Cell-To-Case Insulation Test; Special Testing - Saft 4579 Component Maintenance Manual With Illustrated Parts List

COMPONENT MAINTENANCE MANUAL
(b)
G.

Cell-to-Case Insulation Test

A breakdown in electrical insulation between the cells and the battery case will result
in a "leakage" current, which over a period of time, can discharge the battery. The
most common cause for the loss of insulation is the leakage of electrolyte from the
cells which can act as a conductor between the cell plates (or terminals) and the
battery container. Because the leakage current can affect battery performance, it is
necessary that it is kept to a minimum.
(1) Set up the analog volt-ohmmeter for a measurement of 500 mA.
(2) Connect the negative lead to the battery container, and the positive lead to the
positive terminal of the battery, then to the positive terminal on each cell.
(3) If while performing the above, there is any deflection of the needle (indicating
a reduction in insulation resistance), the battery should be disassembled fully
and cleaned (DISASSEMBLY, CLEANING, ASSEMBLY).
(4) If, after cleaning and assembly, a leakage current is still indicated by the test
described in steps (1) through (3), one or more cells are defective. Isolate and
replace the defective cell(s) (DISASSEMBLY and ASSEMBLY).
H.

Special Testing

These procedures are to be followed for a new battery that has been stored, a battery
with prior service that does not meet capacity, an in-service battery that does not
regain capacity, and/or a battery with an end of charge voltage <1.50 V/cell during the
second charge.
NOTE:
SAFT AMERICA INC.
4579
The following two results are indications that the battery requires
Special Testing, or refer to Fault Isolation:
1 The time to discharge all cells is less then the minimum time as
listed in Figure 103.
2 The end of charge voltage of any cell was less than 1.50 volts
or more than 1.7 volts.
If three cells are replaced during a service cycle or five cells are
replaced over the life of the battery, it is recommended that the battery
be replaced.
24-31-05
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Jan 30/98