Page 1196 - Workshop Manual - Aumark (BJ1051)

53-20
Battery-Battery

(b). Conversion formula of electrolyte density: d 25 = dt + 0.007 (t － 25)
Items Explanation
d 25 Electrolyte density at 25 ℃
dt Electrolyte density at t℃
0.007 Temperature coefficient
t Measured electrolyte temperature
(c). Measure the temperature of electrolyte at the same time of measuring the specific gravity,
and then convert the measured value into specific gravity at 15 ℃. The specific gravity of
3
electrolyte will decrease 0.007 g / cm when the temperature increases one degree, and in
China we take 15 ℃ as standard. Correct the value according to temperature after
measurement. Add the corrected value if it exceeds 15 ℃, and deduct the corrected value if
it lower than 15 ℃. The corrected value should be accord to the following table.
Measured electrolyte temperature +45 +30 +15 0 -15 -30 -45
Corrected value of hydrometer reading +0.02 +0.01 0 -0.01 -0.02 -0.03 -0.04

3. Selection of specific gravity of electrolyte
Specific gravity of electrolyte increases and the freezing point of electrolyte will decrease,
which will decrease the dangerous of frost and increase the battery capacity. The viscous of
electrolyte will increase if the specific gravity is too big which will make the penetration
difficult; instead the battery capacity will be decreased; this will speed up the carbonization
of wooden separator, and the pole plate will be vulcanize easily; the service life to battery
will be shorten. So select different specific gravity according to different application
conditions. The selection of specific gravity in different areas and different climates can refer
to the following table.
Electrolyte specific gravity at 15℃ for a fully charged
Climates battery
Winter Summer

Area with temperature lower 1.31 1.27
than -40 ℃ in winter
Area with temperature above
-40 ℃ in winter 1.29 1.25
Area with temperature above
1.28 1.25
-30 ℃ in winter
Area with temperature above
1.27 1.24
-20 ℃ in winter
Area with temperature above 0
℃ in winter 1.24 1.24

Page 1196