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Usually, by the end of October, many of the lakes have “turned over” for the
winter. Morning steam rising from the water indicates that the heat energy
stored in the lake from the long hours of summer daylight is beginning to
return once again to the atmosphere as the water begins its annual slumber
and ultimate renewal. There is perhaps still a little time left for one
final outing, but most – if not all – of you have taken your boats out of
the water and gotten them cleaned out, “winterized” and ready for next
spring’s trek back to your favorite fishing spots. You take very good
care of your boats, motors, poles, reels and other gear inside the boat.
But have you really taken the time to look after one of the most important
pieces of equipment that you have on board – your batteries?
Most of us take our boat batteries for granted, in much the same manner as we do our
car batteries. I used to do that. In fact, I had a car that sat in the
warmth of the garage all winter. I thought that an occasional blast from
a charger would be enough to do the trick. Boy was I wrong. And the
result was a new battery about every other year – until, after a lecture
from my mechanic, I got a little bit smarter about batteries. Not unlike
young children, they require maintenance. Getting the right battery for
the intended task is only part of the story – keeping that battery healthy
with the proper charging and maintenance will ultimately ensure that you
will have the necessary power when you call for it!
Although I have found that the subject of batteries and battery maintenance is a multi-faceted
subject that encompasses many different topics, I am going to limit my
discussion to a few of the most important “basics”. I will briefly
discuss:
Things that will
destroy a battery
There are essentially
two things that will quickly and easily destroy your battery: 1)
undercharging it or 2) overcharging it. The majority of deep cycle and
starting batteries are lead-plate batteries filled with sulfuric acid.
Undercharging them will ultimately cause lead sulfate to accumulate on the
plates – this will eventually destroy the battery because the normal
chemical reaction will be unable to continue. Overcharging the battery
will accelerate the natural corrosion of the plates due to excess
electrons being literally boiled out of the electrolyte. Ultimately, the
fluid boils away and the plates are exposed to the air, which ruins them.
Battery Chargers
Having said those things, it should be somewhat obvious that it is extremely important to
use a proper charger to do the job of recharging your batteries! Most
chargers that are designed to charge you car batteries are not
designed to charge your boat batteries: they just don’t always completely
shut down. And how often do you think that you can remember to unplug
that cheap charger when things “look about right?” From what I have read,
a 3-stage charger – one that will totally shut off when the battery
has reached full charge – is your best buy.
Without all the chemistry and
physics involved, batteries will do best on a regulated diet of amperes
and volts served up in the right amount… and in stages. There are three
stages: 1) bulk, 2) absorption and 3) float. The bulk stage is where a
battery is brought up to about 75-80% of capacity. Absorption is where
the voltage is constant but the amperage is tapered while the battery is
“topped off.” And finally, the float stage is where the voltage is just
enough to keep the battery from losing any charge. I’m sure that you are
aware of this, but a battery can lose – depending on how and where it is
stored – up to 30% of its charge per month – just sitting around
the house or garage! And there are all kinds of things that affect
battery charge and loss thereof (like temperature, humidity, state of
discharge, age of battery, etc); most of us never consider any of them.
Does size really matter? Well… in a matter of speaking – yes! Try to get
a charger that is rated at about 15% of the battery’s amp-hour rating (a
battery with a 200 amp-hour rating would suggest the need for a 30 amp
charger).
Sulfation
Have you ever had a
battery that seems to work well but “dies” much more quickly than
expected? The problem may be a battery that is heavily sulfated
– often the result of only light use (being discharged by only 15% or
so). The sulfuric acid has become concentrated on the battery’s bottom
and sulfate crystals have begun to form. And even though a multi-meter
will indicate that all is well in terms of voltage, the capacity of
the battery has become severely reduced. Sure, the battery will work just
fine, but it will die much sooner than normal. There are certain chargers
that have a setting that will temporarily boost the charging voltage for a
brief period of time, causing a mixing of the electrolyte, and dissolving
the crystals. The process is called equalization and can be done –
depending on the manufacturer – about once a year. But beware: this
should only be done on wet cell batteries; this same process can ruin
other types. And you will need to make sure that you disconnect the
batteries from the electrical system to prevent the higher voltage from
damaging other equipment.
Maintenance
Batteries have come a long way since the 60’s. Back then, most – if not all – wet cell
batteries were dry to start with. In the storeroom of the gas station at
which I worked, there was a large box with a plastic bag filled with
electrolyte – sulfuric acid. I found out it was acid the hard way; in
filling a battery, I once managed to splash the electrolyte all over my
pants. I didn’t realize the power of the stuff until my work pants got
washed. They looked as if I had been shot by a machine gun – the one leg
was nothing but holes! Now there is an incredible variety of batteries
that are available for every imaginable use: marine starting & trolling,
auto, agricultural, industrial). They all have at least one thing in
common: they need to be maintained to some degree – even the “maintenance
free” types. They will lose their electrolyte during normal use and need
to be checked; all need to be recharged. Most of us still use the wet
cell types for marine applications, although there are essentially three
distinct types of lead acid batteries manufactured for marine
applications, and any one type can be designed and built for either
starting or deep cycle applications. These types are flooded acid, gelled
acid, and Advanced AGM (Absorbed Glass Mat). The gelled acid and AGM
types are essentially maintenance free since they are sealed. But because
of this, be very careful when recharging them. They are also more
expensive but do have their advantages. The most important thing for the
flooded acid variety is to keep them full. Top them off with distilled
water whenever possible; minerals in tap water can contaminate the
electrolyte. Keep the terminal clamps clean and free of corrosion; coat
them with anti-corrosion spray or even petroleum jelly. Check connections
and keep them tight; watch for frayed wires and replace them. And for a
few bucks spent at your local auto parts store, a
Battery Hydrometer – used to
check the specific gravity (concentration of acid) is a good investment.
It is a great way to determine if one of the cells is bad. If the
difference in specific gravity is 30 points or more… it’s time to replace
your battery!
Checkup and Storage
Whether or not your boat
is stored for the season in a warm garage or out in the cold, your best
bet is to remove all batteries and bring them inside. A fully charged
battery with a perfect electrolyte level can probably withstand
temperatures down to zero degrees without freezing. But the colder it
gets, the more easily a battery can discharge, and therefore the more
easily it can freeze at higher temps. If even one of the cells freezes,
the battery is shot! Fully charge them about once a month over the winter
and they will be ready when you are in the spring. Try to keep them off
of concrete floors is possible and cover the terminals to help prevent
discharge. The last thing you want is a dead battery on the launch ramp
on opening day, or a dead trolling motor battery.
With summer now officially here, I hope that most of you have either fished the opener
somewhere or are, like me, chomping at the bit to head to the lakes once
again. Make sure to check your batteries before you head
out. And when next October rolls around, you will perhaps remember a few
things from this article and make sure to take proper care of those very
important pieces of equipment: your batteries. See you
On the Lake!
R. Karl
rkarl@onthelake.net
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This 15 amp on-board charger is perfect for boats with 1 battery
on-board. When the battery is fully charged the charger goes into
maintain charge mode. The charger is programmed to monitor the battery
constantly and has a built-in digital Voltmeter/tester. |
