LETTERS6 Professional BoatBuilderLETTERStwo DC-DC converters (to charge
smaller AGM batteries), monitoring
software, and the control system. In my
opinion, this approach has paid off many
times over. My vendor (Mastervolt)
“took ownership” for the system. They
played a key role in designing it, select-
ing and sizing its components, and
configuring/tuning the system in opera-
tion. Their technical support was readily
available and extremely valuable. They
were able to take downloads from the
monitoring software or view the boat’s
electrical system operation in real time
if an Internet connection was available.
Their control system enabled software
updates of all components. Many of
these changes have incorporated experi-
ence gained with their lithium batteries.
In my opinion, this “seamless integra-
tion” has been invaluable in enabling us
to focus on sailing rather than watching
our electrical system while trying to sail.
I remain convinced that lithium-ionmechanical means to set belt tension.
I chose a Mastervolt 130-amp, 12V
alternator to stay with the same manu-
facturer for all major components in
my electrical system. The manufacturer
assured me that the alternator would
have no overheating problems, and this
proved correct. Although the external
Mastervolt regulator can be set to moni-
tor alternator temperature, the company
recommended that it be configured to
monitor lithium-ion-battery tempera-
tures, and my system is set up to do that.
I regularly monitored alternator tem-
perature with a handheld IR device, and
the temperatures have never approached
design limits.
Engine-compartment temperatures
did not change significantly with the
new alternator.
I used the same manufacturer for
the lithium-ion batteries, the inverter/
charger, a second large charger, the alter-
nator, the external alternator regulator,the alternator from its original position
to the front of the engine.
High-capacity alternators require sig-
nificant mechanical power to drive them.
My 130-amp, 12V alternator uses about
5 hp (assuming 50% efficiency). This
translates to reducing the engine speed
by 100 rpm on my 100-hp [75-kW]
Yanmar 4JH3-HTE engine. This means
that the installation must use an alter-
nator drive belt that can handle the load.
I chose a 10-rib serpentine belt because
its appropriate crankshaft and water
pump pulleys were readily available for
my Yanmar engine. The 10-rib serpentine-
belt generator pulley was custom-made
by JK Pulley & Manufacturing, St. Louis,
Missouri.
The power transferred through the
belt drive also means that the belt must
be tightly tensioned. My alter nator’s cus-
tom reverse mount has a bolt-and-slider
mechanism to tighten the belt, and I
highly recommend such a robustLetters172-ADFinal.indd 6 2/21/18 8:12 PM