Hydrometer - Cushman AC TUG Owner's Manual

M
AINTENANCE
AC Voltage
Battery charger output is directly related to the input voltage. If multiple vehicles are receiving an incomplete charge in
a normally adequate time period, low AC voltage could be the cause and the power company should be consulted.
Troubleshooting
In general, troubleshooting will be done for two distinct reasons. First, a battery that performs poorly and is outside of
the manufacturers specification should be identified in order to replace it under the terms of the manufacturer's war-
ranty. Different manufacturers have different requirements. Consult the battery manufacturer or the manufacturer's
representative for specific requirements.
The second reason is to determine why a particular vehicle does not perform adequately. Performance problems may
result in a vehicle that runs slowly or in a vehicle that is unable to operate for the time required.
A new battery must mature before it will develop its maximum capacity. Maturing may take up to 100 charge/dis-
charge cycles. After the maturing phase, the older a battery gets, the lower the capacity. The only way to determine
the capacity of a battery is to perform a load test using a discharge machine following manufacturer's recommenda-
tions.
A cost effective way to identify a poorly performing battery is to use a hydrometer to identify a battery in a set with a
lower than normal specific gravity. Once the particular cell or cells that are the problem are identified, the suspect bat-
tery can be removed and replaced. At this point there is nothing that can be done to salvage the battery; however, the
individual battery should be replaced with a good battery of the same brand, type and approximate age.

HYDROMETER

A hydrometer (P/N 50900-G1) is used to
test the state of charge of a battery cell. This
is performed by measuring the density of
the electrolyte, which is accomplished by
measuring the specific gravity of the electro-
lyte. The greater the concentration of sulfu-
ric acid, the more dense the electrolyte
becomes. The higher the density, the higher
the state of charge.
To prevent battery explosion that could
result in severe personal injury or death,
never insert a metal thermometer into a
battery. Use a hydrometer with a built in
thermometer that is designed for testing
batteries.
Specific gravity is the measurement of a liq-
uid that is compared to a baseline. The
baseline is water which is assigned a base
number of 1.000. The concentration of sulfu-
ric acid to water in a new battery is 1.280
which means that the electrolyte weighs
1.280 times the weight of the same volume
of water. A fully charged battery will test at
1.275 - 1.280 while a discharged battery will
read in the 1.140 range.
NOTICE: Do not perform a hydrometer test on a battery that has just been watered. The battery must go
through at least one charge and discharge cycle in order to permit the water to adequately mix with
the electrolyte.
The temperature of the electrolyte is important since the hydrometer reading must be corrected to 80° F (27° C). High
quality hydrometers are equipped with an internal thermometer that will measure the temperature of the electrolyte
and will include a conversion scale to correct the float reading. It is important to recognize that the electrolyte tempera-
ture is significantly different from the ambient temperature if the vehicle has been operated.
36
Cylinder
Thermometer
Add to Float
Reading
Subtract
from Float
Reading
Bulb Float
Hydrometer
Weight