Yanmar 4LHA-HTP Operation Manual page 629

Chapter 9 Electrical System
2. Battery
2-3.2 Checking the electrolyte
(1) Electrolyte level
Low
Good
Check the electrolyte level every 7 to 10 days. The
electrolyte must always be 10 ~ 20mm (0.3937 ~
0.7874in.) over the top of the plates.
NOTES: 1. The "LEVEL" line on a transparent plastic bat-
tery case indicates the height of the elec-
trolyte.
2. Always use distilled water to bring up the elec-
trolyte level.
3. When the electrolyte has leaked out, add dilute
sulfuric acid with the same specific gravity as
the electrolyte.
(2) Measuring the specific gravity of the electrolyte
1) Draw some of the electrolyte up into a hy-
drometer.
2) Take the specific gravity reading at the top of the
scale of the hydrometer.
Rubber bulb..
Glass tube
Float
3) The battery is fully charged if the specific gravity
is 1.260 at an electrolyte temperature of 20
battery is discharged if the specific gravity is 1.200
High
Hydrometer
- Read top of scale
C. The
o
9-4
(50%). If the specific gravity is below 1.200,
recharge the battery.
4) If the difference in the specific gravity among the
cells of the battery is ±0.01, the battery is OK.
5) Measure the temperature of the electrolyte.
Since the specific gravity changes with the
temperature, 20 C is used as the reference
o
temperature.
Reading the specific gravity at 2 0
S,» = St + 0.0007 (t-20)
S»: Specific gravity at the standard temperature of
2 0 C
o
St: Specific gravity of the electrolyte at t
0.0007: Specific gravity change per 1
t: Temperature of electrolyte
2-3.3 Voltage test
Using a battery tester, the amount of discharge can be
determined by measuring the voltage drop which occurs
while the battery is being discharged with a large current.
Battery tester
(1) Connect the tester to the battery.
12V battery tester
Adjust the current (A).
(2) Connect the (+) lead of the tester to the (+) battery
terminal, and the (-) tester lead to the (-) battery
terminal.
(3) Push the TEST button, wait 5 seconds, and then read
the meter.
• Repeat the test twice to make sure that the meter
indication remains the same.
2-3.4 Washing the battery
(1) Wash the outside of the battery with a brush while
running cold or warm water over the battery. (Make
sure that no water gets into the battery.)
(2) When the terminals or other metal parts are corroded
due to exposure to electrolyte leakage, wash off all the
acid.
(3) Check the vent holes of the caps and clean if clogged.
(4) After washing the battery, dry it with compressed air,
connect the battery cable, and coat the terminals with
grease. Since the grease acts as an insulator, do not
coat the terminals before connecting the cables.
, 4LHA Series
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