- Yuasa Battery, Inc. Automobile Battery Charger User Manual

Battery Testing
Methods of Checking Battery Condition
State of Syringe Digital 5-Ball
Charge Hydrometer Voltmeter Hydrometer
100% Charged
w/Sulfate Stop 1.280 12.80v 5 Balls Floating
100% Charged 1.265 12.60v 4 Balls Floating
75% Charged 1.210 12.40v 3 Balls Floating
50% Charged 1.160 12.10v 2 Balls Floating
25% Charged 1.120 11.90v 1 Balls Floating
0% Charged less than 1.100 less than 11.80v 0 Balls Floating
POINTS TO REMEMBER
❐ Use a voltmeter or hydrometer to test state of charge.
❐ In extreme cold or heat, you’ll have to adjust hydrometer readings.
❐ Battery can be tested with or without electrical load applied.
❐ Unloaded testing is simplest.
❐ Applying a load and reading voltage at battery is more accurate.
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A battery’s specific gravity changes with temperature.
Ideally, readings should be taken at 77°F. Is it really
going to matter if you’re off a couple of degrees one way
or another? Probably not. If you’re working somewhere
that’s uncomfortably hot or cold, it’s time to use the old
conversion factors: add .001 to the specific gravity read-
ing for each 3°F above 77°F or subtract .001 from the
specific gravity reading for each 3°F below 77°F. Cell
voltage can be found by adding .84 to the specific gravity.
Note, too, that YUASA’s “Sulfate Stop,” a chemical addi-
tive that increases battery life by drastically reducing sul-
fate buildup, changes the specific gravity readings; they’ll
be higher than with ordinary batteries.
Test sealed VRLA types with a voltmeter or
multimeter. If the stabilized open circuit voltage is
below 12.5v, the battery needs charging. For a stabilized
open circuit reading, first allow the battery to remain in
an open circuit condition for at least 1 - 2 hours.
LOADED TESTING: There are two types of loaded tests
for motorcycle batteries. You’ll need a voltmeter or multi-
meter.
Low-load test: Basically, this means turning on the
bike’s lights and taking a voltage reading at the battery.
Remember, hook positive (+) to positive (+), negative (-) to
negative (-). The battery in a 12v system should have at
least 11.5v DC with the lights on. A 6v system should
have at least 5.75v DC. If voltage drops below these lev-
els, it’s time to charge.
High-rate discharge test: This is the best test of bat-
tery condition under a starting load. Use a load testing
device that has an adjustable load. Apply a load of three
times the ampere-hour rating.
At 14 seconds into the test, check battery voltage: a
good 12v battery will have at least 10.5v, and a good 6v
battery, at least 5.25v. If the reading’s low, charge.
There are two types of battery tests: unloaded and
loaded. An unloaded test is made on a battery without
discharging current. It’s simplest and most commonly
used. If you need a precise reading, loaded testing is the
answer. It’s more accurate.
UNLOADED TESTING: Check charge condition using
either a hydrometer or voltmeter. With a voltmeter,
voltage readings appear instantly to show the state of
charge. Remember to hook the positive lead to the
battery’s positive terminal, and the negative lead to the
negative terminal.
A hydrometer measures the specific gravity of each cell.
The specific gravity tells the degree of charge;
generally, a specific gravity of about 1.265 to
1.280 indicates a full charge. A reading of 1.230
to 1.260 indicates the battery should be charged before
testing. The chart below shows the charge level as
measured by syringe float hydrometer, digital voltmeter
and five-ball hydrometer.
3
SECTION
Inspecting, Testing
and Charging