Cessna T188C - Page 310

MODEL
188
& T188
SERIES
SERVICE
MANUAL
c. A188B
AND
T188C
BEGINNING
WITH
18803722
&
BATTERY
HYDROMETER
READINGS
T18803722T.
1. On A188B
remove cover
on right hand
side of
1. 280 Specific
Gravity
100% Charged
fuselage at wing leading
edge for access to battery
1.250 Specific Gravity
75% Charged
2. On T188C
remove
cover on right
hand side of
1.220
Specific Gravity
50%
Charged
tailcone for
access to battery.
1. 190 Specific
Gravity
25% Charged
3
Disconnect
the ground
cable
from the
negative
1.
160 Specific
Gravity
Practically
Dead
battery
terminal.
NOTE
CAUTION
All
readings
shown
are for
an
electrolyte
When installing
or removing the battery
temperature
of 80
°
Fahrenheit. For
higher
always observe
the proper
polarity with
temperatures
the readings
will be slightly
the aircraft electrical system (negative lower. For cooler temperatures the read-
to ground). Reversing the polarity, even ings will be slightly higher. Some hydrome-
momentarily, may result in failure of ters have a built-in temperature compensa-
semiconductor devices (alternator diodes, tion chart and a thermometer. If this type
radio
protection diode and radio
transistors).
tester is used, disregard this
chart. If a
specific
gravity
reading
indicates
that
the
4. Cut sta-strap and
remove cover from positive
battery is not fully
charged, the battery
cable, then
disconnect
cable.
should be charged
at approximately
20
5. Remove battery hold
down bolts and remove
amperes for 30 minutes,
or until the battery
battery.
voltage rises
to 15 volts. After charging,
a
6. Remove
clamp
and remove drain
tube from
load
type tester
will give more
meaningful
battery. results. A specific gravity check can be
7. Remove battery.
used after charging but the
check cannot spot
8. Reverse the
preceding steps for reinstalla-
cells which short
under load, broken connec-
tion, using new sta-strap
on positive terminal
cover. tors between
plates of a cell. etc.
16-12. CLEANING. For maximum efficiency, the 16-14. SERVICING. A battery being charged and
battery and
connections
should
be kept clean
at all
discharged
with use will
decompose
the water
from
times.
the electrolyte
by
electrolysis.
Add distilled
water
a. Remove the
battery in accordance
with preced-
as
necessary to
maintain the electrolyte
level
even
ing paragraph. with the horizontal baffle plate inside the battery.
b. Tighten battery cell filler caps to prevent the When "dry charged" batteries are put into service.
cleaning solution from entering the cells. fill as directed with electrolyte. However, as the
c. Wipe battery cable ends, battery terminals and electrolyte level falls below normal with use add only
entire surface of the battery with a clean cloth mois- distilled water to maintain the proper level. The bat-
tened with a solution
of bicarbonate
of soda (baking
tery
electrolyte contains
approximately
25r sulphuric
soda) and water. acid by volumne. Any change in this volumne will
d.
Rinse with clear water, wipe
off excess water hamper
the proper operation
of the battery.
and allow
battery
to
dry.
e.
Brighten
up
cable
ends
and
battery
terminals
with
emergy
cloth
or
a wire
brush.
CAUTION
f.
Install
the
battery
according
to
the
preceding
paragraph.
Do
not
add
any type
of
"battery
rejuvenator"
g.
Coat
the
battery
terminals
and
the
cable
ends
to the
electrolyte.
When
acid
has
been
with
petroleum
jelly.
spilled
from
a battery,
the acid
balance
may
be adjusted
by following
instructions
pub-
16-13.
TESTING.
The specific
gravity
check
meth-
lished
by the
Association
of American
Battery
od
of testing
the
battery
is preferred
when
the
condi-
Manufacturers.
tion
of the
battery
is in
a questionable
state-of-charge.
However,
when the
aircraft
has
been
operated
for
a
16-15.
CHARGING.
When
the battery
is to
be charg-
period of
time with
an alternator
output
voltage which
ed,
the level
of electrolyte
should
be checked
and ad-
is known
to
be correct.
the
question
of battery
capa-
justed
by adding
distilled
water
to cover
the
tops of
bility may
be answered
more correctly
with
a load
the
internal
battery plates.
The
battery cables
and
connections
should
be
clean.
type
tester.
If
testing
the
battery
is
deemed
neces-
sary,
the
specific
gravity
should
be
checked
first
and
compared
with
the
following
chart.
16-6