Ezgo ST 400 48V, Owner'S Manual & Service Manual

Page: 39 / 55

OPERATION AND SERVICE INFORMATION
Page 24
Owner’s Manual and Service Guide
Read all of Manual to become thoroughly familiar with this vehicle. Pay particular attention to all Notes, Cautions and Warnings
Fig. 26 Hydrometer
Using a Hydrometer
1. Draw electrolyte into the hydrometer several times to
permit the thermometer to adjust to the electrolyte
temperature and note the reading. Examine the color
of the electrolyte. A brown or gray coloration indicates
a problem with the battery and is a sign that the bat-
tery is nearing the end of its life.
2. Draw the minimum quantity of electrolyte into the
hydrometer to permit the float to float freely without
contacting the top or bottom of the cylinder.
3. Hold the hydrometer in a vertical position at eye level
and note the reading where the electrolyte meets the
scale on the float.
4. Add or subtract four points (.004) to the reading for
every 10° F (6°C) the electrolyte temperature is
above or below 80° F (27° C). Adjust the reading to
conform with the electrolyte temperature, e.g., if the
reading indicates a specific gravity of 1.250 and the
electrolyte temperature is 90° F (32° C),
add
four
points (.004) to the 1.250 which gives a corrected
reading of 1.254. Similarly if the temperature was
70° F (21° C),
subtract
four points (.004) from the
1.250 to give a corrected reading of 1.246 (Ref Fig.
27 on page 24).
5. Test each cell and note the readings (corrected to
80° F or 27° C). A variation of fifty points between any
two cell readings (example 1.250 - 1.200) indicates a
problem with the low reading cell(s).
As a battery ages the specific gravity of the electrolyte
will decrease at full charge. This is not a reason to
replace the battery, providing all cells are within fifty
points of each other.
Since the hydrometer test is in response to a vehicle
exhibiting a performance problem, the vehicle should be
recharged and the test repeated. If the results indicate a
weak cell, the battery or batteries should be removed
and replaced with a good battery of the same brand, type
and approximate age.
Fig. 27 Hydrometer Temperature Correction
32
28
24
20
16
12
8
4
0
4
8
12
16
20
24
28
32
36
32
28
24
20
16
12
8
4
0
4 4
8
12 12
16 16
20 20
24 24
28 28
32 32
36 36
1100
1125
1150
1200
1225
1250
1275
1300
1100
1125
1150
1200
1225
1250
1275
1300
Add to Float
Reading
Subtract
from Float
Reading
Bulb
Cylinder
Float
Weight
Thermometer
1175
Ref Hyd 1
160 71.1 +.032
+.030
150 65.6 +.028
+.026
140 60.0 +.024
+.022
130 54.4 +.020
+.018
120 48,9 +.016
+.014
110 43.3 +.012
+.010
100 37.8 +.008
+.006
90 32.2 +.004
+.002
80 26.7 0
–.002
70 21.1 –.004
–.006
60 15.6 –.008
–.010
50 10 –.012
–.014
40 4.4 –.016
–.018
30 –1.1 –.020
–.022
20 –6.7 –.024
–.026
10 –12.12 –.028
EXAMPLE #1:
Electrolyte Temperature
Above 80
°
F (27
°
C)
Electrolyte temperature
90 ° F (32 ° C)
Hydrometer reading 1.250
1.250 + .004 = 1.254
corrected specific gravity
EXAMPLE #2:
Electrolyte Temperature
Below 80
°
F (27
°
C)
Electrolyte temperature
70 ° F (21 ° C)
Hydrometer reading 1.250
1.250 - .004 = 1.246
corrected specific gravity
°
F
°
C
Electrolyte
Temperature