Can I Use a Car Battery In My Boat?

Springtime usually brings a litany of questions about marine batteries or in some cases, car batteries in marine applications. One of the more commonly asked questions is whether or not a car battery can be used in a boat or marine application? The answer is a simple "yes," but does that mean a car battery is always the best choice for a marine application? Not necessarily.

The variety of marine applications is about as broad as automotive applications. Some boat engines don't need much power to start, while others are fire-breathing monsters that require the cranking power of multiple batteries to turn over. Other boats may use the same battery that starts the engine to power accessories, like live wells, showers, bilge pumps, stereos and other electrical accessories.

The best thing a boater can do before purchasing a battery, is understand how that battery will be used in their boat. If they just need a battery to start an engine, they should find one that equals or exceeds the engine's recommendations for cranking amps (or marine cranking amps). You don't really need to over-buy in this regard, but if your engine takes a while to turn over, you should take that into consideration when making a purchase.

If you need a battery that serves multiple functions, then you should definitely make sure the batteries you are considering are up to the task- they may work for starting an engine, but are they designed (and warrantied) for deep-cycle use? Is the battery you are purchasing a "house battery," intended not for engine starting, but for powering accessories? Also, another important consideration some folks miss is that car batteries typically come with terminals known as "SAE" terminals, which are lead posts roughly about the diameter of a nickel. However, many marine applications use connections that are designed for eyelets to be slipped over a threaded stud on a battery and secured to a lead base with a wingnut. Imagine the frustration of going to the store, purchasing a battery and bringing it home, only to realize the battery posts and terminal connections are not compatible?

Fortunately,  OPTIMA Batteries' BLUETOP Batteries address these issues and many more. All OPTIMA BLUETOP batteries come with both threaded terminals and SAE automotive-style terminals. Our 34M BLUETOP battery with a dark gray case is designed specifically for engine starting applications. All other OPTIMA BLUETOP batteries, including the D34M with the light gray case, as well as the D27M and D31M are designed for both starting and deep-cycle use. The 34, 27 and 31 battery group sizes are all different, so make sure you note the space you have available in your boat, before making a purchase.

OPTIMA Batteries also have a "sealed" design, which means if you are bouncing over rough chop or big boat wakes, you don't have to worry about acid spilling out of OPTIMA batteries and damaging your boat. Our patented Six-Pack AGM design is also up to 15 times more resistant to vibration, than a typical flooded lead-acid car battery, which is important not only on the water, but if your boat is being towed down the road and your trailer is not equipped with a suspension system that offers the same level of refinement as your tow vehicle.

Some will cite the longer warranties on car batteries as a reason to choose those batteries over marine batteries. However, the fine print in many of those warranties will often exclude specific applications, like using a car battery in a boat. So why do marine warranties tend to be shorter than automotive warranties? The simple answer is that boat owners as a group don't do a good job of maintaining their batteries.

Many boats only see occasional use and when they're not being used, few have battery chargers or maintainers connected to the battery. Tender loving care isn't needed to keep a battery's voltage properly maintained, but some common sense helps. If you can connect your boat battery to a charger when it isn't in use, do it. If you can't keep your boat battery charged while in storage, make sure your battery (or batteries) is fully charged and disconnected when you put your boat away.

Maintaining proper voltage in your boat battery will not only improve performance, but it will also extend battery lifespan. We're so confident this is the case, that if you buy an OPTIMA BLUETOP battery from us and buy an OPTIMA 1200 series battery charger from us at the same time, we'll extend your battery's free replacement warranty by a full year!