Nanni N4.40, Workshop Manual

Page: 107 / 175

ENGINE
03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM
1-S37
Battery Specific Gravity
1. Measure the specific gravity of the electrolyte in each cell with a
hydrometer.
2. If the electrolyte temperature is different from the one that the
hydrometer calibrated, correct the specific gravity
measurement. Use the formula below in
(Reference) .
3. If the specific gravity is less than 1.215 (after it is corrected for
temperature), charge or replace the battery.
4. If the specific gravity is different between 2 cells by more than
0.05, replace the battery.
NOTE
• Hold the hydrometer tube vertically but do not remove it
from the electrolyte.
• Do not put too much electrolyte into the tube.
• Let the float move freely and hold the hydrometer at eye
level.
• You must read the hydrometer at the highest electrolyte
level.
(Reference)
• The specific gravity changes with temperature.
To be accurate, the specific gravity
decreases by 0.0007 when temperature increases by 1 °C
(decreases by 0.0004 when temperature increases by 1 °F),
increases by 0.0007 when temperature decreases by 1 °C
(increases by 0.0004 when temperature decreases by 1 °F).
Thus, if you refer to 20 °C (68 °F), correct the specific gravity
reading by the formula below :
–
Specific gravity at 20 °C = Measured value + 0.0007 ×
(electrolyte temperature
− 20 °C)
– Specific gravity at 68 °F = Measured value + 0.0004 ×
(electrolyte temperature
− 68 °F)
At an electrolyte temperature of 20 °C (68 °F)
M00000003GEG0034US1
Specific Gravity State of Charge
1.260 Sp. Gr. 100 % Charged
1.230 Sp. Gr. 75 % Charged
1.200 Sp. Gr. 50 % Charged
1.170 Sp. Gr. 25 % Charged
1.140 Sp. Gr. Very Little Useful Capacity
1.110 Sp. Gr. Discharged
(a) Good
(b) Bad (c) Bad
KiSC issued 06, 2009 A