Generac Power Systems 941-2 - Manual (Page 96)

Section 6.3
ENGINE CRANKING SYSTEM
BATTERY (CONTINUED)
TESTING A BATTERY:
The best method of testing a battery is with an auto-
motive type battery hydrometer. Some "Maintenance
Free" batteries cannot be tested with a hydrometer.
Most batteries can be tested for both STATE OF
CHARGE and CONDITION as follows:
1. Test for State of Charge:
a. Follow the hydrometer manufacturer's instruc-
tions carefully. Test the specific gravity of the
fluid in all battery cells.
b. If the hydrometer does not have a "Percentage
of Charge" scale, compare the readings
obtained with the following:
SPECIFIC GRAVITY PERCENTAGE OF CHARGE
1.260 100%
1.230 75%
1.200 50%
1.170 25%
If the battery State of Charge is less than 100%, use
an automotive type battery charger to recharge it to a
100% State of Charge.
2. Test for Condition:
a. If the difference in specific gravity between the
highest and lowest reading cell is greater than
0.050 (50 points), the battery is nearing the end
of its useful life and should be replaced.
b. However, if the highest reading cell is less than
1.230, recharge the battery and repeat the test.
START-RUN-STOP SWITCH (SW1)
Wires 17 and 18 connect to the two outer terminals of the
switch. Wire 0 (ground) connects to the switch center termi-
nal. The switch can be tested using a volt-ohm-milliamme-
ter (VOM) as follows:
Figure 2.
1. Set the VOM to its "Rx1 " scale and zero the meter.
2. Connect the VOM test leads across the Wire 17 terminal and
the center (Wire 0) terminals.
a. Hold the switch at "START" and the VOM
should indicate "continuity".
b. Hold switch at "STOP" and meter should read
"infinity".
3. Now, connect the meter test leads across the center and Wire
18 terminals.
a. With switch at "START" VOM should indicate
"infinity".
b. With switch at "STOP", meter should read "con-
tinuity".
Replace the switch if it is defective.
STARTER CONTACTOR
WIRE AND CABLE CONNECTIONS:
The red (positive) battery cable connects to one of
the starter contactor's large terminal lugs. The unit's
15 amp fuse also attaches to this lug, via Wire 13.
The starter motor (SM1) cable (16) attaches to the
second terminal lug.
Wire 56, from the A6060 circuit board, attaches to
one of the small contactor terminals.
TESTING THE STARTER CONTACTOR:
To test the installed Starter Contactor, proceed as fol-
lows:
1. Set a volt-ohm-milliammeter (VOM) to read battery voltage (12
VDC).
2. Connect the VOM test leads across the Wire 56 terminal of the
Contactor and frame ground. The meter should indicate "zero"
volts.
3. Hold the Start-Run-Stop switch at "START" and the VOM
should read battery voltage and the Contactor should energize.
After reading the voltage, release the switch. If battery voltage
is NOT indicated, a problem exists elsewhere in the circuit.
4. Connect the VOM test leads across the Wire 16 terminal lug
and frame ground.
a. Hold the Start-Run-Stop switch at "START". The
Contactor should actuate and the meter should
indicate battery voltage.
b. If battery voltage is not indicated, replace the
Starter Contactor.
c. If battery voltage is indicated but engine does
not crank, check the Starter Motor and its cable.
Page 6.3-2