Specifications

MARATHONNORCO AEROSPACE, INC.
NICKEL-CADMIUM AIRCRAFT BATTERIES
24-34-00
Page 201
APR 15/06
2.0 ELECTRICAL LEAKAGE
To determine if external leakage is of such a magnitude as to require a complete battery cleaning
set the range selector of a multimeter to the 500 milliampere range or higher.
Place the positive lead of the meter on the positive terminal of the battery receptacle and touch the
negative lead of the meter to any exposed metal on the battery can.
NOTE: Many MarathonNorco batteries are supplied with epoxy coated battery cans and
covers. Where epoxy coated cans are used, current flow may be measured
between the battery terminals and the screws that are used to mount the main
connector.
If the measurement is within the meter limits, connect the negative lead of the meter to the battery
can. Record this current value.
Repeat the above, connecting the negative lead of the meter on the negative terminal of the battery
receptacle and the positive meter lead to any exposed metal on the battery can.
If the above current measurements exceed 50 milliamperes, flush the tops of the cells and dry.
(Reference Paragraph 9.0)
Repeat the above current test on the positive and negative terminals. If the tops of the cells were
cleaned properly and the current measurement is still greater than 50 milliamperes, one or more of
the cells may be leaking. To isolate this cell or cells, proceed as follows:
Using a voltmeter of 1000 ohms-per-volt, or greater, place one of the meter leads on either
the negative or positive terminal of the battery and the other lead on any exposed metal of
the battery can; note the meter reading. If the meter reads negative, reverse the positions of
the meter leads.
Keep one-meter lead on the exposed metal surface of the can and move the other lead
systematically from one cell terminal to another, noting the voltage readings. Voltage
readings will decrease and finally go negative indicating the location of the path and possibly
a leaky cell.
If the cell is leaking, replace the cell or cells. If no leaking cells are found, the leakage path
may be due to electrolyte along the outside of the cells and at the bottom of the battery can,
and the battery must be discharged, disassembled and cleaned. (Reference Paragraph 9.0
and 11.0)