The initial source of power in marine crafts is the battery, thus it is immensely important to keep it up to par. The related fuses, wiring, and circuit breakers and other components that help maintain and keep the battery running properly are also important to maintain. If not enough attention is paid to that previously mentioned components, the quality of work expected out of the boat will be much less than previously expected.
Batteries, not too many years ago, were only available as 6-volt and 12-volt batteries; with very few choices as to ampere rating, sizes, and specific applications, batteries were an uncomplicated tool. Today there is a large, confusing list of options available on the market. How to choose between a Group 24, Group 27, cranking battery or a deep-cycle? What amp has the best rating, and what do the ampere ratings mean?
Each boat engine available must have a specific marine battery chargers to ensure proper performance, whether stern drive, outboard, or onboard. Battery performance is not just for starting the engine. With all the electron aspects of engines (ignition, injectors, oil pumps, fuel pumps, trim pumps, and electric/hydraulic power steering) significant electric power is needed to operate everything. Totaling the engine’s basic requirements, boaters are often precariously close to (or below) the output of the alternator to the battery at low RPM. Add in basic marine electronics, and the boating experience just reached well beyond the system’s capability. Idling all day offshore as boaters drift or troll may cause the battery to slowly discharge, lowering its total available voltage well below what the engine demands to run properly. In some marine engines, a voltage reading of 10.5 minimum is necessary just to keep the engine up and running. While the battery may have enough energy to turn the engine over and start it, it may not enough firing energy to ignite and supply fuel throughout the electronic injectors.
It’s widely understood that when buying a new or used boat, the generic batteries supplied may not be top-of-the-line. If they seem to do the job, not much thought is invested in them. In warm and tropical climates, daily heat is a major enemy of marine batteries, and can shorten their life considerably. In areas unlike Hawaii or Florida with winter seasons, boats are forced into storage (hibernation) for the winter; how the battery is cared for during that period is also critical to increasing life expectancy. It’s best to keep batteries on a regulated “trickle” charger to maintain charge while not in use, just like an unused car. A battery that is not charged (and kept charged) will harden in cold weather and a cracked case is likely to result.
A battery, like many things in life, if you don’t use it you lose it. Typically, a car battery will outlast a boat battery due the regular use; the battery simply stays charged. When it comes to boats, it’s common experience that a battery’s life is roughly two years. Boaters get a heads-up when the marine battery is about to kick the bucket; that warning being a boat that won’t start or an achingly slow boat. Boaters plug in the charger and the battery miraculously comes back to life like the undead, and you’re back to your routine. Some may assume the battery died due to some electricity guzzling component that was left on while in reality that battery has warped plates, is sulfating, or simply just not able to hold a charge like it once did.
Choose a Marine Battery & Marine Battery Charger Carefully
How can it be determined what’s right as a replacement battery? If the battery’s primary purpose is to start and run the engine, check with the boat engine’s manufacturer (or owner’s manual) to determine the recommended CCA (Cold Cranking Amps) or MCA (Marine Cranking Amps), which will help narrow down your battery search. The manufacturer has put much effort into sizing the battery output to the explicit boat engine prerequisites, so purchasing an inadequate battery completely based on price is begging for trouble. Determine the current battery dimensions when searching for the replacement that will fit properly in the space and/or box. While Group 24 battery is an average battery on the market, Group 27s are larger and aren’t as spread out to supply the power necessary for basic motor function. If there is room enough exists for the larger, better equipped battery, it may be the wiser choice.
For today’s larger marine engines, a 1000 MCA or 750 CCA is typically the minimum recommendation for an engine cranking battery. The letters (MCA, CCA) are short for Marine Cranking Amp and Cold Cranking rating of a battery. CCA is the amount of amps that can be delivered by a lead acid cranking battery, 40 seconds and 0 degrees Fahrenheit. CCA can sustain at least 1.2 volts per cell (12V battery – 7.2 volts). MCA is virtually the same thing, except it’s the number of amps a battery can deliver in 30 seconds at 32 degrees F. It’s inadvisable to crank the engine for 30 seconds (tough on the starter) but that’s the basis for the test rating. Read the ratings on prospective new batteries carefully and get the size recommended, bigger if possible; in this case bigger=better. The higher rated, stronger battery will do a much better job, and will not damage anything it powers. There’s no free lunch in a cheaper battery, so don’t pinch pennies here.
The Difference between Cranking and Deep Cycle Marine Batteries
Concerning electric trolling motors, thrusters, windlasses, or other battery powered accessories that demand greater amounts of electrical current, locate a deep cycle “house” battery. Meant to be where high rates of discharging and re-charging occur often is the deep cycle battery. Constructed much differently than a deep cycle battery is the cranking battery, equip with thicker, heavier plates. The higher, more demanding amperage requirements of windlasses and trolling motors would distort and heat the thinner plates of the average cranking battery. Although the cranking battery may have more thinner plates to give that quick spike of voltage to crank an engine, it is not intended to maintain that high power output for long periods of time. In a tight spot, a deep cycle battery is an option that can be used to start the engine motor, but it’s highly recommended to have a two- or three-battery system separate from the engine battery and the accessory (house) batteries.
The best way to test out the life of your marine battery is to have it tested with a properly with something easy to purchase online, like a ProMariner marine battery chargers remote bank status monitor or at an auto part store where they can “load test” it. Just because your battery has died a few times does not mean that the battery is no longer good. Simple marine battery chargers may conserve the life of your marine battery to the fullest extent. Make sure to pay close attention to the other electrical and charging systems (other than the battery), which may also be causing electrical issues on your boat. The best advice that can be given is to exercise your electrical system as often as you can.