GILLIG LOW FLOOR, Руководство по обслуживанию

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Electrical System
349
hydrometer test—state of charge
The hydrometer test is merely a means of determining the state of charge of a battery. This test will not
necessarily indicate whether the battery is able to do its job. The following procedures should be fol-
lowed when performing the hydrometer test:
1. See WARNING and hydrometer guidelines on the previous page.
2. Measure the specific gravity of electrolyte in each battery cell. Hold the hydrometer at eye level
so that the float is vertical and free of the outer tube. Draw in just enough liquid from the battery
cell so that the float is freely suspended in the electrolyte. If water has been recently added to the
cells, or if the battery has been fast charged (see “Charging the Battery”), the hydrometer reading
will be inaccurate.
3. Adjust the hydrometer reading according to the temperature of the electrolyte. When the electro-
lyte temperature is above 80° F (27° C), add 4 points (0.004) to the reading for each 10° above
80° F. If electrolyte temperature is below 80° F, subtract four points for each 10° below 80° F.
4. If the specific gravity readings are 1.225–1.270 at 80° F, and variations between cells are less
than 25 gravity points (0.025), the battery presumably is at least 3/4 charged and in good condi -
tion for further use.
5. When charging a sulfated battery, charge at a very low rate—not more than one half the normal
charging rate. Badly sulfated batteries may require up to 100 hours of charging time before they
become fully charged. A continuous slow charge of 48 hours or more may be required before a
rise in specific gravity readings occurs. If the specific gravity reading on any cell fails to reach
1.250 (corrected to 80° F), or if there is a variation of more than 25 gravity points between cells
after a thorough slow charge, replace the battery.