Raytheon Beech Baron E55 - Page 609

Raytheon
Aircraft
Company
BARON
55
AND
58
SHOP
MANUAL
ELECTRICAL
LEAKAGE
CHECK
The
self
(internal)
discharge
rate
of
a
vented
nickel-cadmium
airplane
cell is in
the
order of
C/1000
when
fully
charged.
C in
this
formula
represents
capacity
in
ampere-hours.
This
is
about
25
ma
for
25
ampere-hour
batteries.
The
only pertinent
measure
of
external
leakage
is
the
rate
of
discharge
caused
by
the
leakaae.
The
rate
is
significant
only
when
it
approaches
the
rate
of internal
leakage.
Therefore,
external
leakage
need
he
considered
excessive
only
when,
an
ammeter
shorting
the
battery
positive
or
negative
terminal
to
the
battery
case
indicates
25
ma
or
more.
Any
current
less
than
the
preceding
limits
indicates
a
magnitude
of
leakage
that has
a
negligible
effect
on
battery
pe~ormance.
Perform the
following
test to
determine
if external
leakage
is
sufficient
to
necessitate
cleaning
the
battery.
Set
the
range
selector
of
a
multirange
ammeter to
the
500
ma
scale
or
higher (a
low
cost meter
is
recommended
to
preclude
possible
damage
to
an
expensive precision
meter).
Connect the
positive
terminal of
the
ammeter
to
the
positive
battery
terminal
and
the
negative
ammeter
terminal
to
the
battery
case.
Decrease the
ammeter
current
range
to
obtain
a
readable
value
of
current
and record the value. Perform the
same
measurement at
the
negative battery
terminal
by
connecting
it
to
the
negative
terminal
of
the
ammeter
and
connecting
the
positive
terminal
of
the
ammeter
to
the
battery
case.
If
the
current
reading
at
either
terminal is
more
than
25
ma,
the
battery
should
be
cleaned.
This
test
should be made
again
after
the
battery
has
been
completely
cleaned and
charged.
If
the
current
measured
is
again
more
than
25
ma
it
may
be
assumed
that
one
of
the
cells
has
a
seal
leak.
That
cell
may
be
found
by
measuring
connector-to-battery
case
voltages.
The
lowest
voltages
will
occur
at
the
connectors
on
each side
of
the
defective
cell.
A cell
found
leaking
in this
manner
should
be
replaced.
CAPACITY
CHECK
a.
Discharge
the
battery
at
a
rate
of
5.0
amperes
until
an
average
voltage
of
one
volt
per
cell
is
reached.
Measure
the
time
required
for the
battery
to
reach that
discharged
state.
Any battery
that
discharges
to
one
volt
per
cell
in
84 minutes
or
less
should
be
given
another
reconditioning (deep)
cycle.
b.
After
the
second
reconditioning cycle,
recheck the
battery
capacity by
discharging
at
the
rate used
in
step
a.
Measure
the
individual
cell
voltages
after
84
minutes
of
discharge.
If
any
cell is below
one
volt,
replace
it.
E21
SECTION
13
Dec
31103Pagefl