Marine batteries are a significant investment, and whether we’re talking about a starting battery to crank up your outboard, a dual-use battery that can start your engine and run your electronics, or a dedicated trolling motor battery, you need to know that you can rely on them, 100% of the time.
Proper maintenance is critical, of course, as is appropriate charging.
But in small boats that don’t include a built-in battery compartment, it’s easy to forget that your expensive battery is going to take a beating – and it’ll be much worse for wear!
That’s why a high-quality marine battery box is essential equipment.
But if you’re not sure what to look for – or even why a battery box is necessary – we’ve got you covered. Below, we’ll discuss the ins and outs of battery boxes, provide a complete buying guide, and review some of our favorites
Quick glance at the best marine battery boxes:
Table of Contents (clickable)
Related:
Best Marine Battery Boxes Reviewed
Minn Kota 1820175 Trolling Motor Battery Power Center – Best Marine Battery Box
Inside dimensions: (with lid off) L 13 5/16” x W 7 ¼” x H 8 ⅞”
Outside dimensions: (with lid and handle) L 14.9” x W 8.7” x H 15”
Group size: 24 and 27
Charging ports: 12v and USB
Battery meter: Yes
Minn Kota’s excellent trolling motor battery box is everything the Newport Vessels wants to be, though even it is subject to a small problem with an easy fix.
Let’s start with what we like.
The plastic case is solid and durable, and both the carrying handles to either side and strap are up to the task of hoisting a heavy battery. The lid is secure and more than does the job of keeping your battery dry.
I’m not sure I’d lift the box and battery by the top handle, but you can give it a try and let me know how it goes!
Two forward-facing terminals allow easy connection to whatever needs power, and they neither melt plastic on high settings nor come loose.
Minn Kota provides a 12v accessory port as well as a USB charging port. On the top left, you’ll find a useful battery meter that’s activated by a “test” button.
And both the accessories and the power supply are protected by a pair of breakers: one 10 AMP and one 60 AMP.
As you can tell, Minn Kota and Newport Vessels are offering very similar products, with the difference being that the engineers and quality control folks at Minn Kota did their jobs right – on all but one point.
On the inside of the box, the point where the exterior terminals connect to the wiring is shielded by a plastic cover. When you get your marine battery box, open that cover and tighten down all the hardware.
Users routinely complain that this connection comes loose from the factory, causing a variety of problems from power loss to engine damage.
With that note, we can recommend this battery box as a solid option.
Pros:
- Keeps your battery dry
- Solid, tough box
- Nice smart features
- Strap closure is strong
Cons:
- Often ships with loose interior terminal hardware
Attwood 9067-1 Heavy-Duty Acid-Resistant Power Guard
Inside dimensions: (with lid)) L 13 7/8″ x W 7 1/4″ x H 10 1/2″
Outside dimensions: (with lid) L 16 7/8″ x W 9 5/8″ x H 10 7/8″
Group size: 27
Charging ports: No
Battery meter: No
Attwood’s Heavy-Duty marine battery box is a good buy if you run traditional wet cell lead-acid batteries. Vented to ensure that dangerous fumes don’t build up during charging, it’s also made from plastic that’s resistant to battery acid – always a good thing with old-style power sources.
Sized to fit Group 27 batteries, be sure to measure yours and not rely on the generic sizing.
Some buyers are put off by the strap system that closes the lid on this battery box, but rest assured: it exceeds the Coast Guard requirements and can support 350 pounds.
In short, the lid isn’t going to come off, and it’ll be held down with sufficient force to allow you to carry this box – battery inside – by the handles on either end of the lid.
This basic box has one weakness: because it has been designed around old-style lead-acid batteries, it provides ventilation. That’s necessary, of course, but the holes that allow acid fumes to exit can allow water to enter.
Placed in the top of the lid, they’re a design feature that’s also a potential problem.
In rough weather or rain, you can cover them with tape, but be aware that you’ve now effectively sealed this box – a dangerous proposition during re-charging!
As Concordia University’s Environmental Health and Safety experts explain, “Vented lead acid batteries vent little or no gas during discharge. However, when they are being charged,
they can produce explosive mixtures of hydrogen (H2) and oxygen (O2) gases, which often contain a mist of sulphuric acid. Hydrogen gas is colorless, odorless, lighter than air and highly flammable. Oxygen is an oxidizer that can promote the burning or explosion of flammable and combustible materials. The mixture of two parts hydrogen to one part oxygen produced is perfect for an explosion.”
You must vent this marine battery box while charging!
Attwood’s battery box is also not ready to connect your battery to whatever needs power. For that, you’ll need to drill the box yourself and add the necessary hardware.
If that sounds like a hassle, there are probably better options out there for you.
But if a little DIY project is right up your alley, this is a good buy for wet cell battery users who aren’t looking for any bells and whistles.
Pros
- Awesome price!
- Solid strap system
- This box really is sized for Group 27 batteries
- Keeps your battery dry – if you cover the vent holes
Cons
- Only keeps your battery dry if you cover the vent holes
- Potentially dangerous if not vented during recharging
- No bells and whistles – just a basic plastic box
Newport Vessels Trolling Motor Smart Battery Box Power Center
Inside dimensions: (without lid) L 13 ¾” x W 7 ½” x H 8 ¾”
Outside dimensions: (with lid and handle) L 17” x W 10 ½” x H 14”
Group size: 24 and 27
Charging ports: 12v and USB
Battery meter: Yes (incompatible with lithium batteries)
Newport Vessels knows trolling motors and small boats better than most – they manufacture both – and at first glance, it looks like they’ve put together a solid smart marine battery box.
But as we discovered, design flaws hobble this box and, as a result, diminish our enthusiasm for it.
Let’s start with the good.
The plastic exterior of this box is built tough and thoughtfully designed, as you’d expect at the price point. Sporting rubber feet, it’s going to stay put even when not bolted down, and the plastic is durable and thick.
You’ll find two front-facing terminals ready to connect to your motor, so there’s no DIY and hassle as with the Attwood.
Newport Vessels has equipped this box with a 12v accessory port and a USB charging port, one on each side of the lid. And on the top, you’ll find an LED battery meter that’s activated by pressing a “test” button.
That’s a really nice feature and one I’m willing to pay for to avoid nasty surprises.
You’ll also find a pair of circuit breakers – a 10 AMP and 60 AMP – to help prevent potential issues.
Now for the problems.
The strap closure is not terribly strong, and lifting the box by the handle can result in the lid separating from the body – and taking wiring with it. That’s simply a design flaw that’s unacceptable.
If you choose this box, I recommend that you switch immediately to a stronger tie-down.
Also, some users have had issues when drawing a lot of power from the battery. Essentially, the terminals heat up as current flows, leading to melting of the battery box where it touches this metal.
Less frequently, the terminals can be pulled through the wall of the battery box, as there’s no attached backing plate to ensure they stay in place.
So what’s the verdict?
To be fair, the terminal issues are pretty rare – though they do happen. And Newport Vessel’s customer service really is very good.
But these issues, and the problem with the strap, are design flaws that no engineer should have allowed.
If you’re willing to buy a new strap immediately or already own a spare ratcheting tie-down, this might be a good option for – provided you run your trolling motor at slower settings.
Pros:
- Keeps your battery dry
- Rubber non-slip feet work well
- Solid, tough box
- Nice smart features
Cons:
- Strap closure is too weak to lift the battery box
- Terminals can heat up under heavy draw, melting the box
- Terminals can be stripped from the box as there’s no backing plate to hold them in place
Cutting Edge Trolling Motor Power Center
Inside dimensions: (with lid on) L 14″ x W 7.1″ x H 9.6″
Outside dimensions: (with lid on) L 17.6″ x W 10” x H 10.7″
Group size: 24 to 31
Charging ports: 12v only
Battery meter: Yes
Cutting Edge’s power center is easily the most expensive product on our list, and it has some nice design features to recommend it.
But we’re not convinced that it offers twice the performance of the Minn Kota.
The plastic exterior is thick and rugged, offering reassuring quality. It may just be the best of the bunch in this sense. The two carrying handles to either side are plenty tough, too, and you shouldn’t have any trouble toting your battery with them in hand.
Cutting Edge’s design is a little dated, however, offering only a 12v accessory port – no USB charging port. That’s not great for most anglers.
It protects that 12v port with a 30 AMP breaker, adding a 60 AMP breaker for the terminals.
And unlike its competitors, it offers a constant voltage meter that’s easy to read. It can be switched off, too, to conserve power – a very nice touch.
But is it really worth twice the price of the Minn Kota for that?
Only you can be the judge.
Pros:
- Expensive!
- Keeps your battery dry
- Solid, tough box
- Nice smart features
Cons:
- No USB charging
Homeon Wheels Trolling Motor Smart Power Center
Inside dimensions: (with lid on) L 13.3 x W 8.3″ x H ?”
Outside dimensions: (with lid on) L 16.7″ x W 9.9″ x H 12″
Group size: 24 and 27
Charging ports: 12v and USB
Battery meter: Yes
Homeon Wheels offers a competitively priced battery box with some great features and one simple draw-back: the absence of a 60 AMP breaker.
Let’s start with the plastic exterior. In this case, it’s pretty much run-of-the-mill heavy-duty plastic. I’d rate it as no better or worse than the others.
As the manufacturer notes, the strap and carrying handle on the lid are not designed to hold the weight of a battery. Instead, you’ll need to use the molded handles to either side.
You’ll also find the usual external terminals, ready to go, no trouble, no problems, no hassles.
And in a break with the apparent convention, Homeon Wheels provides two USB charging ports and two 12v accessory ports, so if you’ve got a lot of equipment to run, this might be the best option for you.
You’ll also find a voltmeter that’s easy to read and always on.
On the downside, those charging ports are protected by a 16 AMP breaker, but there’s no higher amperage breaker to protect a motor or throttle. That’s a serious design flaw to my mind, and it’s perhaps evidence that the intended customer base is more RV enthusiasts than anglers.
Is that a deal-breaker?
Only you can decide that.
But if you need more than one 12v or USB charging port, Homeon Wheels is the only game in town.
Pros:
- Keeps your battery dry
- Solid, tough box
- Nice smart features, including double 12v and USB charging ports
Cons:
- No 60 AMP breaker
Why Is a Marine Battery Box Necessary?
You may take a look at a sealed AGM or lithium battery, see the plastic insulating shield, and decide that it’s got you covered.
Don’t make that mistake!
As battery experts warn, moisture of any kind and batteries simply don’t play well together.
On the top of the battery, where you find the terminals, water can be a disaster. From spray to rain, waves to drips, water can collect on the top of your battery, pooling between the terminals. This can create a “bridge” between them, very quickly discharging your battery.
Corrosion is also an issue for the terminals, and though saltwater is more of a problem than fresh, don’t kid yourself that both will dramatically shorten the life of your battery.
Though a common myth states that batteries can sit in a little bit of water, keeping the bottom of your sealed battery wet can lead to failure
When sufficient water pools around the sealed base, discharge is likely. As the engineers at Northeast Battery caution, in these circumstances, “Although the plastic housing is meant to be an insulator, a charge will slowly move out of the battery.”
What We Look for When Selecting a Marine Battery Box
Waterproofing
A marine battery box doesn’t need to be truly waterproof, but it does need to provide complete protection from spray, rain, drips, and waves. At the very least, expect a cover that overlaps the base and prevents water from getting inside.
Even then, it’s a very good idea to check your battery at the end of each trip to ensure that it’s completely dry.
Easy Access
Whether you’re charging or jumping another angler, you’ll want easy access to the terminals.
Look for marine battery boxes that already have external terminals attached, but watch out for the quality of those connections.
Several of the products we review have poor connections on the inside, where the terminals connect to the wires leading to the battery. In one case (Newport Vessels), they’re poorly insulated against heat, leading to potential melting issues, and poorly secured, allowing them to strip out.
Portability
Marine batteries are heavy – that’s a fact!
And many small-boat anglers can’t leave their expensive batteries in place at the end of the day. So it’s important to look for a marine battery box with generous, strong carrying handles to help you lift and tote that monster.
Typically, models that come with an attached handle on the lid should still be lifted by the side handles.
The strap and handle are usually not rated for the weight of a marine battery.
Sizing
Proper sizing is pretty important – if your battery won’t fit in the box, or if the box won’t fit in your boat, you’ve got a serious problem!
Don’t trust group sizing. Even if a battery box tells you that it will accommodate Group 24- and 27-size batteries, and you’re running a 24, measure.
Look carefully at the interior dimension of a potential box, and then measure your battery, including the terminals, to see if it will fit. Remember: if there’s too much space inside, you can always use pieces of solid styrofoam to hold your battery in place.
But whatever you do, don’t guess – and don’t estimate.
You also need to measure the space in your boat carefully and be sure that the box you like will fit where you want it.
Smarts
Modern battery boxes are a lot more than a plastic shroud, and from battery meters to USB ports, it’s probably worth investing in a “smart” box.
Why?
First off, there’s quite a bit of peace of mind to an easy-to-read battery meter. No more guessing about your remaining charge, no more hoping that you’ll have enough juice for your trolling motor at the end of the day, and no more surprises when something starts to go wrong.
Second, a 12v and USB charging port offer plenty of ways to keep your electronics and other powered-up, and once you’ve had this luxury, you’ll be hard-pressed to do without it again.
The good news is that this stuff is pretty much standard on every marine battery box but the most budget-level.
To my mind, this was a pretty easy choice.
You want a battery box that can take a beating and keep your power supply dry. You also need pre-placed external terminals, a decent battery meter, and 12v and USB charging ports.
And with all that power, a 20 to 30 AMP breaker for the ports and a 60 AMP breaker for the terminals is a wise inclusion.
That doesn’t sound like a tall order, but only the Minn Kota managed to fulfill those requirements.
And while you’ll want to tighten the internal connections immediately, once you do, you’ll find this marine battery box delivers.