Battery Tech (Part 1)

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[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Boat Batteries The Technical Details[/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Although your boat uses a gasoline engine for its primary propulsion, without ample electricity, that outboard is pretty much out of business. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Let's tackle a fistful of the most common boat battery-related topics. To keep things simple, we'll discuss a single engine boat; however, the principles are similar for multi-engine installations. [/FONT]

[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Boat Battery Applications and Ratings
On most boats, especially those with lots of demanding electrical equipment (trolling motors, aerated/recirculating livewells, washdown pumps, downriggers, full electronics, powerful sound systems), you'll need multiple batteries, a starting battery, and at least one storage battery, or a combination starting/storage battery. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Marine Cranking Battery (Starting Battery)
As the name implies, the cranking battery's sole purpose is to start the engine. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]When you initiate the starting sequence (turn the key, press a button), the starting/cranking battery sends an enormous surge of electricity to the engine's starting motor. After the outboard is running, the engine's charging system sends electricity back to the cranking battery to recharge it. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]The starting battery expends a great deal of energy for a few seconds at a time. A cranking battery is exceptionally strong in the short term; however, it doesn't have an excess of power in reserve, and will fail prematurely if deeply discharged repeatedly. [/FONT]

[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]According to the American Boat & Yacht Council (ABYC), a marine battery must have at least the cold cranking amperage (CCA) required by the engine manufacturer. Cold Cranking Amps is a rating that defines a cranking battery's ability to start an engine at 0 degrees F (-17.8C). This can range from about 250 CCA for an electric-start 25 hp kicker to 750 CCA for a 350 hp mega-outboard. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]You should find cranking battery specs in the outboard's owner's manual Cold Cranking Amps (CCA), Marine Cranking Amps (MCA) and Reserve Capacity (RC). At least one of these three ratings CCA, MCA and RC should be clearly marked on the battery's label. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Prudence dictates installing a dedicated starting battery connected only to the outboard's ignition/starting circuit. If all the boat's electrical gadgets use the starting battery, there is a very strong possibility that you'll hear a sickening "click" when you try to crank the engine after a long day on the water. [/FONT]

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[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Deep-Cycle/Storage Batteries
A storage battery (or banks of multiple batteries) provides the juice to energize all the boat's electrical systems without the engine running. Another name for a storage battery is the "house battery," because, like in a house, it delivers electricity for the lights, TV, air conditioning and other components. On a fishing boat, you can substitute the term "trolling motor" batteries for "house" batteries. [/FONT]

[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]You'll want to use deep-cycle batteries for your boat's non-engine electrical needs. Deep-cycle batteries (or banks of batteries) provide large volumes of power over extended periods of time, can endure extreme discharges and bounce back as good as new after a recharging session. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]A deep-cycle battery has several ratings on its label, but the two you ought to take note of are Amp-Hours (AH) and Reserve Capacity minutes (RC). [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Amp-Hours (AH) quantifies the number of amps a new 12 volt battery can deliver at 80 degrees F (27 degrees C) by multiplying the electrical system's current draw in amps by the time it takes (industry standard is 20 hours) to discharge the battery to 10.5 volts. For example, a battery that can successfully energize a 7 amp load for 20 hours (7 amps x 20 hours = 140 AH) would display a 140 AH rating on its label. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Reserve Capacity (RC) is the number of minutes at 80 degrees F (27 degrees C) that a new, fully charged battery can be discharged under a 25 amp load while maintaining a voltage of at least 10.5 volts. [/FONT]

[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Dual-Purpose Batteries
What if your boat doesn't have enough space for more than one battery? Then you may consider a dual-purpose cranking/deep-cycle battery for your boat. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Dual-purpose batteries excel in the engine-starting arena, and have sufficient reserves for low-demand accessories. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Make sure to check out the label to ensure the battery meets your outboard manufacturer's Cold Cranking Amps specs, as well as the Amp-Hours, to make sure the battery has the intestinal fortitude to feed the electrical requirements of your boat's nav lights, bilge pump, and electronics. [/FONT]
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[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Marine Battery Construction
Boat batteries are available in three fundamental designs: flooded-cell lead-acid, gel-cell, and Absorbed Glass Mat (AGM). [/FONT]

[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Flooded-cell lead-acid batteries contain lead plates (and other components), within a battery case filled with an electrolyte solution. These batteries can be maintenance free or fully maintainable (removable caps to check fluid levels). Install flooded-cell batteries upright, to keep the liquid electrolyte in the battery case where it belongs. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Gel-cell and AGM batteries use Valve-Regulated-Lead-Acid (VLRA) technology for safer, more durable electrical storage. VLRA batteries are sealed lead-acid batteries, except for a small one-way valve that allows internal gases to exit the battery housing when/if these gas pressures exceed the manufacturer's specified levels. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]A VRLA (gel-cell/AGM) battery is often called a "recombinant" battery, meaning that the negative plates capture the oxygen emitting from the positive plates. This suppresses hydrogen production at the negative plates, creating water instead, thus keeping the battery well hydrated. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]A gel-cell is a lead-acid battery in which the electrolyte solution is suspended in a thick jelly-like mixture contained in a sealed case (with a VRLA valve). Gel-cell batteries are spill-proof and maintenance-free. Due to the way the acid/gel mix functions, these types of batteries can be well suited for deep-discharge applications. The properties of gelled electrolyte that make a gel-cell so desirable are also a potential weakness; a gel-cell battery's power drops rapidly below 32 degrees F (0 degrees C). [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]In an AGM battery, absorbent glass-fiber mat separators soak up the electrolyte like a sponge. Encased in a VRLA-valved sealed housing, an AGM battery is maintenance-free and spill-proof; you could conceivably install this battery at any angle, except upside-down. AGM batteries are noteworthy for their consistently high current and power output, even in bitterly cold conditions. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]VRLA batteries - AGM and Gel-cell - are particularly sensitive to overcharging; therefore, use a good constant potential, temperature-compensated, voltage-regulated charger. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Never use a constant current charger on VRLA batteries. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Other Battery Thoughts
The final word on what type/size/rating of battery you must use is in your outboard's owner's manual - for example, Yamaha Marine Group specifies flooded-cell batteries to avert potential overcharging gel-cell or AGM during extend periods of high-speed engine operation. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Resources
American Boat & Yacht Council (ABYC) Standards and Technical Information Reports for Small Craft
http://abycinc.org [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]U.S. Coast Guard Boatbuilder's Handbook
http://www.uscgboating.org/regulatio...gulations.aspx [/FONT]

[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Yamaha Motor Corporation, U.S.A.
http://www.yamaha-outboards.com [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Image Credits
Ranger Boats [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]How Much Battery Do I Need?
Grab your calculator. How much electricity does your boat require? You'll need enough power to start the engine - very important - and sufficient electrical reserves (storage batteries) to operate the navigation lights, bilge pumps, electronics, livewell pumps, trolling motor, and assorted accessories. [/FONT]


[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Battery Warnings[/FONT]

• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Batteries contain sulfuric acid. When handling batteries, use extreme caution[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Wear rubber gloves, safety glasses, and protective clothing while working with batteries[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Electrolyte/sulfuric acid will burn your skin and can destroy your eye[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]If acid contacts skin, wash skin thoroughly with soap and water[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]If acid contacts eye(s), flush aggressively with fresh water and get medical help immediately[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Batteries produce explosive gases [/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Ventilate when charging or using in an enclosed space[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Keep sparks, flames and cigarettes away[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Do not allow any electrically conductive material to contact the positive (+) and negative (-) terminals at the same time (i.e. a wrench accidentally touching both terminals when connecting battery cables) This will short-circuit the battery, creating dangerous sparks and/or causing the battery to explode, resulting in severe personal injury[/FONT]
• [FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]Keep batteries out of reach of children[/FONT]

[FONT=Trebuchet MS, Lucida Grande, Arial, sans-serif]List provided as a sample only. See the instructions that accompany your specific battery for complete list and warnings. [/FONT]