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V) Application Notes
A) Start Up
1) Before powering up your charger, check for tight electrical
connections to each battery in your system. Switch off any
DC loads on the batteries. Apply AC power. Observe the
DC ammeter on the front panel. This meter displays the
total DC output of the charger, through all banks. It will
give some indication of the overall state of charge of your
batteries. If the meter is reading mid-scale or higher, it is an
indication that the batteries are in a relatively low state of
charge. The charger, sensing this, is supplying high current
to the batteries. If the meter needle is at or near the bottom
of the scale the batteries are at or nearing full charge.
2) Apply a load to the charger by switching on some
lights, a pump, or some other DC appliance. Observe the
charger meter. It should read approximately the same as
the expected current draw of the appliance. As current
is demanded from the battery system, the charger will
automatically increase its output in response to the
increased load demand. When load current exceeds 10-
20% of the charger's rated capacity, the charger will go
into the absorption mode and remain there until current
drops below 5-15% of capacity or until the time-out circuit
cycle is complete.
B) Constant Versus Occasional Use
In general, it is recommended that the charger be left
connected continuously to the AC distribution system so that
it will be in operation whenever AC is available. This will
maintain batteries at peak voltage and will automatically
compensate for the natural self-discharge of the battery
system. When a load is applied to the battery system,
the charger's output will automatically increase to supply
the current which would otherwise draw battery voltage
down. Repeatedly allowing batteries to become completely
discharged before recharging will greatly shorten their
life. Leaving the charger on continuously will prevent this.
While the output regulation of the charger will minimize
battery gassing and water loss, monthly checks of the
electrolyte level (for wet lead acid batteries) are still strongly
recommended. Some water loss is an inevitable aspect
of the charging process, and maintaining the correct
electrolyte level in your batteries is the most important you
can do to assure their maximum performance and long life.
C) Proper Load Sizing
The Phase Three Charger is rated for continuous duty (e.g.,
the PT-40U can deliver up to 40 amps continuously, 24 hours
a day, seven days a week). While the charger cannot be
damaged by overloads that exceed this continuous rating,
excessive load demands may draw battery voltage down
faster than the charger can resupply it. If the battery voltage
continues to drop and the output current is at maximum
while the charger is in service, check to see that your
average DC loads are not exceeding the charger's rated
output. If they are, you may wish to consider adding
another charger in parallel to provide sufficient power
for your requirements. (See section III-E, Multiple Unit in
Parallel Wiring.)
D) Operation with Engine
It is perfectly acceptable to allow the charger to remain
on when the engine is started and while it is running. The
current limit feature of the Phase Three Charger will protect
against any damage due to the high current demands
of the engine cranking. Output diodes will prevent any
back-feed of current into the charger from the alternator
while the engine runs.
As the alternator starts to charger the battery, the charger
output will decrease. When the battery voltage exceeds the
rated output voltage of the charger, it will shut off and stay
off as long as the batteries are in this high state of charge.
If the battery voltage should drop below the charger's
rated output voltage, it will automatically return to service.
E) Operation as a DC Power Supply (stand alone DC
Power Source)
Most battery chargers are not suitable for powering
electronic devices directly, without a battery attached to
the output, as the high ripple and pulsing DC output (i.e.,
rectified AC output) can interfere with the operation of the
device. The Phase Three charger is different. It employs a
circuit that produces an extremely well-filtered DC output.
Therefore the charger is able to power virtually any DC
powered device (within the unit's rating) without the
battery attached in-line (if, for instance, the battery must
be removed for any purpose and AC is still available).
All but the most sensitive DC powered electronic devices
will function as normally as if powered by a battery. In
addition, the current limiting circuitry enables the charger
to handle the high start-up surges associated with inductive
loads, such as DC motors in radar sets.
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