Know How: Batteries

Author:
Publish date:

Given the ongoing proliferation of electronic equipment and gadgets like watermakers, autopilots and electric winches on modern sailboats, it’s little surprise that batteries have become increasingly important. Typically speaking, marine batteries are 6- or 12-volts and are used as cranking batteries to start an engine, as deep-cycle batteries for house loads or as dual-purpose cells.

optima-bluetop31_top

Cranking batteries are typically lead-acid and have many thin lead plates to expose maximum surface area and produce maximum power in short bursts in order to start a boat’s auxiliary engine. These batteries are recharged via an alternator once the engine is running.

Unlike cranking batteries, deep-cycle batteries are designed to service smaller loads over a much longer period. These “house batteries” are built using a variety of technologies. The most common lead-acid batteries are wet cell (or flooded), gel cell and absorbed glass mat (AGM).

State-of-the-art lithium-ion batteries can also be used to handle large capacities and are capable of withstanding many deep-discharge cycles. House batteries typically have fewer (but much thicker) lead plates than starting batteries and are available in capacities of 25AH (amp hours) and 225AH. They are also often wired together to create a bank of batteries with much greater capacities. Look for batteries that meet your anticipated power needs and offer the most charge cycles at 50 percent discharge. Also, be sure that your entire house bank is comprised of a single battery type—never mix battery types (or old and new batteries), as they will have different charge and discharge rates.

Dual-purpose batteries used to start an engine and service house loads are targeted toward small boats that only have space/weight accommodation for a single battery. These provide a reasonable amount of starting power and cycling capacity relative to their size, however, they are typically not suitable for extended cruises. 

Photos courtesy of (from left) Optima, Mastervolt, West Marine

Related

albintoilet

Gear: Albin Pump Marine Toilet

Head Start Is there room for a new marine toilet? Albin Pump Marine thinks so, having just introduced its line of Swedish-built heads—ranging from compact to full-size models—to the American market. The toilets feature vitreous porcelain bowls and either wooden or thermoplastic ...read more

07n_45R2699

Multihull Sailor: Classic Cats

If you’re looking for a decent sub-40ft cruising cat, you have few choices when it comes to new-boat offerings. It is a well-known fact that the multihull market has taken off in a way very few could have predicted. Despite Hurricane Irma’s recent destruction of a large part of ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com Thanks a bunch  This scene is very calm and seamanlike. No frantic rope throwing or shouting. As he passes the line to the gent on the dock, the crew on the boat says, quietly and clearly, “Would you ...read more

mcarthy-and-mouse

Experience: McCarthy and the Mouse

Sitting at the helm in a light breeze, my arms crusted with a fine rime of salt, my skin so dry I’d lost my fingerprints, I heard a clatter and a curse from below. There were only three of us a thousand miles from shore and only one on watch at a time. Usually, the off watch lay ...read more

2018-giftGuide

2018 Holiday Gift Guide

Brass Yacht Lamp Does someone on your gift list spend the whole winter missing the warm days on the water? Let them bring a little bit of nautical atmosphere home with this new lamp from Weems & Plath. The glass enclosure means the flame cannot be blown out even by ...read more

image001

Opinion: On Not Giving Up Sailing

E.B. White was 64 when he wrote his now-famous essay “The Sea and the Wind That Blows,” which begins as a romantic paean to sailing and then drifts, as if spun around by a pessimistic eddy of thought, into a reflection on selling his boat. Does an aging sailor quit while he’s ...read more

1812-JeanneaueNewsVideo

Jeanneau Sun Odyssey 410

Designed by Marc Lombard, the Sun Odyssey 410 shares much in common with her older siblings including of course, the walk-around deck. Other features that set the 410 apart from other models being introduced this year include the 410’s “negative bow” shape allowing for a longer ...read more