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FIGURE 3: Typical Charger Output Graph (into
batterywithout load)
*Approximately 10 hours maximum at factory setting.
B) Time-Out Circuit
Batteries have a tendency to lose their electrolyte and may
be damaged if they are maintained for long periods of time
in the elevated voltage of the absorption phase. Therefore,
the Phase Three Charger employs a special time-out circuit.
This circuit is initialized each time AC is first applied to
the charger and runs for a pre-set interval before forcing
the charger to go into the float (lower voltage) mode. The
functioning of the charger during this interval is as follows:
If the current demand of the batteries/load falls below 5-15
percent of the charger's output capacity prior to the circuit
timing-out, the charger will automatically switch to the
float mode. (For instance, with model PT-40U, the charger
will drop into float mode at about 2-6 amps output.) If
demand rises to about 10-20 percent of capacity (4-8 amps
with PT-40U, for instance), the charger will return to the
elevated output of the absorption phase. This switching
back and forth between modes may occur until the circuit
times-out (8-10 hours after AC is first applied), after which
the charger will remain at float voltage, until the circuit is
re-initialized by turning the charger off and then on again.
Note: The Phase Three Charger is able to deliver its full
rated output current while in float mode.
C) Gel-Cell/Lead Acid Selector Switch
According to most battery manufacturers, the ideal
charging regimen for gel-cell and wet or flooded lead acid
batteries differs somewhat.
The gelled electrolyte in a sealed battery may be lost
or damaged by high voltage and, once lost, cannot
be replaced as it can with a wet lead acid battery.
Manufacturers of gel-cells usually recommend an ideal
charge voltage which is slightly lower for a gel-cell than
a lead acid battery.
However, when the charger is in the float voltage mode
over lengthier periods of time, gelled electrolyte in a sealed
battery is not susceptible to evaporation, as is the non-
immobilized electrolyte of a wet lead acid battery. This
evaporation can be accelerated by the applied voltage.
Consequently, the ideal float voltage is slightly higher for
a gel-cell than a lead acid battery.
The ideal charge/float regimen has been programmed into
the Phase Three Charger for either sealed gel-cell or flooded
lead acid batteries. Simply make the proper selection for
your battery type via the slide switch on the right side of
the charger. The switch positions are indicated on the front
panel (up for Gel-Cell batteries, and down for Lead-Acid/
AGM type batteries). Use a ball point pen or similar object
to slide it into the correct position. The charger is shipped
from the factory set for Lead-Acid/AGM batteries.
Note: A wide variety of batteries are available which do
not conform to conventional descriptions as "gel-cell" or
"lead-acid". You are advised to consult the manufacturer
of your particular battery as to proper charging regimen,
and use the battery type selection switch setting which
most closely conforms to the recommended voltages.
See the SPECIFICATIONS section for the actual preset charge
and float voltages for each battery type/charger model.
D) Remote Monitor Panel Option
A remote battery monitor (for 12 volt model, PT-40U only) is
available from NEWMAR, model EVM-12-2, which enables
you to monitor when the battery charger is "on" and the
batteries' state of readiness at a glance of two (2) battery
banks only. Red, yellow, and green bar LEDs indicate
the batteries state of charge, and a green "Charger On"
LED is illuminated whenever AC power is connected to
the PT-40U. Flashing red bars indicate when High or Low
voltage is detected. The display has a sleep mode to
conserve power and gives periodic flashing indication of
the battery voltage level even when the boat or vehicle
and the charger are off. In the event battery voltage drops
to a critical level, the display will automatically come
out of sleep mode into full operation to alert the operator.
The EVM-12-2 requires a 22-5 cable (NEWMAR part
number 712-2205-0, sold by the foot). The EVM interface
plugs into the EVM jack on the PT-40U and wires to the
Charger's output.
E) Temperature Compensation Option
Because low battery temperature increases resistance
to charging and high battery temperature reduces
impedance, requiring a lower charge voltage, the ideal
charging voltage will vary depending on the temperature
of the battery's environment when it is being charged.
If a charger has a fixed output voltage which is ideal
at, say 72° F that same output may cause a battery
charged in consistently high temperature environment to
be overcharged, resulting in excessive loss of electrolyte.
Conversely, if the batteries are in a consistently cool
environment, they may be chronically undercharged,
resulting in sulfation of the battery plates. Either of these
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