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10-18
BATTERY
ELECTRICAL SYSTEMS
(294)
If
t
erminals are
tight and
cables are
apparently
in good
condition,
it is
advisable
t
o
t
est
them
with a
low-reading voltmeter
to
det ect
any ab-
normal
internal resistance.
Figure 10-7-Testi
ng Battery
Cables and Connections with
Voltmeter,
Ammeter,
and Rheostat
b
.
Testing Battery
Cables
and Terminal
Connections
with
V
olt m ete r ,
A
m m e t e r,
and Rheostat
Ba ttery ca bles and t
erminal connections may
be
t
ested with
equipme nt com pr is ing a volt-
meter (5
volts minimum), ammeter of 300 or
more amperes
ca pac ity, and
carbon-pile rheo-
st a t
having
a minimum ca pa city of
300
am-
peres
con ne cted in
series
with
the ammeter.
This m
ethod
is
preferr ed
to use of
voltmeter
onl
y
(subpar.
c
below)
because
the
desired
load
is
obtained
without cranking the
engine.
1.
Adjust rheostat
t
o provid
e
maximum
r
esistance ("OFF"
position)
.
2. Con nec t
ammeter positive
(
+)
lead t
o
battery
t
erminal
stud on cranking motor sol
e-
noid
switch
.
Conne ct ammeter n
egative
(
-)
lead
to on
e side
of
rheostat
and connect other
si
de of rh
eostat
to ground on engine, prefer-
ably at
point where
battery ground strap is
attached.
In
the instrument
shown in figure
10-7 the a
mme te r
a
nd rh
eostat are
connected
in
se
r ies
inside the
case.
3.
Con ne ct volt me ter negative
(
-)
lead
t
o
battery
t
erminal
stud on solenoid switch. Use a
prod with volt meter
lead,
if
necessary,
to in-
sure direct
contact with the terminal stud. Do
not connect to th
e ammeter
lead
clip .
Attach a
prod to
voltmeter positive
(
+)
lead
and apply
the
prod to
center
of battery
positive
(
+)
post
(fig
.
10-7). Make
sure
t
hat
clips of voltmeter
leads
have
clea n m
etal contact
with
prods.
4.
Adjust rheostat
until
a
mme t
er
reads 300
amperes,
immediately
read volt meter,
then
tu
rn
rheostat t
o
starting ("OFF")
position
t
o
avoid
excessive dra in on
battery. Voltage
drop across
battery
positive cable
and t
erminal connections
should
not
exceed
¥t
o
volt.
5.
Connect
volt me te r
posit ive
(
+)
lead
t
o
ground on engin e.
Attach prod to
volt met er
negative
(
-) lead and a
pply
prod
to
center
of
battery
negative
(
-) post . Voltage
drop
across
the
battery
ground ca ble
a
n d terminal
connec-
tions should not exc
eed
¥to
volt.
6. A r
eading
in exce ss of
YIO
volt when
testing eit he r
battery
cable indicates excessive
resistanc e
in ca ble or conn ect ions.
Clean a
nd
tighten ca
ble t
erminals (subpa r. d, below) and
r
ech eck fo
r voltage
drop .
If
voltage
dr op still
ex
ceeds
~)
o
volt
re
pla ce
ca
ble w
ith a genuin
e
Buick
ca
ble
to
ins u re
a
mp le ca
pacity.
Figure
10-8-Testing
Battery
Cables and Connections with Voltmete.
c.
Te
sti ng Ba" e r y Cables
and
Terminal
Connectio ns
w
ith
Voltm
e t e r, W
hile
Cranking Eng ine
If
equipment
is not available for testing
cables and connections as
described a
bove, a
test may
be
made with a
low-reading
volt m et er
while
cra nking
t
he
engine.
1. Gro und the p
r im ary
terminal
of
distrib-
utor
with
a
jumper wire
so that engine can
be
cranked without firing.
2. Connect
negative (
-)
lead of volt m et er
to t
he
battery terminal stud on cranking motor
sole
noid
switch.
Attach a prod to positive
(
+)
lead of voltmeter and apply the prod to
center
of
battery positive
(
+)
post. See
figure 10-8.
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