Best Marine Battery – Dual Use, Starting, and Deep Cycle Batteries Explained and Reviewed

Have you ever been out on the water with your trolling motor fail? Worse, have you ever tried to start your outboard while driving miles away from the boat ramp?

This is a powerful feeling that you need to feel once to understand the importance of taking your batteries seriously.

It can be difficult to find marine batteries that are reliable and safe. We are here to help. Below, you will find a detailed explanation, a guide, and a list of batteries that you can trust. Although we have limited space, we can only focus on Group 31 and 27, but you can ask for other information in the comments.

Here’s a quick look at the top marine batteries currently available:

Cranking/Starting Batteries

  • Bass Pro Shops Pro Series AGM X-900 Marine Battery Group 27Our Choice!
  • Lithium Pros M3180 12V 80Ah Marine Starting Battery
  • NorthStar Ultra High-Performance Group 31 Battery

Dual-use Batteries

  • Odyssey 31M Trolling Marine Dual Purpose BatteryOur Choice!
  • Deka 8A27 AGM Deep and Starting Cycles
  • Deka 8A31 AGM Deep and Starting Cycles
  • Optima Batteries D31M blue top starting and deep cycle

Deep Cycle Batteries

  • VMAX MR127 Deep Cycle –Our Choice!
  • Interstate Batteries SRM-27
  • Interstate Batteries SRM-31
  • Lithium Pros M3140-36 36V 40Ah Trolling Battery

Best starting/cranking marine batteries

Bass Pro Shops Pro Series AGM X-900 Marine Battery Group 27 – Our Pick!

Type: AGM
RC:195 minutes
MCA:1080 Amps
CCA:930 Amps
Weight:68 lb.
SizeGroup 27; 6.77×12.44×8.74 (with terminals).

Bass Pro’s Group 27, X-900 is a great choice for smaller spaces. It has a lot of starting power and provides 195 minutes of RC. This is a remarkable feat that explains why the battery is so well-respected.

Many anglers use this to start their outboards and their trolling motors. This is acceptable because they can withstand deep discharge.

However, you should be careful with your outboard. Keep one battery for starting (if you have the room)

This battery, like its bigger brother, has been tested by anglers from all over the country. As long as you take care of your AGM battery, it will start your outboard regardless of the weather conditions. It’s easy to care for an AGM battery.

Pros

  • Dependable at all temperatures
  • Excellent CCA and MCA
  • Great RC

Cons

  • Heavy

Lithium Pros M3180 12V 80Ah Marine Starting Battery


Type: Lithium-Ion
RC:184 minutes
MCA:1200 Amps
CCA: What is the best way to get started?
Weight:25.2 lb
SizeGroup 31; 6.81x13x8.43

The Lithium Pros M3180 high-tech starter battery is comparable to AGM batteries for power output and weight. It weighs in at 25.2 pounds and delivers 1200 Amps MCA.

This is a great deal for budget-minded anglers who are concerned about weight. Make sure you properly recharge the lithium-ion battery.

This battery is amazing–and very expensive!

Pros

  • Ultra light-weight
  • Amazing MCA
  • Great RC

Cons

  • It’s expensive!

NorthStar Ultra High-Performance Group 31 Battery

NorthStar Ultra High Performance Group 31 AGM Battery

Amazon

Type: AGM
RC:220 minutes
MCA:1370 Amps
CCA:1150 Amps
Weight:76 lbs.
SizeGroup 31; 6.8×12.9×9.2

The Northstar Group 31 AGM starter battery is popular for large-outboard anglers. It can be used in two roles, just like the Cabela’s X-900. You run the risk that you will discharge it too much and it won’t be able to start your motor. We recommend that you reserve one for this purpose.

We recommend the X-900 series of Cabelas X-900s as the heaviest starting battery.

Pros

  • Dependable at all temperatures
  • Amazing CCA and MCA
  • Great RC

Cons

  • Heavy!

Best Marine Batteries for Dual Use

Odyssey 31M Trolling Marine Dual Purpose BatteryOur Choice!

Odyssey 31M-PC2150ST-M Trolling Thunder Marine Dual Purpose Battery

Type: AGM
RC:205 minutes
MCA: What is the best way to get started?
CCA:1150 Amps
Weight:77.8 lbs.
SizeGroup 31; 6.80x13x9.41

The Odysseys Group 31 “Trolling Thunder”, a dual-use battery that delivers plenty of power and incredible RC for a great price, is an excellent choice. If you are careful when using the throttle, that’s enough juice for your trolling motor to run all day.

While not as light as “Blue Top”, Odyssey has been delivering exceptional quality control and enviable performances, stealing many former Optima fans.

This battery has enough cold cranking amps for an outboard to start on cold mornings. It is almost twice the price of an Optima.

Pros

  • Dependable at all temperatures
  • Amazing CCA and MCA
  • Amazing RC

Cons

  • Heavy

Deka 8A27 AGM Deep and Starting Cycles

Deka Battery 8A27 Battery

Type: AGM
RC:185 minutes
MCA:900 Amps
CCA:580 Amps
Weight:63 lb.
SizeGroup 27; 6.75×12.75×9.86

Deka’s Intimidator batteries are a reliable choice for anglers who know their stuff.

Although the Group 27 AGM battery by Deka can start most outboards it has a lower performance in cold temperatures with 590 cold-cranking amps. This battery is still a good choice for smaller outboards.

This battery has 185 minutes of RC and can power basic electronics while still holding enough charge to start your motor. All this with very little maintenance.

Pros

  • CCA and MCA are good
  • Great RC

Cons

  • It is not ideal for cold temperatures.

Deka 8A31 AGM Deep and Starting Cycles

Deka Intimidator Battery (AGM) 8A31DTM

Type: AGM
RC:210 minutes
MCA:1000 Amps
CCA:800 Amps
Weight:69 lbs.
SizeGroup 31; 6.75x13x9.5

The larger Intimidator from Deka offers impressive cold start amperage and full RC for 210 minutes. This is enough power to crank your trolling motor on cold mornings. It also provides 210 minutes of RC, so make sure you control the throttle.

This goes a long way in explaining why the Odyssey has such a good reputation. However, for the price, the Odyssey is the best.

Pros

  • Dependable at all temperatures
  • CCA and MCA are good
  • Great RC

Cons

  • Performance is a bit behind Odyssey Odyssey at the same price point

Optima Batteries D31M blue top starting and deep cycle

Optima Batteries 8052-161 D31M BlueTop Starting and Deep Cycle Battery

Type: AGM
RC:155 minutes
MCA:1125 Amps
CCA:900 Amps
Weight:59.8 lbs.
SizeGroup 31; 6.56×12.81×9.38

Optima’s Blue Top batteries have a large following on the water. However, quality control has slipped in recent years. These batteries are among the most high-quality you can purchase if they are well-made. They can fail quickly and require warranty claims.

Unfortunately, Amazon is not a licensed seller, so Optima will not honor your warranty if you buy through them. These batteries can also be purchased directly from the manufacturer through O’Reilly and NAPA.

They are so popular because of this.

This Group 31 battery weighs in at just 59.8 lbs with a CCA rating of 900 Amps, 155 minutes of RC, and a weight of only 59.8 lbs. Its unique spiral-core technology provides a lot of juice and keeps the weight down. The “Blue Top”, at its best, can be used to power your trolling motor or start your outboard. It has been proven to keep a charge for fishing all day while still delivering enough power to start large outboards even in the coldest weather.

Pros

  • Dependable at all temperatures
  • Amazing CCA and MCA
  • Great RC
  • Relatively lightweight

Cons

  • Low-quality control can cause short-term life expectancy

Best Deep Cycle Marine Batteries

VMAX MR127 Deep CycleOur Choice!

VMAX MR127 12 Volt 100Ah AGM Deep Cycle Maintenance Free Battery Compatible with Boats and 40-100lb, minnkota, Cobra, sevylor and Other trolling Motor (Group 27 Marine Deep Cycle AGM Battery)

Type: AGM
RC:200 minutes
MCA:800 Amps
CCA: What is the best way to get started?
Weight:68 lbs.
SizeGroup 27; 6.75×12.1×8.2 (8.46 when using terminals).

The VMAX MR127 is a very popular deep-cycle battery. This is also the most affordable.

This battery is one of the most powerful trolling motor batteries available. It can deliver 200 minutes of RC, and it can withstand deep discharges year after season. This battery requires very little maintenance and, if properly charged, can last for many years.

Pros

  • Reliable
  • Amazing RC
  • Tolerates deep discharges, season after season

Cons

  • Heavy

Interstate Batteries SRM-27

VMAX MR127 12 Volt 100Ah AGM Deep Cycle Maintenance Free Battery Compatible with Boats and 40-100lb, minnkota, Cobra, sevylor and Other trolling Motor (Group 27 Marine Deep Cycle AGM Battery)

Type: Wet-cell
RC:160 minutes
MCA: What is the best way to get started?
CCA:600 Amps
Weight:50.3 lb
SizeGroup 27; 6.75×12.75×9.5

Interstate Batteries’ SRM Series are trusted by both anglers as well as battery experts. They deliver the power you need for electronics, trolling motors, live wells, and live wells. They are old-fashioned wet-cell technology, and they work if you take care to maintain them properly.

The Group 27 battery weighs in at 50.3 pounds and provides 160 minutes of RC. That’s a pretty good performance-to-weight ratio, and they tolerate deep discharges for years.

Be aware that these batteries are acid-water sensitive and you should avoid spilling.

You can expect long-term service, outstanding performance, and a great price if you are willing to do it!

Pros

  • Reliable
  • Good RC
  • It’s affordable!

Cons

  • Performance lags behind VMAX

Interstate Batteries SRM-31


Type: Wet-cell
RC:210 minutes
MCA: What is the best way to get started?
CCA:675 Amps
Weight:59.7 lbs.
SizeGroup 31; 6.69x13x9.63

Interstate Batteries’ Group 31 deep-cycle model is incredibly powerful at a lightweight of just 59.7 pounds. You can even run a trolling engine all day with 210 minutes of RC!

The SRM-31 uses wet-cell technology, so it is a great option if you have specific needs.

Pros

  • Reliable
  • Great RC
  • It’s affordable!

Cons

  • Performance lags behind VMAX

Lithium Pros M3140-36 36V 40Ah Trolling Battery

Type: Lithium-Ion
RC:92 minutes
MCA: What is the best way to get started?
CCA:675 Amps
Weight:30.3 lbs.
SizeGroup 31; 6.81x13x8.43

The Lithium Pros 36V deep-cycle battery can replace an entire bank lead-acid battery and provide up to nine hours of power for your trolling motor. Even the heaviest boats won’t be affected by those 92 minutes worth of RC at 30.3 pounds.

The downside? Be prepared for the price!

Pros

  • Reliable
  • Good RC
  • Three 12v batteries can be replaced for only 30.3 Pounds This is it!

Cons

  • It’s insanely expensive!

Battery School: What you need to know when choosing the best marine battery

Basics of Battery Management

The idea behind batteries is simple: They are a way to store electricity so you can use it later. This simple idea requires some complex chemistry to make it work. You can make the right choice by having a good understanding of battery technology.

Three internal components of a battery are important to know: a negative, a positive, and an electrolytic medium. These are typically lead plates, acidic liquids, or gels in conventional batteries. These materials can be replaced with carbon or lithium salts in some advanced batteries.

Battery Tech: SLA/VRLA/AGM and Wet-Cell vs. Lithium-Ion

The technology behind battery tech has advanced significantly over the past 20-30 years. You may not even be aware of all the different types of batteries available. You can choose the best one for you by understanding your strengths and weaknesses.

Sealed Lead-Acid, Valve-Regulated Lead Acid (VRLA), Absorbed Glass Mats (AGM), and Sealed Lead Acid (SLA)SLA/VRLA batteries are basically three terms that refer to the same chemical system. They use lead plates and acid for their basic components. AGM batteries also have an additional chemical trick. This tech results in AGM batteries that are all safe and heavy, and don’t need to be maintained like traditional wet cells.

These batteries are more durable than wet cells, but they can be damaged by excessive charging.

Gel batteries el batteries are also made from lead plates and acid. However, silica is added to the electrolyte to make it thicker. They have a superior long-term storage capability and, like AGM batteries, are very safe and easy to maintain.

They don’t like strong, sudden discharges which could cause damage to the plates. They must be charged carefully and not exceed their maximum charge.

Lithium-Ion, also known as Li-ion.These batteries convert from lead and acid to lithium and carbon to provide power. They are rechargeable quickly and generally lighter than AGM or SLA batteries with the same power. They are simply better technology.

But what’s the downside? These systems can be extremely expensive and can even cost thousands of dollars for marine use.

Wet-Cell BatteriesSince their inception in the late 19th century, wet-cell batteries have remained relatively unchanged. They are very popular due to their low price and can withstand many charging cycles if they are well maintained. They are also resistant to overcharging, and they weigh a little less than other SLA or AGM options.

They require ventilation and can spill acid and leak, they don’t retain a charge well in storage and they can be damaged by vibrations that are common in marine use.

Different types of marine batteries

Three types of batteries are commonly found on boats:

Starter or cranking battery –To increase the chemical reaction’s surface area, lead/acid starter batteries make use of many lights, spongy plates. This greatly increases the power they can produce in a short period of time. It allows them to turn your engine and provide the power required to run pumps, fuel injections, and other essential engine components.

They can’t provide low power for long periods of time because the plates aren’t made for it. Two things are certain to happen if you attempt. You’ll drain your battery quickly and permanently damage it by deeply charging it.

Starter batteries are intended to start the outboard and not run a trolling engine. If you don’t run your outboard (and its alternator), you will quickly drain a starter battery.

Even then, it’s important to keep your phone charged onboard.

Deep cycle –To create the chemical reaction that stores and discharges power, lead/acid deep-cycle batteries are made of heavy, solid plates. They can provide low levels of electricity for long periods. The plates and acid are also designed to allow for deep discharging and repeat recharging.

They can be used to discharge up to 20% of their capacity without causing damage, unlike conventional batteries.

Deep cycle batteries do not have plates that generate high power quickly, so most people will have trouble starting an outboard. They may not be able to turn the engine over even if they manage to do so.

Deep cycle batteries can be used to power electronic devices such as fish finders, GPSs, and radios.

Dual-use batteries –Dual-use batteries are the best of both worlds. They have enough surface area to produce a burst in power and enough plate mass to sustain deep, uninterrupted discharges without any damage.

They combine the best of both deep cycle and dedicated cranking batteries, but are not as effective at starting motors.

You can safely discharge dual-use batteries up to 50% of their capacity.

Marine batteries –Marine batteries are sometimes used to refer to “deep cycle”, but they can also include any other types depending on their intended purpose.

How can you choose the right battery for your needs?

We’ll be focusing on small boat batteries, such as those used for crappie and bass fishing, inshore fishing for reds and speckled trout, flounder, and other types of fishing. It’s almost certain that you are running a trolling engine and electronics. You’re not just starting an outboard or inboard engine. You’re not trolling offshore for hours on your main engine.

Not all off-shore boats can use the same recommendations that we make.

You’ll see a simple truth when you stop and think about how your boat’s battery is being used. 99.9% of the time, you’ll use them to power your trolling motors, fish finders, live wells, lights, and other electronic devices. You should think carefully about the battery you choose, given the power requirements of modern electronics.

Even though only a small fraction of the battery’s time can be spent on starting your outboard, it’s still a crucial task!

The Limiting Factors are Space and Cost

You’ll need more room for batteries the larger your boat. It’s not practical to fill all the space with batteries, considering how much tackle we carry. You’ll also be broke by the cost of batteries!

You only have one battery space in your boat, and you are running a trolling engine as we assume, you don’t have many options. A dual-use battery will be required to start your outboard.

Always read your owner’s manual and make sure you choose a battery that has at least the recommended cold-cranking amps or marine cranking amps (MCA) of the manufacturer.

You may be able to store more than one battery. A dedicated cranking battery and a deep cycle battery are good options. You should run multiple identical batteries in parallel to power your trolling motor at 24v and 36v. The cranking battery will be used for the live well, electronics, as well as getting your outboard running.

You can also choose dual-use batteries that have enough cranking power for your outboard.

No matter which option you choose, make sure to use an onboard charger that is of high quality. This is especially important for your outboard battery!

How to Choose the Best Marine Battery

CCA or MCA

The Cold Cranking Amps (or Marine Cranking Amps) is an indicator of how much amperage a lithium battery can provide in a short time, at low temperatures. They allow you to turn over the motor and get it running smoothly.

Experts can tell you that “CCA” is a rating used by the battery industry to determine if a battery has the ability to start an engine in cold conditions. It is generally easier to start an engine when it is warmer than it is in colder environments. A rating is the number of amps that a 12-volt battery can deliver at 0degF (30 seconds) while maintaining a voltage of at least 7.2volts. CCA ratings are higher than those of starting power. MCA, which is the same rating applied at 32degF should be greater than CCA.

Your battery must meet the minimum requirements for your outboard. We recommend that you allow yourself some extra time to start in cold conditions or when your battery is not fully charged.

Reserve Capacity

Simon Playford from Hunker explains that “Reserve Capacity” is the time a fully charged 12-volt battery can supply 25 amperes at 10.5 Volts until the voltage drops.

You might have heard that RC is just a number. However, a battery’s RC does not accurately reflect how much run-time it gets. This depends on many factors including temperature and power draw.

Weight

Even light-weight batteries can be heavy. The heavier your boat is, the more important this is. Outboard performance can be affected if there is not enough battery bank in a fiberglass bass boat.

This is something you should consider when deciding on how big a battery bank to use. It can also help to justify the additional cost of lithium-ion cells.

Size

Take care! There are many sizes of batteries, and larger batteries are generally more powerful.

However, if the battery doesn’t fit in the place you need it to, it won’t do much good.

Price

There are many battery prices. It is worth considering the differences between long-term and upfront costs. A battery that lasts years might be more expensive in the long term.

Battery Tips

Never mix battery types

AGM, gel, and wet-cell batteries should never be mixed. Your batteries should be charged on the same system every time.

Never mix old and new batteries

The new battery will rapidly deteriorate if it is added to an existing bank. It’s time for all the batteries to be changed when it’s time.

Keep your Terminals Clean

Check the battery terminals regularly and get rid of any corrosion.

Keep your Batteries Cold

Temperature extremes can affect storage life and performance. No battery likes being hot or cold. This is something you probably know if your car was unable to be started when temperatures were below freezing. However, extreme heat can also cause problems.

Keep your battery dry and cool when you aren’t using it. Your battery must remain charged and not depleted, so make sure you top it up before you put it away.

Recharge slowly

If you don’t choose a pack that plugs into standard outlets, you will need to purchase a battery charger. Slow charging is better than fast charging, so it’s crucial to never overload your battery. Many batteries can be charged overnight.

Do not run them to death

Many deep-cycle batteries can be recharged hundreds of times. If you take good care of your expensive lithium batteries, they can last thousands of cycles before eventually becoming obsolete. Avoid draining your battery completely. It’s best to keep it at least 50% charged if you want the longest possible service life.

Last Thoughts

There is no one “best” battery. Only the best for you and your boat. We have the right battery for you, whether you need a starting battery to start your outboard in spring or a bank of deep-cycle batteries to power your trolling motor all day.

We hope that you will find what you are looking for on our list. However, we were limited in the space available to review Group 27 & 31 batteries.

Please leave a comment below if you have any questions or need to make a recommendation. We are happy to assist you!

Lewis
Lewis Mark is a vastly experienced fly fisher. His encyclopedic knowledge of fly tying has led to start blog on fishing. He also review Fishing equipment based on his knowledge and experience.