NewMar 12-1800IC Installation & Operation Manual page 15

(refer also to flow chart on page 16):
1) Bulk Stage: When the AC to the charger is first cycled on and significantly discharged
batteries are sensed, the charger responds by delivering a high amount of DC current, at or
near the charger's maximum rated output, in order to rapidly replenish them. It is during
this stage that charging current is maintained at a high level as battery voltage is driven to
the "Charge" voltage limit designated by the Charger Output Selector. Bulk charging contin-
ues until the batteries are at about 80% of capacity, as verified by a sophisticated battery
"gas point detection" circuit. At that point the charger switches to the absorption stage and
the "80 % Charge" L.E.D. on the front panel (and remote panel, if used) will illuminate.
2) Absorption Stage: During this second stage of the charge cycle, battery voltage is main-
tained at the "Charge" voltage level, while output current is delivered to saturate the battery
plates. This takes place at a rate of about 5 % of battery capacity per hour for four hours. At
the end of this four hour period the batteries are fully charged; the "100 % Charge" L.E.D.
will illuminate and the charger output will switch off entirely.
3) Float Stage: In order to prevent battery damage by extended periods of DC current draw
which would normally demand higher voltage as in the first two stages, the charger auto-
matically reverts to a "Float" mode. In this mode the charger is shut off and remains dormant
until any draw on the batteries causes them to fall below 12.5 VDC (12 volt models), 25.0
VDC (24 volt model) or 33.3 VDC (32-volt model). At this point the charger will switch on and
begin to output the float voltage specified in the charts on page 13, while delivering enough
amperage to supply the DC loads. At the same time the "Float Mode" L.E.D. will illuminate.
(Note: While in the Float stage, the charger is still able to deliver its full rated current output,
as load demands.) At the same time a four hour cycle is initiated. If, at the end of four hours,
the batteries remain higher than the voltages specified above, the charger will shut off and
remain off until DC loads again cause batteries to drop below that point, and the four hour
timed float cycle repeats.
The preceding paragraphs briefly describe the charger functions during normal or optimal
charging conditions. However, certain conditions, such as a high load on the batteries during
the charge cycle or a momentary interruption of external AC power during the charge cycle
may cause somewhat different operation, such as charging time-out or charge timer reset.
The Charger Output Flow Chart (FIGURE 5) on page 16 outlines the charging process step-
by-step and the illustrates the charger's response to various influencing factors.
A note regarding the effect of the "load management" circuit on battery charging:
The inverter/charger is equipped with an AC load management circuit which is in operation
whenever the AC source is external. This circuit apportions AC power first to any loads
connected to the output receptacles or hard-wire AC output, then allocates remaining power
to the internal battery charger. Consequently, if large wattage AC loads are operating at the
same time as the charger during initial stages of the charge cycle, reduced output to the
batteries will result, and they may not be fully charged during the normal cycle. If the
"Timed-out: Charge Incomplete" L.E.D. (discussed in the following note) illuminates after 12
hours of charger operation, this may be one cause. Note: Turning external AC off momen-
tarily, then back on again will reset the entire charge cycle.
P.O. Box 1306
Newport Beach,
California 92663
www.newmarpower.com
Phone: 714-751-0488
Fax: 714-957-1621
E-Mail: sales@newmarpower.com
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