battery, it isn’t for maintaining it. What’s critical is, the design of a marine smart charger is for unattended use. Whereas if you use a car charger you need to track the voltage during charging.

Plus car chargers can increase stray battery corrosion. This is due to the fact many don’t isolate their AC & DC sides, like a UL stamped Marine charger will. Likewise, a car charger is prone to reverse polarity issues which creates shock hazards.

It’s in your best interest to stay away from car chargers for marine environments.

Can you overcharge a marine battery?

Yes! Overcharging your battery is common and can do more damage than under discharging your battery. If you overcharge your battery, you cause the acid inside to boil off. Resulting in your battery to crack or explode, ruining the battery and possibly your boat.

In Conclusion:

By now you should be able to make an informed choice for which 3-bank onboard marine battery charger is right for you. Using the right marine charger ensures enhanced battery performance and life expectancy.

Outdoors Informed loves to help you research so that you can spend more time out on the water.

Last update on 2020-11-25

Black o Green I which stands for Outdoors Informed with light grey back ground

This website uses cookies to ensure you get the best experience on our website: more info