Most boats under 50 feet in length have 12-volt electrical systems. Many boaters that are seasoned can’t tell you a lot concerning the batteries they will have on board, let alone charging systems and their batteries operate. Take my pal Jeff – an engineer by a seasoned boater and trade. Among the two 12-volt batteries on his 30-foot sailboat was nearing the conclusion of its life. As soon as I asked him what type of battery he was picked to replace the old one, he said Oh, a cheapo Smart cell that was wet.” Certainly driven by short-term economics, my buddy might not have understood that batteries using the same charging system need to be replaced in sets.
There’s a lot to learn about marine batteries. I’ve written before in Layup Tips, but I understand a primer on batteries will be useful. Modern day conveniences including cell phones and laptop computers using lithium-ion batteries have brought substantially to layout and the wisdom of batteries since Gaston Plante initially devised the lead-acid battery in 1859. Nevertheless, marine batteries, particularly the wet cell type, are in the comparative Dark Ages of battery layout.

They can be purpose built, and their internal arrangement will represent their use—starter, heavy-cycle, or double-function—as well as their limits. For example, a battery made for starting your engine will usually have significantly more internal plates closer together, providing more surface area to give that higher, one time discharge needed in powering a starter motor, but Won’t be of the same quality in the long, steady discharge that deep-cycle batteries, with thicker active plates and higher antimony concentrations, give. Deep-cycle batteries may be fired from 50 to 80 percent and regain readily, while beginning batteries don’t enjoy to be fired more than 50%.


Compound Types:
Marine batteries are offered in three compound types: Flooded, Gel, and Absorbed Glass Mat (AGM). Regardless of chemical kind, they’re rated by energy output signal, usually expressed as ampere hours, and categorized by just how many charges (cycles) the battery probably will resist in its life. Lifespan and the outcome will usually order cost. The number of batteries best suited to your boat, chemical sort, and the use is determined by the sort of boat, the way you use it, as well as your budget.
Flooded Batteries: Flooded or Wet batteries following Plante’s design will be the most economical and most frequently occurring form of battery found on boats. They make use of a reservoir of liquid sulfuric acid to behave as a pathway between lead plates. This electrolyte compartment to allow the gas escape outside the boat and creates hydrogen and oxygen when the battery has been charged. Due to outgassing and the heat during charging generated, flooded batteries need regular review and topping off with distilled water. They self-discharge at an increased speed (6% to 7% per month) than AGM or gel batteries, and so need offseason charging. Wet cells have to be set up within an erect position (hard to preserve on boats), nor take high levels of oscillation (common on boats). The great news is that used batteries flooded batteries handle overcharging than gel and AGM batteries, and are 98% recyclable. Wet-cell batteries are also, as my buddy Jeff did understand, significantly less expensive about the other kinds.
Gel Batteries: The gel” that is “ is a composite of pure water, fumed silica, sulfuric acid, and phosphoric acid. The gel prevents escapes in the event the battery is inverted and is fairly viscous, or the case is damaged. Charging does cause a little bit of oxygen and hydrogen to be created in the plates, but the pressure within the cells joins the gases to produce water, so they’re called “recombinant” batteries. This keeps the battery due to charging from drying out. Gel batteries charge in a lesser voltage than glass or flooded -mat batteries, requiring a boat’s charging system to be quite carefully regulated to stop high voltage overcharging.
AGM Batteries: Absorbed Glass Mat batteries attribute glass mat separators saturated with acid electrolyte involving the battery’s negative and positive plates. During charging, pressure valves permit recombine together with the hydrogen, creating water and oxygen generated to migrate to the negative plate. AGM batteries have better shock and vibration protection than gel or wet batteries, and so are practically maintenance-free.
AGM batteries also have lower internal resistance, permitting greater starting charge and power approval, and faster recharging than other varieties of deep-cycle batteries. AGM batteries can accept the highest charging current, up to 40% of the amp-hour capacity of the battery, compared to about 25% for the kind that is awash or 30% for the gel—meaning they recharge quicker. Long life, a low 3% self-discharge rate, and exceptional performance make AGM batteries superb dual-purpose batteries for boaters who need dependable heavy and fast starting strength -cycle skill. Needless to say, the quality is matched by the price.
Boaters don’t understand just how much their behavior affects how long a battery continues. A battery that kept and is correctly charged should continue at least three years. By correctly charged, what do I am talking about? Marine deep-cycle batteries charge the most rapid if they’re charged in distinct stages and last the longest, also called the “Ideal Charge Curve.” The quantity of voltage required to “correctly” charge a battery differs in each stage depending on temperature since a battery accepts present when it’s fired. In practice, recharging the batteries the same day they run down, and using a smart charger to modulate voltage in every period will assist you in getting the most from your batteries.
Although expensive, I prefer the AGM batteries for quality along with security motives—but please do unless, in addition, you install an intelligent charger install these. The double-function batteries are an excellent compromise involving the starter and deep-cycle batteries, specifically with just one battery used for both beginnings for boats and for “house” electricity when the engine is turned off. Purchase the batteries that are more affordable as you may necessarily replace them earlier than later if you’re not into appropriate charging and battery care.

How To Charge Your Marine Battery
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