Most outboard motors have to be used with a battery. Maybe you’re just starting out with a brand new outboard motor, or it’s time for you to buy a new battery for the first time.
How do you know what kind of battery to buy? What is the best type of battery for an outboard motor? Does it have to be marine grade or can you use other types of batteries as well?
Keep reading as we answer these questions and provide some recommendations for the best outboard motor batteries.
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Table of Contents
- How Do I Know What Battery My Outboard Motor Needs?
- The 3 Best Batteries for Outboard Motors
How Do I Know What Battery My Outboard Motor Needs?
If you have a new outboard motor, check your owner’s manual for specific suggestions about the type of battery you should use; different motors may come with different recommendations.
If your outboard motor already has a battery and you’re simply looking to replace it, examine the existing battery. You may want to choose a new battery that is the same type as the old battery you’re replacing.
If you’re still not sure what battery to use, there are a few things to keep in mind.
Firstly, most outboard motors only need a battery to start the engine. Once the motor is running, the alternator will then continuously recharge the battery as long as the motor’s in use.
These types of batteries, called starting batteries, provide a powerful burst of electricity to get the motor to turn over. They are not good for providing sustained power unless the alternator is continuously charging the battery.
In other words, you wouldn’t want to use a starting battery to power your boat’s electronics while the outboard motor is turned off. Doing so could drain the battery and leave you stranded on the water.
That said, you may be able to use this type of battery to power your accessories and other features while the engine is running since the alternator will be continuously charging the battery.
For powering your accessories, trolling motors, and other electrical components, it’s best to use a deep cycle battery. These batteries provide a lower stream of power sustained over longer periods of time, and they can be fully discharged without damaging the battery.
Some batteries are dual-purpose – they can be used as both starting and deep cycle batteries – but you usually need two different batteries to perform these two different functions.
Again though, in most cases, you will need a starting battery for your outboard motor.
It’s best to use a battery specifically rated for marine use. Marine batteries are designed to handle plenty of shocks and vibrations, can be mounted in various positions, and generally last longer when being used on a boat.
You can use other types of batteries as well, but they may not last as long.
The 3 Best Batteries for Outboard Motors
The best batteries for outboard motors combine numerous features; when shopping around, you want a battery that’s well-made, dependable, and you may want one that’s versatile as well so you can use it for multiple purposes.
The batteries we’ll look at in this review are some of the best options on the market. Though you can use other kinds of batteries, the three options below are specifically designed for marine use.
So, if you do a lot of boating and you’re serious about having the best battery for your outboard motor, check out these options.
1. Optima BlueTop Marine Starting Battery
- 12-Volt, 800 Cold Cranking Amps, Size: 10" x 6 7/8" x 7 13/16" tall, Weight: 38.4 pounds, Dual SAE & 5/16" Stainless Steel Stud Posts
This Optima BlueTop battery is specifically designed as a starting battery for use on your boat. It comes from a reputable brand and is one of the highest-quality marine batteries you can find.
This is a 12-volt battery, making it perfect for the majority of outboard motors. If you need 24 volts instead, simply wire two of these batteries together in series.
What’s more, this battery provides 800 cold cranking amps, which is more than enough to start most outboard motors easily. It has an impressive reserve capacity of 100 minutes, providing power for a short period of time even when the motor isn’t running.
The battery is roughly 10 by 7 by 8 inches and weighs a little over 38 pounds. Because of its unique spiral cell design, it can be mounted in nearly any position and is 15 times more durable against shocks and vibrations than other batteries.
What’s more, this battery allows up to 3 times as many recharges as similar batteries, giving you much better battery life–and longer battery life translates to more time out on the water.
This battery is an excellent choice for a variety of different outboard motors.
Users of this battery praise its long life, its ability to hold a charge longer than the competition, and its dependability throughout the year in a variety of different weather conditions.
That said, some users claim these batteries start losing their ability to hold a charge after only a year or two. To get the most out of your battery, make sure you take care of it, disconnect the battery cables when not using it, and store it in a cool, dry place.
What we like
- This battery is exceptionally durable.
- It can be mounted in any position.
- It provides 800 cold cranking amps.
What we don’t like
- This battery may start losing its ability to hold a charge over time.
2. Odyssey Trolling Thunder Marine Dual Purpose Battery
The Odyssey Trolling Thunder battery is a jack of all trades; it can be used for both starting and deep cycle purposes. It’s a large, powerful battery that will work well with many different types of outboard motors, including many of the larger ones.
- Cold Crank Amp (CCA)- 880; Better : Limited 3 and 4 year full replacement - not pro rata; Longer service life: 3-10 years of service life; save consumers time, money and aggravation; Longer cycle life
- Longer shelf life: Can be stored on open circuit without the need for recharging up to 2 years or 12. 00V, whichever occurs first; Recharge: Highest recharge efficiency of any sealed lead battery on...
Like the Optima reviewed above, this is a 12-volt battery and can be wired together in series if necessary. This battery can put out 880 cold cranking amps and has a reserve capacity of 135 minutes, so it is a bit more powerful than the optima battery.
Of course, it is also somewhat larger; the dimensions are roughly 13 by 11 by 10 inches, and the battery weighs nearly 50 pounds.
With this in mind, this battery is better suited for larger boats that will be able to accommodate this extra size and weight.
One of the most unique features of this battery is its tolerance of extreme temperatures. It will get your engine running no matter the air temperature and has an operational range between -40 and 176 degrees F.
As with the Optima battery, a few customers complained that this battery wouldn’t hold a charge after a couple years of heavy use. Again, be sure not to overuse or abuse the battery, and take care to store it properly in between uses.
What we like
- This is a heavy-duty battery that works great for large motors.
- It can operate in a wide range of temperatures.
- It provides 880 cold cranking amps.
What we don’t like
- It may not take as much abuse as some marine batteries.
3. Banshee Starter Battery for Outboard Motors
- Extreme Light Weight - Weighs only 4.95 lbs compared to most 20HL-BS batteries which can weigh up to 14 lbs
- Flush Terminal Design - Flush terminals for better compatibility
This Banshee starter battery is specifically designed to work with outboard motors that are 25 HP or less. It is a small, lightweight battery that is perfect for use with smaller boats and outboard motors.
This is a 12-volt lithium-ion-phosphate battery designed for starting small outboard motors. It weighs just under 5 pounds and has approximate dimensions of 7 by 3 by 6 inches, so it is much lighter and smaller than the other batteries reviewed in this article.
Of course, with its smaller size, it isn’t going to be as powerful. It provides 500 cold cranking amps and just 18 amp hours.
That said, it provides exceptional cranking power for a battery of its size and will work well with many different types of small outboard motors. Due to its lithium-ion construction, it lasts longer between charges than most starting batteries.
If stored properly, it will not discharge during storage and will last a long time even when it is not used regularly.
One unique feature of this battery is its emergency start button. If your battery dies while you’re out on the water, you can press this button and the battery will provide just enough power to start your motor and get you running again.
Though this is an excellent battery for small motors, it should not be used with larger motors, as it may not be able to handle the increased load. Make sure you are aware of your motor’s amp draw and amp hour needs before using this battery.
What we like
- This battery is small and lightweight.
- It is fairly powerful for such a small battery.
- It provides 500 cold cranking amps.
What we don’t like
- It is too small for many outboard motors.
As you may have noticed from the batteries we reviewed, high-quality marine batteries are not cheap. With this in mind, you may be tempted to use other types of batteries with your outboard motor instead. Is this okay?
Can you use a car battery for your outboard motor? How about a lawnmower battery?
Keep reading as we explore these frequently asked questions about other types of batteries and whether they are safe to use with outboard motors.
1. Can You Use A Car Battery For An Outboard Motor?
Technically, the answer to this question is yes.
Before you stick a car battery in your boat, though, make sure it meets the recommended number of cranking amps to start your motor, as well as the proper voltage. These recommendations can be found in your owner’s manual.
You should also make sure your motor is designed with an alternator so that it will charge the battery, as all car batteries are for starting purposes only and should not be used for deep-cycle functions.
In other words, if you use a car battery with your outboard motor, only use it to start the engine, not for powering trolling motors or other accessories.
Using a car battery is not always the best idea because marine batteries are made to handle a lot more abuse.
What’s more, car batteries are usually designed a little differently than marine batteries; the terminals on car batteries may not be compatible with the connections on your boat’s battery cables.
Some people spring for a car battery instead of a marine battery because the warranty lasts for a longer period of time. The problem is, using a car battery on a boat may void some warranties.
Before buying a car battery, be sure you understand the warranty and read the fine print. If you’re buying it for the warranty but the warranty doesn’t include marine use, you might as well just play it safe and buy a marine battery.
2. Can You Use A Lawnmower Battery For An Outboard Motor?
Again, the answer is technically yes.
A lawnmower battery will power an outboard motor as long as it has the proper voltage and amperage, as discussed above.
Generally, lawnmower batteries have a lower cold cranking amp rating than marine or car batteries, so a lawnmower battery may have some trouble starting your outboard motor in cold weather.
Again, lawnmower batteries should only be used for starting purposes, though they can power other devices as long as the engine is running and your motor’s alternator is continuously charging the battery.
Lawnmower batteries may not last as long as a marine battery would because they are not built for marine usage; they may not handle shocks and vibrations, temperature extremes, and humidity exposure as well as a marine battery would.
As with car batteries, the battery terminals may or may not be compatible with your cable connections; make sure you know what kind of connections you have before buying a battery.
The best type of battery to use with most outboard motors is a marine-grade starting battery. All of the batteries reviewed in this article are built with quality and marine usage in mind.
If you don’t want to spend the money for a marine battery, you can use a basic car or lawnmower battery instead; just make sure it has enough amps and is the correct voltage for your motor.
Happy boating and stay safe out there!