Chevrolet 70 Series 1970, Service Manual

Page: 543 / 841

ENGINE ELECTRICAL 6Y-2
BATTERY MODEL APPLICATION CHART (CONT.)
TRUCK SERIES
PART NO. MODEL
OPTIONAL
H M /JM -8 0 ........................................................................ ... . . . 1980974 9H9-974
H I/JI/M I/H N /JN -9 0
(Two B a tte rie s Connected in P a r a ll e l) ............... . . . 1980760 8DR-205
HM /TM -80 (Two B a tte rie s in S e rie s )......................... . . . 1980926 3H-926
D I/F I-9 0 (F o u r B a t t e r i e s ) ........................................... . . . 1980716 4HR-160
D I/F I-9 0 (Two o r F o u r B a t t e r i e s ) ............................. 1980718 7DR-200
GENERAL
On som e vehicles, h ard rubber ce ll covers
a r e fitted over term in a l p o sts of the elem ents. Cell
connectors a re welded between in term ediate te r m ­
inal p o sts of adjoining cells to estab lish a s e r ie s
c irc u it.
The battery shown in figure 1 fe a tu re s a one-
piece cover of hard ru b b e r construction which r e ­
duces the tendency fo r co rro sio n to fo rm on top of
the b attery . The cover is bonded to the case with
sealin g compound that form s an a ir s e a l between
the cover and c a s e . The ce ll connectors p a ss through
sealed holes in cell p a rtitio n s to connect elem ents
to g eth er in the s h o rte s t p ra c tic a l distance (fig. 2).
With the length of the e le c tric a l c irc u it inside the
b attery reduced, the in tern al voltage drop is de­
c re a se d .
The c e lls a r e p ro p e rly filled when the elec-
ELECTROLYTE LEVEL
INDICATOR
Figure 1 —Typical Battery with One Piece Cover
tro ly te level re ach e s the bottom of the " sp lit vent"
at the bottom of the vent well. The sp lit vent is a
visual level fill fe a tu re in the cell co v er. The ele c ­
tro ly te su rface w ill ap pear d isto rted when it con­
ta c ts the 'split vent.
The b a tte ry has th re e m ajo r functions to p e r ­
fo rm on the vehicle:
1. It provides a so u rce of c u rre n t fo r sta rtin g
the engine.
2. It a c ts as a s ta b iliz e r to the voltage in the
e le c tric a l sy stem .
3. It can, fo r a lim ited tim e, fu rn ish c u rre n t
when e le c tric a l dem ands of the sy stem exceed
output of the g e n e ra to r.
BATTERY PRECAUTIONS
1. The e le c tric a l c irc u it is N E G A T I V E
G R O U N D . Installing b a tte ry with p o sitiv e te r m ­
inal grounded w ill re s u lt in s e rio u s dam age to the
g e n e ra to r, b a tte ry , and b a tte ry ca b les.
2. When using a b o o ste r b a tte ry o r c h a rg e r,
connect negative b a tte ry o r c h a rg e r te rm in a ls to ­
g eth er and positive b a tte ry o r c h a rg e r te rm in a ls
to gether.
3. DO NOT sm oke n ea r a b attery which is b e­
ing charged.
COMMON CAUSES OF BATTERY FAILURE
When a b a tte ry fa ils, the cause of fa ilu re may
lie outside the b attery itse lf. F o r th is re aso n , when
a b attery fa ilu re is encountered, do not be satisfied
to m erely re c h a rg e o r re p la ce it. Find the cause
of the fa ilu re and p re v en t re c u rre n c e of the troub le.
Listed, below a r e som e of the common ca u ses of
b a tte ry failure:
1. D efect in generating sy stem such a s high
re s is ta n c e , slipping g e n e ra to r d rive belt, faulty
g e n e ra to r o r re g u la to r.
2. O verloads caused by defective s t a r t e r o r
ex cessiv e u se of a c c e s s o rie s .
3. B attery abuse, including fa ilu re to keep
b a tte ry top clean, cable clam ps clean and tight,
and im p ro p er addition of w ater to the c e lls.
4. H ardened b a tte ry p lates, commonly called
"su lfatio n ,” due to b a tte ry being in a low s ta te of
ch arg e o ver a long p erio d of tim e.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL