Specifications
MARATHONNORCO AEROSPACE, INC.
NICKEL-CADMIUM AIRCRAFT BATTERIES
24-34-00
Page 103
MAY 10/11
C. Evidence of arcing of burn marks on the power contacts. This is caused when the
disconnect is removed under electrical load.
D. Insert the .385 inch diameter end of the inspection gauge into each power contact to a
depth of .437 inches. The fit shall be snug with a force to remove greater than one (1)
pound. This is to test the resiliency of the power contact to an oversized pin.
E. Insert the .370 inch diameter end of the inspection gauge into each power contact to a
depth of .437 inches. The fit shall also be snug with a nominal force to remove one (1)
pound. This will ensure proper contact to a worn or undersized contact pin.
F. Replace if required.
1.2.4 Voltage Regulator
The voltage regulator should be set at a level consistent with the normal ambient
temperature band and should be set on the aircraft after a start and a few minutes into the
charging period (seeTable 1). Periodic checks to correct out- of-tolerance regulators and
replacement of defective units will reduce the possibility of inadvertent increases in
charging voltage with the resultant rise in charge current and battery temperature and
water consumption.
Recommended voltage settings measured at the battery terminals and applicable to room
temperature conditions, under a known time span of 4 hours are shown in Table 1. (These
are nominal values computed by multiplying the number of cells in the battery by a factor of
approximately 1.5). For voltage regulation at ambient temperature higher or lower than
75°F (24° C), see Figure 3.
Table 1 - Recommended Voltage Regulator Setting at 75°F (24°C)
Number
of
Cells
Nominal
Battery
Voltage
Time
In
Hours
Voltage
Maximum*
Voltage
Regulator
Setting
5
6
2-4
7.5-7.75
7.50
10
12
2-4
15.0-15.5
15.00
12
15
2-4
18.0-18.5
18.00
19
22.8
2-4
28.0-29.0
28.50
20
24
2-4
28.5-30.0
30.00
22
26.0
2-4
31.0-33.5
33.00
* Constant potential charging voltage and time apply to all ampere-hour ratings,
subject only to number of cells per battery