Boating and Sailing.pdf - Moja ladja

Chapter 20: The Well-Equipped Nautical Toolbox
◆ The “deep-cycle” battery is designed to provide long-term power to low-amp draws
like trolling motors and boat lights. These batteries have thicker plates, which allow
them to survive many complete discharges without damage.
Most batteries of both types are filled with a liquid acid that can spill out if the battery
turns over. Sealed batteries avoid this problem; they cost a little more, but they can’t spill
and you never have to add water.
Gel cell batteries, which replace the liquid with
a thick jelly-like acid, last about twice as long as
conventional acid-filled batteries, but they cost
three times as much. A typical 85-amp gel cell
goes for around $175, compared to about $75
for the same thing in a standard battery. But if
your batteries are in a tough-to-reach spot where
installation and removal is tough, the gels are
worth considering. If you have a big inboard to
crank, you need a really big battery—some of
these develop over 200 amps—and weigh over 120
pounds!
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Marine batteries come in
both high-output versions
designed for short bursts of
power to start the engines,
and deep-cycle models that
produce their power slowly
and steadily and can survive
repeated discharges to near
zero, used to power electric
trolling motors and other
accessories.
(Photo credit: GNB Batteries)
Boat Bytes
One of the most important
“tools” you can carry on
your boat is a spare battery.
When your main 12volt
source dies, a back-up
is a godsend, and having two or
more batteries also splits the
load for many operations, allowing
both to live longer.