Curriculum Samples

Batteries

Batteries

I originally had batteries under the Seasonal Maintenance and Checks and Before You Boat sections; but given the nature of batteries and their associated challenges, I decided to separate the topic of Batteries into its own section.

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Batteries are one of the many maintenance items that should be inspected and maintained on a regular basis. For the purpose of this document, there are two main types of batteries; wet cell, the battery that you have to add distilled water to on a frequent basis; and gel cell, the kind of battery that is typically labeled “maintenance free.”  Additionally, there are two main purpose types of batteries; a cranking battery, used for starting the vessel’s engines; and a deep-cycle battery, to run all the electrical components.

 

Cranking Battery Characteristics

In simplest terms, the cranking battery is a designed to provide a lot of power in a very short time.  Power to start an engine.  By design, the power in a wet cell will discharge rapidly; and an alternator is needed to keep the battery charged.

 

Deep-Cycle Battery Characteristics

In simplest terms, the deep-cycle battery is a designed to provide a discharge over a longer period.  Some deep-cycle batteries can produce enough amps (power) to start a boat motor; but it’s not recommended unless the battery is designed to do so.  Doing so will shorten the overall battery life; and sometimes simply not have enough “umph” do start an engine. Deep-cycle batteries are for the use of everything else electrical on the boat.  Radios (that get used all day}, gauges, lights, pumps, electrical components that don’t need a burst of power; but rather require a smooth flow of electrical current over a long period of time.   Your mobile smart device is an example of a deep-cycle battery.  And like a mobile device battery, it works best by being charged all the way down; then, charged all the way up; or in other terms a complete charging “cycle.” And because it best to discharge all the way, that is where the term “deep” is implied.

 

Difference Between a Marine Battery and a Car Battery

Question: Do you know the two main differences between an auto battery and marine battery?  

And, can you use a car battery in place of marine battery?

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Answer: 

The main difference between a marine and auto battery is that a marine battery contains thicker internal lead plates.  These thicker plates allow the battery to discharge over a longer period. Additionally, there are many different sizes and configurations, and the sizes typically include thicker plastic covering due to the corrosive environment and the all the bouncing around that comes with being on a boat. 

 

The other major difference is the electrical connection terminals on a marine battery.  The terminals will have threaded-bolt posts along with the standard electrical post that you would see on a car battery.  Many boats’ main electrical connection to the battery has a large eye-wire connector that goes over the threaded bolt terminal much like a washer goes on a bolt. Then the eye-connector is secured with a washer and nut.

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Another important difference is the battery's operating characteristic. An auto battery is a cranking battery; plain and simple.  A marine battery can be a dedicated deep-cycle battery for use to run all the electrical components or it can (and often is) a hybrid having characteristics of a cranking battery (for engine start) and a deep-cycle battery for running the radio all day when the engine is turned off and not charging the battery with its alternator. 

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Marine batteries are freaking expensive! 

 

So, have I been known to buy a battery that is built for an automobile over one that is designed to work in a marine environment.   YES! 

 

Batteries exposed to Florida’s hot and corrosive climate typically will last about 2-3 years.  Same applies to automobile batteries. If the physical size of the battery and the cranking amps on the manufacturer’s plate matches what is needed to start the motor, I will typically purchase a hybrid deep-cycle/cranking auto battery to save money.  Additionally, maintenance-free gel cell batteries are more expensive and since the batteries typically will last only a couple of years, why spend the extra money for maintenance free. 

Last, if the auto battery doesn’t come with marine threaded post connectors (which they never do) Amazon sells marine post conversion kits.

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Maintaining a Wet Cell Battery

Wet cell batteries use distilled water to assist with charging and performance.  A battery should be filled “completely” after it is completely charged.  You inspect the water level before charging and make sure there is just enough water to cover any exposed plates. After charging, add enough water to bring the level to the bottom of the vent, about ¾ of an inch below the top of the cell.  Do not over fill with water or you run the risk of the water/acid solution spilling out and damaging the battery.  Ordinary tap water should not be used because it may contain an excessive number of impurities that will degrade battery performance.

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Maintaining a Maintenance Free Battery

In the battery’s description is states maintenance free.  Outside of looking for physical wear, tear, damage, and or terminal or wire connection corrosion, there is little that needs to be maintained on a maintenance free battery.

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Battery Usage and Troubleshooting

Every boat built under American Boat & Yacht Council (ABYC) standard construction requirements will have 2 batteries for redundancy.  Located in the boat’s main electrical distribution panel is a battery switch, typically a big red knob with part of the circle knob shaped into a point.  The typical settings are OFF, 1, BOTH (or ALL), and 2.  Larger boats, will often have additional batteries (controlling different aspects or purposes) and their switches will be a similar knob switch that has simply ON/OFF positions.  Additionally, the battery and electrical system will serve a main purpose, e.g., one battery for port engine starting and operation, one battery for starboard engine, and one battery to run all the electrical components such as marine electronics, or lights, pumps, etc. often referenced as “house battery.” 

 

 

 

 

 

 

 

 

 

 

For the purpose of this document, I am covering the standard battery configuration of a small vessel two-battery system. 

 

QUESTION: Which setting is better for boat operation: Running the switch on setting “1,” running on setting “2,” or running on the setting “All.”

 

Before I answer, here is another question:  Do you know how your boat charges the battery when you use the boat all day?  A boat’s batteries are charged using an alternator on one or both engines.  An alternator is an electrical device on the motor itself that turns as the motor turns creating a current that is fed back into the battery keeping the batteries at an acceptable level of charge.  There is some semi-sophisticated magic within this battery charging circuit to ensure the engine alternators do not over charge the batteries.  This semi sophisticated circuitry prevents overcharging and will turn off the charging circuit off when the battery has reached an acceptable charged voltage level.  Overcharging a battery is dangerous and is never recommended as it can lead to a shorten battery life, permanent battery damage, and in rare cases the battery can explode and cause a serious fire and injury.

 

So, which answer did you come up with; 1, 2, or ALL? 

 

First-time boaters and boating novices think it’s better to run on both…MORE POWER.  But the truth is your 2-battery vessel is designed to work on one battery, not two. The second battery is for redundancy; a just-in-case when the primary battery fails.  The secondary battery is a backup to get you home safely.  

 

QUESTION: Do you know what happens when you use the ALL setting on your battery switch? 

 

The electrical needs of the boat; engines, radio, lights, gauges, pumps, everything electrical on your boat is now being run off on BOTH batteries.  This usage may drain the batteries a little slower, and it’s certainly not equal.  Meaning, both batteries have used their charge and typically one battery is a lot less charged than the other one.

 

QUESTION: Do you remember that I told you about semi sophisticated circuitry prevents overcharging? 

 

When your battery switch is set to “ALL” this charging circuitry will read the combined voltage in both batteries (as one battery); makes sense since an “ALL” setting electrically connects both batteries to everything at the same time. However, when the alternator senses a voltage from the stronger (more charged battery) the charging circuit powered by the alternator shuts off (to prevent overcharging) when the acceptable voltage is reached.  Remember the circuitry doesn’t see two batteries it always sees one.  So regardless of the charge state of the second battery (the weaker one) which quite frankly could be almost completely dead, the alternator will charge the stronger battery and the weaker battery will be completely ignored.  And it never fails, the moment you need the second battery, you turn the switch, and the battery is DEAD.

 

QUESTION:  So, I’ll ask the question again: Which setting is better for boat operation: Running the switch on setting “1,” running on setting “2,” or running on the setting “All.”

 

ANSWER: Either 1 or 2; and never ALL.

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Have you ever heard the phrase “use it or lose it?”  Boats are designed to be used, not sit. Worse thing you can do to a boat is not use it.  Same with batteries.  A good practice to get into is to alternate usage of a two-battery system.  Each time you go out, simply switch to the battery “you didn’t use last time” and the batteries will be used frequently and always be charged.

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QUESTION: Then why did manufactures include an “ALL” setting on the battery switch.

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ANSWER:  If you used your boat all day; and part of that day was anchored at the beach listening to the radio, turning on lights, you left your marine radio on or GPS, your battery is slowly discharging, and the engine is not on to keep the battery charged.  When it’s time to leave you attempt to start your engine and the engine makes a clicking sound, one-click sound, or no sound at all, you have a dead battery.  The “All” Setting will use both batteries at the same time to give the electrical system a boost for a “jump” so long as the other battery has enough charge.  Once the engine is started the charging circuit will begin to charge the batteries.  If there wasn’t an “ALL” setting, there would be no way to jump the battery.  And remember, once the boat is started, make sure you put the switch back on the dead battery; otherwise, it won’t charge.

Common Battery Issues

Common Battery Issues

The top two issues with electrical problems related to batteries are 1) the battery doesn’t have enough charge to perform the intended job, e.g., engine won’t start or voltage so low, the electrical component will not turn on. 2) The electrical connection between the battery and the boat’s electrical system is not making a good connection.

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The number 1, number 2, and number 3 reasons a battery is dead on a vessel?   Someone left the battery switches on, or the battery didn’t charge.  Additionally, always ensure after boating that you manually turn off the vessel’s batteries via the main battery switch.  Any load on the battery, even a trickle of current, will drain your batteries to the point they won’t perform by the next day.

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Boats used in salt water are sitting in an environment that attacks metal. From a metal point of view, your boat sits in a big tub of acid.  The salt air is also corrosive and over time, your electrical connections will become corroded and loose the connective properties between the wire connection and the electrical device it is connected to.  Annually, you should inspect all major wire connections, specifically the connections to the battery and bonding system.  A wire brush (to clean) and a marine grade dielectric grease are recommended on all major electrical wire connections’.

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When a boat has electrical problems, and you have determined the batteries have ample charge, the issue most of the time is related to bad electrical connections, either due to poor installation or terminal corrosion. Keep your electrical connections clean.

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QUESTION:  Do you know how to tell if you have a bad/dead battery?

 

ANSWER: There are two ways.  1) You can remove the battery and take it to a local auto parts store, and they can test the battery for you.  2) If you have your own DC voltage meter or multi meter, you can measure the voltage yourself.

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Most small/medium boats work off a 12 V DC (direct current) battery.  Very similar to what is installed in your car. A battery (and a battery charge level gauge) works off the available battery voltage.  A fully charge 12-volt DC battery will read about 12.6 volts when it is fully charged.

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If battery that will not accept a charge, can’t charge above 12.3 volts, or reads 10 volts (or lower) is most likely bad and needs to be replace.   Wet cell batteries that have gone dry (or very low water levels) will accelerate the battery’s usefulness and cause it to go bad within months.  Typical battery-life is about 2-3 years in warm climates.

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Believe it or not, on many boats there are devices that are always connected to the batteries even when the battery switch is turned off.  For example, if your boat has bilge pumps, you want the pumps to kick on in an emergency.  If these pumps were part of the battery switch circuit and the switch was turned off, the boat could fill up with water and sink. More importantly, if your batteries were dead and incapable of running a bilge pump, your boat would sink.  And on this topic, the float switches that control electrical flow to the pumps are automatic.  Meaning the pumps will not arbitrarily turn on unless there is water in the bilge (or in rare occasions a bad float switch).  Chances are you will know when you’re taking on water and when the bilge pumps turn on; the automatic nature of the bilge pump addresses rainwater when the boat is just sitting or other factors that cause the bilge to fill up with water.

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Boat Max Capacity and Weight Distribution

A boat's capacity rating defines how many people or how much weight the boat can safely hold in good conditions as determined by the boat’s manufacturer. This rating is typically displayed on what's called a capacity plate that's mounted in the boat, either by the helm or on the transom.

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Federal law requires capacity plates on boats smaller than 16 feet in length, but the National Marine Manufacturers Association requires plates on all boats less than 26 feet in order to be NMMA-certified.

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Boat Capacity Calculator

If your boat doesn't have a capacity plate, you can calculate the number of people you can safely take onboard using the following equation and calculator.

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Vessel length (ft.) multiplied by vessel width (ft.) divided by 15 = max capacity of persons

 

21 X 7 = 147 | 147 ÷ 15 = 9.8 or 10 persons

 

Question?  If your boat had a maximum passenger rating of 8 persons; could you legally take 9 or 10 people on your vessel?   Technically, the answer is “yes;” you could.  It's not illegal to exceed your capacity rating, but it's not smart!  That is because the passenger capacity is merely a guide for your boat’s total capacity; and the capacity depends more on weight than the number of people.

Note: Most boat manufactures define an average person’s weight as 150 pounds and formulate their max capacity based on that number.

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Boat maximum capacity is about weight, not the max number of people on your boat. If you are planning a full day out on the water, you’re going to take supplies, provisions and gear with you to make the day as enjoyable as possible. If you invite people to enjoy your day of boating, they are going to bring stuff too. You’ll want to make sure the boat has plenty of fuel.  Don’t forget those coolers with those 20lb bags of ice. The point is… Everyone that steps on your boat along with what they bring is ticking down the boat’s maximum capacity weight. Additionally, your boat’s weight capacity must include the what is in the boat’s fuel, fresh water and sanitation tanks, and all the items you permanently or semi-permanently keep on the boat that you brought on since you owned it; and not to forget all the aftermarket items you installed on the boat since you owned it.   

Why is weight on a boat so important?  Overloading your boat, either with too many people or too much weight, makes your boat highly susceptible to swamping.  If a boat’s max weight is exceeded, the boat will sit lower in the water leaving it extremely vulnerable.  All it takes is a small rogue wave or swell, a passing boat, bad weather or some other condition where the water can instantaneously spill into the boat adding even more weight and swamp and eventually sink your boat.

 

Weight Distribution

Weight distribution starts with the center of gravity. The boat’s center of gravity is the point where downward gravitational forces focus. The center of buoyancy is where the upward floating forces focus and should always line up vertically under the boats center of gravity at rest.

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On almost any plaining hull the rule-of-thumb on the location of your boat’s center of gravity and buoyancy is 60 to 65 percent aft of the bow.  Having the center of gravity this far aft, helps plaining boats get on plain quickly, but makes the boat more sensitive to weight issues.

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You should make every attempt to have the weight you bring on your boat at or very near the boat’s center of gravity.  However, most of time that’s not often practical.  But know this; adding weight in the wrong place will alter a boat’s natural center of gravity and effect the boat’s buoyancy.

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Do you ever wonder why manufactures put an engine motor trim on their boats?  Trimming your boat engine is about correcting improper weight distribution between bow and stern.  Trimming the engine up redirects the propeller thrust and raises the bow; and when weight is at your stern, keep the engine trimmed all the way down.

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Lateral weight distribution is equally important; and especially sensitive with V-shaped hulls.   When loading your vessel, distribute the weight as equally (port and starboard) as possible.   If you can’t properly distribute weight, attempt to compensate by putting larger passengers opposite of heavy items.

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Some boats come equipped with trim tabs.  Trim tabs can compensate for listing problems as a result of lateral load problems.  Trim tabs like motor trim, will allow you to compensate most listing problems related to poor weight distribution.

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