[omc-boats] Dual Battery Solution (Long Post)

From: Lee Shuster \(L1hhs\) <lib1@...>
Date: Tue, 21 Mar 2006 11:12:46 -0700

Hi all,


Awhile ago I posted a question if anyone had any "good" dead battery
stories? An oxymoron, if there ever was one, right? Most single-engine
14-to-20-foot boats still come from the factory with a single battery,
just as our E/J/OMC boats did.


But a lot of boat owners are adding additional electrical loads for
navigation, fish finders, trolling motors, even entertainment. It can
all lead to greater risk of starter battery failure. And it's hard to
call a tow truck for a jump start on the water! I don't know about you,
but my wife & family get pretty annoyed with boating when we have such
"little" interruptions.


Well, I wanted to share with you a little-known product & company that I
came across after reading the Boston Whaler forum:
http://www.continuouswave.com <http://www.continuouswave.com/> :


Every so often you find a truly great product with great support and
want to share it with others. Such is the case with the Hellroaring
Battery Isolator-Combiner or BIC-95300B http://www.hellroaring.com
<http://www.hellroaring.com/> Funny name, but great product. (No, I'm
not getting commissions).


I just wanted a turn-key, "no-brainer" solution that keeps a backup
battery fully charged and ready to go without risking damage to the
alternator or running down the starter battery. Traditionally, you can
use bulky mechanical switches and a several battery cables that allow
manual selection of battery 1, battery 2 or both. These require the
operator to remember to manually change the switch every other outing.
It's very easy to forget to change the switch. Leaving it in "Both" can
cause both batteries to run down, leaving you without backup power, just
when you need it the most. The operator must also remember to NOT MOVE
the switch when the engine is running, as damage to the alternator will
occur (yes, some switches do feature alternator field isolation, further
complicating installation and wiring).


Another drawback is these bulky switches and wiring must necessarily be
located in the bilge area, where they may be hard to reach, install and
maintain. They can be susceptible to corrosion and tend to get
"forgotten" or neglected. Another approach, involves installing simple
diode-based battery isolators. These have a significant voltage drops
(usually .5 to .7 volts), which can mean modifying the alternator
regulator or (more commonly) risk undercharging batteries. Yet another
(very expensive) approach involves dual output alternators or multiple
bank chargers.


Hence, my search for a better way to AUTOMATICALLY combine and isolate
two battery banks: The Hellroaring BIC is a very compact (think of a
2-inch high stack of 3" x 5" note cards), all electronic, smart device
that automatically knows when to ISOLATE or COMBINE your starter and
backup batteries based on sensing the alternator or battery charger


The BIC is simple to install even in limited spaces on smaller boats,
like our E/J/OMC's. (I will have some photos to share soon). The BIC can
be left in fully automatic mode, or a remotely located, helm-mounted
toggle switch allows the user to manually choose to combine or isolate
the primary and reserve batteries. If you hear that your primary battery
is cranking your starter a little slowly, simply throw the remote switch
to "ON" and temporarily combine or transfer the reserve power of your
backup battery to your starter.


Placing the remote switch back in "AUTO" will insure both batteries
remain isolated when the engine is shut off. Because the BIC is all
solid-state and completely sealed, there are no relay or switch contacts
to worry about. The BIC units are rated to handle any size
engine/alternator/starter that came on our E/J/OMC boats, up to and
including a 5.7 V8. A nice side bonus is a single-bank battery charger
(solar or AC shore powered) need only be connected to the primary
battery and the BIC (left in its default or auto mode) will permit both
battery banks to be charged by a simple single-bank battery or solar


Hellroaring recommends you use your new or "best" battery (highest CCA
rating) as your backup battery. Then you can rotate into service new
batteries (after a couple of seasons) much like you rotate tires. Its
best if both batteries are of similar construction (lead-acid, gel, AGM,
etc.) As my three-year old Exide wet-cell was very tired, I went with
Optima Blue tops (spiral-cell, AGM). Mike at Hellroaring recommended the
deep cycle Blue Top as the primary and the higher CCA-rated starting
Blue top Optima as the reserve or backup battery.


I might also add that it's a pleasure to find a product and company that
is so well supported and documented. Mike handles all support e-mails
and phone calls promptly and professionally.


In addition, the BIC unit comes with everything you need for a tidy




Also check out excellent installation instructions at:





Lee Shuster

Salt Lake City



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Received on Tuesday, 21 March 2006

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