In boating, one of the most important and least understood
systems of your vessel has to be the electrical power source systems. Marine batteries!
Marine batteries are the "heart" so to speak, of any sea-worthy platform
as it pumps life giving electricity and current though the vessel. Obviously this is
needed as the many electronics and other comforts of home on a boat need power to make
them run. As usual, if the heart of any machine is not in tip-top shape and working to
perfection, then things dont get done. Marine batteries come in several kinds and
sizes and as with most items associated with our recreational activity, you get what you
I called on a couple of my battery "experts," namely Wally Werner of Sea
Coast Distributors (516-842-2338) and Frank Regan of Sea-Curity Systems
(516-226-1616) of Lindenhurst. Both of these gentlemen made appearances on my television
show for exactly this subject, marine batteries and heres what I concluded from my
conversations with them
CAR vs. BOAT. One of the most commonly asked questions I receive is,
"can I use my car battery in my boat?" Well, this is one of the oldest
misconceptions in the boating game and the truth is you can use a car battery for your
boating needs, but it certainly wont last very long!! Probably not even several
The real truth of the matter? There is a big difference in the two with the first,
being the location of the lead plates within the batteries. In a marine battery, they have
taken the plates that cause electricity and elevated them so as the boat and battery
bounce around, they dont short out. Secondly, they use a special bonding process, so
as things bounce and fall around inside the battery, things stay put. If you use a car
battery, with the bouncing a boat and battery, take it would soon die out on you and the
last thing we want is a call to Sea Tow.
WHAT KINDS? There are three different kinds of marine batteries for you to
choose from. Cranking Amp, Deep Cycle and Gel Cell batteries. First is the Cranking
Amp battery. This battery is used mainly for starting. The cranking amp battery
uses many plates, close together within the battery, to allow current to flow very quickly
through the battery for quick, powerful starting power and quicker battery recharging too.
Next is the Deep Cycle battery. The deep cycle is used for running your
accessories or allowing the electronics to remain on while the engine is shut down, for
example when on the drift while fishing. The plates within the Deep Cycle battery are
spaced further apart and are larger in surface area, which in turn allows the battery to
discharge at a much slower rate and consequently it will recharge much slower as well. You
can run lights and all other assorted gizmos off this battery.
Gel Cell is the remaining battery type and uses the same type of
technology, that is lead/acid, but only with gel inside. The main advantage to the gel
cell is with the sailor in mind. While most of us have experienced the thrill of sailing,
you also notice the tilt of the boat when sailing. Gel Cells, since they contain gel and
are closed are perfect for this use, because they will not leak water or acid when off
center as on a sailboat. When anything containing a liquid is on its side and takes the
punishing effect bouncing on the high seas gives, you want a battery that will not leak,
such as the gel cell battery. Gel Cell batteries are a closed system of battery, that is
inaccessible to us with no need to check water or in this case gel levels.
RATINGS. All batteries, car or marine come rated for the job they are supposed
to do, namely starting engines & supplying power. Cranking amps is the term used for
"power output," or the amount of power needed for turning over the engine.
Another term, cranking amps, are rated on temperature. Cold cranking and marine
cranking. In cars, or cold cranking, its 0 degrees and in marine batteries its
32 degrees. An amp is a measure of current. The cranking amps needed to start engines in
marine batteries, is less than that required for cars, for obvious reasons. Not too many
of us have to start our outboard or inboard engines in temperatures of 30 degrees or less,
never mind 0 degrees. In marine batteries, the cranking amps needed to start an outboard
engine is greater than that needed to start stern drives or inboards.
Theres also reserve capacity ratings on batteries. Reserve capacity is the
amount of power, rated in minutes, a battery has before draining to a point where the
battery can no longer do its job. A marine starting battery for example may have a
cranking amp rating of 650 amps, but a reserve of only 85 minutes in which you can use
accessories (depends on drain) before the battery is drained of the power needed to do the
job, starting an engine. A deep cycle marine battery may have cranking amps rated at 550
amps, but a reserve of 130 minutes, which translates into less starting power on cold
days, but more reserve time for running accessories with the engine shut down. Next week,
well cover open or closed batteries, setting up your battery system and safety in
OPEN OR CLOSED. When it comes to batteries, you have "open" and
"closed" batteries. Open means just that, it is open and you have accessibility
to check water levels. Closed batteries do not give you this option and usually come with
a little light or "eye" that reads green when good and red or black when no
Remember though, when batteries are recharged via an alternator or other charging
device, they heat up a little and will bubble off (evaporate) some of the water within the
battery, which you can replace (check weekly). With a closed system, when recharging and
heat & bubbling occurs, pressure increases and can cause a problem if over charging
comes into play. I prefer to use batteries with an open system and I think it advisable
when using Cranking Amp or Deep Cycle batteries to use an open
battery system. One in which you can check and add distilled water when levels are low.
This way you get added life from a battery.
Also remember, a gel Cell battery is a totally closed system and while it may charge
better in the long run, but the biggest problem with them is over charging. Gel cells can
only be charged to 14.3 volts and anything over this can cause a rapid breakdown within
the battery. However, gel cells big advantage is quick discharge and very quick recharging
capabilities, and when hooked with a high charge power alternator, can recharge in as
little as a half-hour to an hour.
SETTING UP A SYSTEM. When it comes to setting up a battery system, there is
good, better and best. Smaller boats that only run on one battery, should opt for a deep
cycle as the better choice. Youll still have enough cranking power for starting and
the reserve is longer for running accessories with the engine shut down.
The better system involves two batteries and a battery switch, that allows you to run
on both batteries, or either one individually. On this switch are the words or numbers for
1, 2 or both. In this system, the best scenario is the cranking battery as the starting
battery and the deep cycle battery as the accessory battery. You would start the engine on
the cranking battery, #1 on the switch and when drifting or running accessories
with the engine off, the deep cycle battery, or #2 on the switch. You would then
restart the engine on 1 and continue this pattern until its time to head home. Now
start the engine on the Both (all) switch, which then recharges both batteries at
the same time while underway home.
The best system includes this dual battery system, however we now take it one step
further and install an isolator on board. An isolator is a diode that allows both
batteries to be charged simultaneously without one battery affecting the other. A diode
also prevents overcharging of either or both batteries. An isolator acts as a
"T" valve, in that electricity can flow in only one direction. As
"juice" flows into the batteries upon recharging, when one battery is fully
charged, the "T" valve closes and prevents further charges from entering the
battery, thus preventing an overcharge.
SAFETY. Whenever you install batteries or do any installation of battery systems
yourself, safety is the number one concern. Batteries have pressure and are explosive
materials when not handled correctly. You must always wear some sort of eye protection,
such as safety goggles. For a battery system to work correctly, polarity must be correct.
That is, positive (red) to positive and negative (black) to negative. When connecting your
battery wires to the terminals, always connect the positive (red) last! Just as in a car
battery, connecting the negative wire last, can cause a spark and this spark may ignite
any escaping gaseous fumes from the battery, causing an exploding battery.