CSP-HMI-3 MD Helicopters, Inc.
MAINTENANCE MANUAL
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96-05-00
The information disclosed herein is proprietary to MD Helicopters, Inc.
Neither this document nor any part hereof may be reproduced or transferred to
other documents or used or disclosed to others for manufacturing or any other
purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright © 1999−2016 by MD Helicopters, Inc.
A. Battery Charging − Normal Procedure
Review Battery Handling
and Servicing Precautions
before performing following charging
operations.
(1). If battery is installed in helicopter, set
master switch to OFF and remove
battery.
(2). Perform Battery Cleaning.
(3). Inspect battery for any damage that
requires battery replacement or repair.
Do not add distilled water to
electrolyte prior to charging,
even if electrolyte is not visible. Electrolyte
level will rise as charging progresses.
NOTE: Following instructions are for charging
with constant-potential method. When
charging by constant-current method, dis
regard procedures in step (4). below and
charge battery according to battery and bat
tery charger manufacturer's instructions.
Charging is normally accomplished with cell
filler vent caps installed. Temperature of
battery may rise during charging.
(4). Charge battery for 30 minutes using
constant-potential charger. Take care
to maintain constant and accurate
charging voltage of 28.0 - 28.5 volts dc
for full charging period. If necessary,
monitor and manually adjust charging
voltage to prevent any drop or rise in
charging voltage.
(5). Switch charger OFF and then discon
nect battery from charger.
(6). Remove filler vent caps and check
electrolyte level. Replenish with pure
distilled water per Battery Servicing
Procedure if necessary; do not over-fill.
(7). Replace and tighten filler vent caps.
B. Battery Charging − Deep Cycling
Procedure
Review Battery Handling
and Servicing Precautions
before performing following charging
operations.
(1). Perform Battery Charging - Normal
Procedure.
(2). Connect a 9-ohm resistance (9-ohm,
200-watt resistor or three 3-ohm,
75-watt resistors in series) across
battery terminals and allow battery to
discharge for approximately 12 hours,
or until battery voltage decreases below
1 volt.
(3). Remove 9-ohm load resistance from
battery and loosen cell filler vent caps.
(4). Charge battery per Battery Charging -
Normal Procedure, until charging rate
decreases to less than 0.03 ampere.
(5). While continuing to charge battery at a
rate less than 0.03 ampere, use an
accurate voltmeter to measure voltage
across terminals of each individual
battery cell. Each individual cell should
be within 0.05 volt of cell voltage,
specified below (Ref. Table 201), for
applicable charging voltage.
Table 201. Individual Cell Voltages − Deep
Cycling
Charging Voltage
(volts dc)
Cell Voltage
(volts dc)
28.0 1.47
28.1 1.48
28.2 1.48
28.3 1.49
28.4 1.49
28.5 1.50
NOTE: Nominal individual cell voltage is 1.25
volts for a normal, disconnected and fully-
charged cell.
(6). Switch charger off and then disconnect
battery from charger.
WARNING
CAUTION
WARNING
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