Best Deep Cycle Marine Batteries for Boats

Bass Boat

Being an avid fisherman, while at the same time starting a family in Florida, I know all too well the value of a quality marine battery. It is not only a matter of performance, but often times about safety as well. Losing power to your appliances while in the middle of a cruise or a fishing trip is bad enough, but being on a vessel that is completely dead in the water is about as hopeless a feeling as one could experience.

So, when I decided to upgrade my batteries I made sure to perform my due diligence. I figured that it would be a waste to not pass on this information to others in a similar situation, so here is what I have came up with; bare with me, it’s a wealth of information.

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Choosing the Best Deep Cycle Marine Battery

Having a variety of options is great, but at a point options can begin to feel overwhelming, and having too many options can be downright confusing. The best way to overcome such confusion is to arm yourself with enough knowledge to be able to discern for yourself the small differences between similar products; In this instance, Marine Batteries.

The beauty of a site dedicated solely to Marine Batteries, is that you can gather all the information you need for analyzing the various criteria and applications of each battery, and then apply that knowledge by comparing and contrasting specs on the collection of batteries we have gathered. To keep things from getting too complex, we have went ahead and narrowed our list down to the ten batteries that we liked best.

Top Ten Of Our Favorite Deep Cycle Marine Batteries

Let’s get into the good stuff. Now that you have a better understanding of these things, we can take a look at some of the best ones on the market, and see how well you are able to remember all of this Marine Battery jargon we have learned in the process (feel free to cheat and refer back to our earlier notes)

Optima Batteries 8016- 103 D31M BlueTop Starting Battery

Optima Batteries 8016 103 D34M BlueTop Starting Deep Cycle Marine Battery

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This Dual Purpose Marine Battery is one of Optima Batteries most popular models. This is an Absorbed Glass Mat Battery, which lends itself to being both flexible and durable. Optima Dual Purpose Battery line can be identified by its blue top and light grey bottom. Feel free to mount this battery at any orientation, and expect that it would hold up to the strongest of vibrations. Heavier that the average battery, but reasonable by AGM standards, this unit weighs in at just under 60 pounds.

Optima Batteries high standard of quality can be attributed, in large part, to their unique manufacturing process. Rather than use the industry standard, flat lead plates, Optima uses winding spiral plates to achieve a more efficient output. This, along with Optima’s proprietary Six-Pack design, make Optima’s Batteries among the most energy-dense, and powerful on the market.

The specs of this model are impressive. With 900 Cold Cranking Amps, you can count on this battery to get the job done in even the coldest of conditions. The reserve capacity of 155 minutes goes to show that it is possible to have both power and longevity in a 12 volt battery. In deep cycle mode, the 8016- 103 D31M BlueTop is good for an amp hour rating of 75. It is no wonder why this model made our list; when you combine these metrics with the experience of Optima, a company which has manufactured over 100 million spiral cells, you get a top of the line product. For those in search of an AGM, Dual Purpose Marine Battery, the 8016- 103 D31M by Optima is near the top of our list. With a fair price point, it warrants serious consideration.

Optima Batteries 8016 – 103 D34M BlueTop

Optima Batteries 8016 103 D34M BlueTop Starting Deep Cycle Marine Battery

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Optima Batteries are among the most trusted in the industry. So much so, that their mid-tier product is often better than the best another company has to offer. Such is the case here. The 8016- 103 D34M BlueTop boasts the same exceptional manufacturing quality of the 8016- 103 D31M, in a smaller size and at a lesser price point. Unlike some other models with an offset alignment of spiral cells, the 8016- 103 D34M has a symmetrical design which, along with its reduced size and weight, offers users a bit more flexibility in where the battery can be placed. The result is a battery using the Six-Pack design and Spiral Plate technology, with more versatility than it’s larger counterparts, as well as a lower price point.

The specifications of this model are solid, and excellent considering the price. With 750 Cold Cranking Amps, you can expect to be able to use this unit in all but the coldest of conditions. The reserve capacity of 120 minutes and the Amp Hour Rating of 55, make this battery a fine choice for those in search of one, reasonably priced battery to take care of all their powering needs. Optima doesn’t just make Marine Batteries, but it doesn’t stop them from being among the most respected in the business. For those looking for a smaller, scaled back version of the ever-so-popular 8016- 103 D31M, here it is.

Vmaxtanks Vmaxslr125 AGM Deep Cycle Battery

Vmaxtanks Vmaxslr125 AGM Deep Cycle Battery

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This model is the most popular offered by Vmaxtanks. Due to the fact Vmaxtanks specializes in Deep Cycle Batteries of all varieties, you can rest assured that you are getting a quality product. This Absorbed Glass Mat Battery is a beast, both in size and performance. Made using military grade custom plates, and weighing in at 75 pounds, the VMAXSLR125 is very dense. However, since it is an AGM battery, it is able to withstand extreme vibrations and is capable of being mounted at a variety of angles.

The number that will get your attention, when researching this 12 volt, group 31 battery, is that is boasts an impressive 125 Amp Hour Rating. For those in the market for a 12 volt Deep Cycle Battery to get the job done during extended periods away from a battery charging source, the VMAXSLR125 should garner some serious consideration. With an affordable retail price, we really like this unit from a overall value standpoint.

Interstate (AGM) Deep Cycle Battery – DCM0035

Sealed Lead Acid AGM Deep Cycle Battery DCM0035

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This Interstate battery is an amazing value for those looking for a small Deep Cycle Battery. Weighing in at just over 21 pounds, the DCM0035 is roughly half the size of comparable models. It is a sealed lead acid AGM battery, so although it does utilize lead/acid, it is self contained and capable of being mounted at any angle. The fundamental appeal of this unit is that is sells for a fraction of the cost of more technologically advanced models, while requiring significantly less space.

With an Amp Hour Rating of 35, you are getting sufficient for short periods away from a power source, and with a low retail price tag and volume being small, you can easily obtain several of these and still spend less than you might on a more technological advanced, powerful model. We encourage those with budget restrictions to strongly consider the DCM0035.

Optima Batteries 8006 – 006 34M BlueTop Marine Starting Battery

Optima Batteries 8006 006 34M BlueTop Marine Starting Battery

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Look who made the list for a third time. What can we say, the team over at Optima knows how to make a great battery. This time we are taking a look at one of their premiere Cranking Marine Batteries. Easily identified by the BlueTop along with a DARK grey (not light grey, lie the Dual Battery models), the 8006- 006-FFP is largely recognized as one of the best Absorbed Glass Mat, Deep Cycle Marine Batteries. Weighing in at 38.4 pounds, this unit is much lighter than its Dual Capable counterparts, while maintaining all of the durability that we have learned to love about AGM batteries.

You can count on the 8006- 006-FPP to get the job done in even the harshest of climates, due to its 800 Cold Cranking Amps. The reserve capacity of 100 is spectacular for a Cranking Battery, even if it is less significant than it would be in a Dual Purpose unit. Due in large part to its flexibility and size, the 8006- 006-FPP makes an ideal candidate for those who can afford to house two small batteries, rather than one of the Dual Purpose variety.

Universal Power Group UB121000 Sealed Lead Acid Battery

Universal Power Group Sealed Lead Acid Battery

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The UB121000 by Universal Power Group is a powerful Deep Cycle Battery. Its power is reflected in its bulk, as the UB121000 weighs in at 58.9 pounds; on the heavy side. Per dollar spent, you could argue that this Universal Power Group, Deep Cycle Battery is top of the line.

The UB121000, a group 27 battery, boasts an Amp Hour Rating of 100, and at a middle of the road retail cost. From a pure value standpoint, this unit is impressive, and it doesn’t slack in the area of performance, either. The UB121000 garners among the most overwhelmingly positive reviews of any battery that we researched, so you’re not just taking our word for it, everyone else loves it, to. If you are in the market for an Absorbed Glass Mat Battery at a reasonable price, and weight is not a concern, give the UB121000 a look.

Optima 8040- 218 D35 YellowTop Dual Purpose Battery

Optima Batteries 8040 218 D35 YellowTop Dual Purpose Battery

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What can we say, the team over at Optima Batteries know what they are doing. The 8040-218 D35 YellowTop Dual Purpose Battery at number 7, marks the fourth time an Optima Battery makes the list. An Absorbed Glass Mat Marine Battery, this bad mamma jamma utilizes the same spiral plates and Six-Pack Design that Optima is known for, but at a fraction of the weight of it’s BlueTop counterparts.

The payoff for packing all of this Optima Battery goodness into just 36.4 pounds, is a small amount of power and flexibility. That said, the 8040-218 D35 YellowTop is is plenty of battery for most small vessels. This 12-Volt beauty boasts 620 Cold Cranking Amps. making is suitable for starting a motor in cold climates. The 98 minute Reserve Capacity is quite impressive, considering the weight of this AGM battery. It is no surprise this is one of Optima’s very top selling batteries.

Vmaxtanks MR107 85AH Marine Battery

Vmaxtanks MR107 85AH Marine AGM SLA Battery

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Vmaxtanks might just be one of the better kept secrets in the Marine Battery Industry. By specializing in Deep Cycle Batteries, they are able to produce an exceptional products at a very competitive price. An Absorbed Glass Mat Battery, it might be fair to call the MR107-85 a slightly scaled back version of the battery at number 3 on this list. Its 55 pound weight is well utilized, though, as this beast is made with military grade custom plates.

The MR107-85 boasts an Amp Hour rating of 85, as well as a Reserve Capacity of an impressive 160 minutes. This unit is undeniably a good value. We really like what the team over are Vmaxtanks are doing.

Odyssey 31- PC2150S Cranking Battery

Odyssey 31 PC2150S Marine Starting Battery

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We wanted to include at least one commercial grade battery on this list, and the Odyssey 31- PC2150S is what we settled on. For those willing to think outside of the box, it was an obvious choice. Even though this unit was not specifically designed as a Marine Battery, because of the combination of rugged construction and exceptional performance that it provides, we consider it a solid option. Odyssey prides itself on making Absorbed Glass Mat Batteries that are powerful enough to start any boat. You aren’t sacrificing longevity at the cost of said power, though, as the overall lifespan of the 31- PC2150S is typically quite impressive, as it can be expected to perform for up to 400 cycles (at 80% discharge rate).

This 77.8 pound hog boasts an incredibly 1150 Cold Cranking Amps, making it suitable for even the most harsh climates. Another area this beast excels is in turnaround time, as it can be brought to a full charge in about five or six hours This kind of power and efficiency comes at a cost, though, as the Odyssey 31- PC2150S retails for a high price point.

Mighty Max ML75-12

 Mighty Max ML75-12

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To round out the list we include one of the best Deep Cycle Battery values on the market. If you are looking for a reputable Absorbed Glass Mat Battery at a fair price, the ML75-12 by Mighty Max is about as good as it gets. The ML75-12 is smaller than its counterpart, the Wayne, but still weighing in at just over 50 pounds.

What is maybe most appealing about the ML75-12 is its retail price. It is one of the most reasonable prices on the list. The reduced cost is not without reason, though, as the Amp Hour rating of 75 is also less than that of most batteries on the list. If you want a quality AGM Battery, but don’t need something with a significant AH rating, than this might be the unit for you.

Gaining a Deeper Understanding of Deep Cycle Batteries

If you want to learn more about marine batteries, follow me as we have a closer look at the three primary genre of Marine Batteries: Cranking/Starting Marine Battery, Power/Deep Cycle Marine Battery, and the Dual Purpose Marine Battery.

A Closer Look at Marine Battery Genres

These batteries are the equivalent of a sprinter; a high power discharge for a brief period of time. Rather than providing a consistent, steady stream of power, these batteries but out a burst, in order to get your engine started, before turning over the powering duties to an alternator. These batteries can not be used to provide a steady source of power to appliances, as they will be vulnerable to overheating and causing damage to the battery and appliances alike.
Deep Cycle
If the Cranking Marine Batteries are the sprinters of the battery world, the Deep Cycle Marine Batteries are the marathon runners. These batteries discharge a low volume of power over extended periods of time. Ideal for providing power to appliances and electronics, without running the risk of overheating. This is the type of battery that most of us are familiar with.
Dual Purpose
The name speaks for itself. A Dual Purpose Marine Battery is a hybrid of sorts. It is capable of providing that boost of power needed to crank start most engines, while at the same time offering deep cycle capabilities, providing the possibility to deep cycle and provide a steady stream of power to appliances. The detriment of this flexibility is that is does neither of the aforementioned tasks exceptionally well. There is the chance that it is unable to crank some larger engines, like a true cranking engine can be counted on to do, as well as the possibility it doesn’t withstand the same long lifespan of deep cycling, like a true deep cycle battery can be counted on to do. For these reasons, some boating enthusiasts prefer using a two battery set-up. However, since space on small vessels can sometimes be at a premium, dual purpose batteries are often a necessity.

To summarize on the three different genre of battery; Cranking Marine Batteries are for starting your boat’s engine, Deep Cycle Marine Batteries are intended for providing a steady stream of power to appliances and such, and Dual Purpose Marine Batteries can do a little bit of both, essentially the jack of all trades, master of none.

Next I would like to touch on the various composition types of Marine Batteries. There are four different varieties, with each of them having their own benefits.

Battery Composition Types You Should Know

Flooded Battery
A traditional lead and acid battery, composed of wet-cells which contain a mix of distilled water and sulfuric acid. These batteries are popular because their lifespan, with proper maintenance, can extend beyond 1,000 deep cycles, and the up-front cost is the least prohibitive of all composition types. However, being a great value with a long lifespan comes at a cost, flooded batteries require constant upkeep as the interior of the battery is accessible to the elements. Also, this particular type of battery does not handle vibrations well, restricting where it can be used, since leakage of corrosive battery acid is quite hazardous. While there has been a trend recently of sealed versions of Lead Acid Batteries being offered, the sealing will be reflected in the cost, and the battery still contains the corrosive liquid. Flooded batteries also require proper ventilation, as they emit hydrogen gas. It also should be noted that although the upfront cost of a Flooded Battery is going to be the most cost efficient option at the outset, you will need to provide distilled water each time you refill, increasing the overall investment needed for operation.
Gelled Battery
A gelled battery is similar in a lot of ways to the Flooded Marine Battery, but with far fewer restrictions, due in large part to not being filled with liquid. If composed properly, a gel battery will be exceptionally resistant to vibration; generally speaking, very durable. Gelled Marine Batteries have a self discharge rate of roughly 1% per month, so they can be stored for long periods without being charged, and they maintain their properties for an extended timeframe. In addition to everything else, they are also sealed and maintenance free, so you have much less variance in the lifespan of a given battery. There are very few downsides to a Gelled Marine Battery. One of them is that you are left with no choice but to trust your battery has been properly gelled, as you can not investigate the inside of the battery, and there is a possibility with lower-quality Gelled batteries that the liquid does not gel properly. This will leave you vulnerable to the issues that Flooded Marine Batteries face, while paying the considerably more expensive price that is common among Gelled Marine Batteries. In addition to the unit itself costing more, many Gelled Marine Batteries require a special charger, as they need to charged at a voltage that is much lower than the average Marine Battery.
Absorbed Glass Mat (AGM)
Let me lead by saying that Absorbed Glass Mat Batteries are the future of Marine Batteries. For this reason, we chose to focus on AGM Batteries when selecting batteries for our list. AGM Batteries are totally unique in that they boast a completely different technological backbone than that of the other composition types. Sometimes referred to as Sealed Lead Acid (SLA) Batteries, they use electrolyte absorbed mats that allow oxygen and hydrogen to combine in a manner which generates its own water. The result is a battery that is nearly maintenance free, and durable enough to be placed anywhere, regardless of vibrations or mounting angle. However, because they are much heavier than their counterparts, AGM Marine Batteries might not be the best option when weight restrictions are a consideration. Speaking to performance alone, Absorbed Glass Mat Marine Batteries are widely considered the best option. On average, their lifespan is not quite as long as Gelled Marine Batteries, as they self-discharge at a rate of about 3% per month, and more importantly, they are vulnerable to being rendered completely defective if accidentally overcharged. Despite the risk of having to replace your unit sooner than expected, many of the most popular batteries on the market are of the Absorbed Glass Mat variety.
Lithium Marine Battery
Lithium marine batteries are the most recent composition type to hit the Marine Battery Market, after being used in other industries for a number of years. The technological make up of Lithium Batteries vastly differs from the Absorbed Glass Mat or Lead Acid varieties. In these batteries, it is lithium metal that is used as the anode. These batteries are lesser in weight than the average Absorbed Glass Mat Marine Batteries or the Wet-Cell Batteries. Lithium batteries are safer, more reliable and with fewer risks of damage. This is because Lithium Batteries are manufactured with protections against low voltage, reverse polarity, and short circuit in place. In other words, you can not overcharge a Lithium Battery, and they require absolutely no maintenance. At this point you are likely wondering why we aren’t all using Lithium Marine Batteries. Well, it’s because they are exponentially more expensive than any of the other battery composition types we have discussed. To the point that, at their current market rate, they are simply not a good value, unless you are operating without any kind of budget.


Now that we have a better understanding of the various composition types of Marine Batteries, I’d like to go over some of the metrics used to quantify their performance capabilities.

Marine Cranking Amps

The Marine Cranking Amps, or MCA, is the amount of amperage generated while starting the engine, in 32 degree fahrenheit conditions. For Cranking Batteries, this is the key metric. You want to check the recommended MCA of the engine in which you will be using the battery to start, and then buy a battery with an MCA which is GREATER than that recommendation. The logic behind this is clear, it is better to have a little more amperage than you need, than to be stuck not enough. At the same time, you don’t need to purchase a battery strong enough for a freighter if you are are only starting a small engine.

Reserve Capacity

The RC, or Reserve Capacity, is most imperative metric when shopping for a Deep Cycle Marine Battery. It is defined as the number of minutes the battery can discharge 10.5 volts by 25 amps. Essentially, it the higher the RC, the longer the battery will be able to charge your electronics and appliances. Look for your average quality Deep Cycle Marine Battery to have an RC in the range of 60-120 minutes. Anything less than this is reason to consider other options. Conversely, the best Deep Cycle Marine Batteries will have a rating of 180+. There will be a RC listed for Cranking Marine Batteries, too, but it is nearly insignificant, due to the nature of their use.

Cold Cranking Amp Rating

When considering your Cranking Battery options, you need to think about the climate in which you will be using it. If you are in a tropical climate, or somewhere that it rarely drops below freezing, Cold Cranking Amp Rating, or CCA, is not very important. However, if you do plan on using your battery in colder temperatures, you should look for a CCA rating of at least 500. The CCA rating is defined as the amount of amperage the battery will provide to maintain at least 7.2 volts for 30 seconds at 0 degrees fahrenheit. The aforementioned recommendation of a 500 CCA would be good enough to maintain 10 volts over the 30 second period. The colder the environment in which you intend to use the battery, the greater importance you should give to this metric.

Amp Hour Rating

AH, otherwise known as Amp Hour Rating, is the most important metric to consider when purchasing a Deep Cycle Marine Battery. The rating is defined as 20 hours worth of amperage output. In other words 20 x (amps per hour). So, if a battery has an Amp Hour Rating of 150, that means it is generating 7.5 amps per hour. By looking into the amps required for the appliances you will be charging, and doing a little math, you are able to determine the minimum AH rating required to power everything. However, you should always overestimate the Amp Hour Rating requirement, as it’s never a guarantee that a battery will discharge its entire amperage, each cycle, over the course of its life. Once again, it is always better to have more than you need, than vice versa.

Physical Properties

Now that we have an understanding of all of the metrics used to quantify a battery’s performance, or, for those of us who hated story problems in math class, we have them directly above to reference, at least. Anyways, let’s touch on one last thing. Please remember that batteries come in a variety of sizes, weights, and voltages. All of which you likely want to take into consideration before purchasing your battery.


Most Marine Batteries can be found in 12, 18, or 24 volts. For the sake of simplicity, we will be focusing on reviewing the 12 volt variety If you are operating a small vessel it is you will be able to get by on two quality 12 volt batteries. However, because of space and weight considerations, you may opt for a single battery with a bit more power. Larger boats with plenty of space, might be better suited for 18 or 24 volt batteries, but can typically be operated with a bank of 12 volt units. For those looking to operate a larger vessel on a single battery, 18 volt will sometimes be powerful enough, but got the cost difference it might be worth the added peace-of-mind you get with a 24 volt. Regardless, you should at very least be aware of what voltage your battery is.


You will typically find that all companies that deal in Marine Batteries offer similar menu of sizes. The sizes are most commonly listed as 24,27,31,34,6D,8D,10D,12D, etc. Often times you will find one of these numbers within the model number of the battery. When space is at a premium, and you are replacing a battery, find the exact dimensions of the old battery, either on the unit itself, or by researching the model number. When purchasing a battery for a new project, and space is at a premium, make sure to measure carefully, then use those dimensions to qualify a given battery. Don’t be afraid to be stringent on the size you desire, as most battery styles are available in a wide range of dimensions.


While the weight is largely just a byproduct of how large your battery is, it is still something to consider. If you are trying to minimize weight for speed or efficiency, you will want a single battery, and not one of the Absorbed Glass Mat variety. When replacing an old battery, finding one that is an exact match in weight is less important than matching size or voltage.

Our thoughts on deep cycle marine battery

You deserve an award for making it this far, I know that it was a lot. It will be well worth your time, though. From personal experience, I can say that the time I have put into gaining a better understanding of the Marine Battery industry has already paid dividends. I’ve been fortunate to have not had any battery shortcomings, but more importantly I haven’t worried about any battery issues either. It’s been worth it for the peace-of-mind alone. In addition to that, I have gotten help out countless friends with their battery selection. So, to wrap things up, let me just tell you what I am asked the all too familiar question of “what battery should I buy?”.

If cost is not an issue, and you want just a single battery to handle all of your Marine Battery needs, you can’t go wrong with the Optima Batteries 8016- 103 D31M BlueTop. There is a reason, we lead the list with it. Just in case you didn’t make it this far, we wanted to make sure you were in the know about our favorite. The truth is, you can’t go wrong with an Optima Battery. They are an industry leader with merit. So any of the Optima Batteries on this list would be a good bet. As a matter of fact, even though we love the BlueTop, the 8040- 218 D35 YellowTop is their most popular model.

Now, if it is a Cranking Marine Battery that you are shopping for, you don’t even need to exit the Optima Battery aisle at your local boat shop. The Optima Batteries 8006- 006 34M BlueTop Marine Starting Battery is a sure thing. The Cranking Battery version of the BlueTops is easily identified by its dark grey (rather than light grey) base. The Odyssey 31- PC2150S is no doubt the most powerful Battery on the list. That power is reflected in its price, though. If you are powering a large vessel, and operating without a budget, the PC2150S is a strong option, no doubt.

If you have decided that you would rather have a specialized Deep Cycle Battery to pair up with your Cranking Battery, you still can’t go wrong by sticking with Optima Batteries Cranking Battery, but we encourage you to consider either one of the Vmaxtanks models on our list, as well. We would not go as far as saying they make a better Deep Cycle Battery than Optima Batteries, but they are at very least in the same tier of quality. So, if due to size, price, or availability a Vmaxtanks Battery is more convenient for you, rest assured that you have purchased a quality Deep Cycle Marine Battery.

Now, if you are looking to save some money or if you’re operating on a budget, it is hard to go wrong with number 4 on our list, the DCM- 0035 by Interstate. When you can buy a solid battery at a price like this, it almost goes without saying that it should warrant some consideration. The fact it is also one of the smallest batteries on the market, just adds to its appeal.

As you probably noticed, there are no Lithium Marine Batteries on our list. As we talked about earlier, from a performance and efficiency point of view, these batteries are superior to all other alternatives. We are approaching this from a value standpoint, though, and Lithium Batteries would need to be several orders of magnitude better than the alternatives to justify the price increase, and they just aren’t there yet. It is quite possible that in the near future, the cost of said batteries comes down, as usually happens with emerging technology, but we aren’t there yet. You can trust I will be keeping my eye on the industry, though, and when the cost of Lithium Batteries becomes more practical, we will try to be the first to alert you.

Regardless of what route you take, armed with all of this knowledge, we are confident you will be happy with your decision. Thanks for stopping by, and make sure to check back soon, we have something else on the horizon. Happy boating!


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