Schumacher PST-1000 User Manual
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readings are taken, the battery should be charged five minutes
to stimulate mixing. (Refer to battery manufacturer ’s
instructions regarding removal of vent caps while charging
battery).
ELECTROLYTE CAUTION
Battery electrolyte is SULFURIC ACID. It can eat holes in
clothes and skin. Flush spills with water.
STATE OF CHARGE CHECK
By Specific Gravity (open vent battery only)
Sample, measure and return the electrolyte from each cell with a
hydrometer.
1.
The specific gravity should be at least 1.230 in all cells. If
not, charge the battery. If charging the battery does not bring
the specific gravity up to 1.230, then the battery should be
replaced.
2.
The specific gravity readings should not vary more than 50
points (.050) between all cells. If the difference is greater,
replace the battery.
By Open Circuit Voltage (any lead-acid battery)
Measure the open circuit (no load) stabilized voltage. A stabilized
battery has no “surface charge”, which means that the electro-
lyte has had a chance to remix and shed gas bubbles after cur-
rent flow has stopped.
Open Circuit Volts
12.6
12.4
12.2
12.0
% of Charge
100
75
50
25
If the measured voltage is less than 12.4 volts, first recharge the
battery. With a low % of charge, performance will be reduced
and any load test results may be invalid.
LOAD TEST
A battery must have the capability to crank an engine while main-
taining enough voltage to power the ignition. To give consistent
results, these tests require that a battery be at least 75% charged
and must not have been heavily used within the last 10 minutes.
The standard battery performance test is based on battery rat-
ings provided by the manufacturer. If the test load amperage is
known, use it, otherwise use one of the following:
1.
Cold Cranking Amperes at 0°F. (CCA) - When using CCA,
divide the given value by 2 to obtain the load. FOR example,
1000 CCA divided by 2 equals a 500 amperes test load.
2.
Ampere Hour Rating (Ah) - If only the Ampere Hour rating is
known, multiply the value by 3 to obtain the load. For example,
a 200 Ah battery times 3 equals a 600 amperes load.
3.
BATTERY WATTS - When only the battery rating in watts is
known then use Table 1 (below) as a guide to determine
what battery load or cranking amps would be normal. FOR
EXAMPLE: A battery load or cranking amps for a battery
rated at 2400 watts would be 125 to 200 amps.
TABLE 1
Battery Load or
Engine
Cubic
Cubic
Cranking Amp
Watt
Size
Inches
Centimeters
Rating
Small
100 to 200
1600 to 2400
100-150 Amps 1200 to 1800
Medium
200 to 350
2400 to 5600
125-200 Amps 1500 to 2400
Large
350 to 500
5600 to 8000
175-300 Amps 2100 to 3600
Ratings can be found on the battery, in the vehicle manual or in a
replacement battery application guide. In the battery performance
load test, the rated amperage is drawn from the battery for 15
seconds while watching the battery voltage. At 70°F and higher,
a good battery will maintain an output of 9.6 volts or more during
the load testing period (4.8 volts for 6 volt battery). When a bat-
tery is cooler than 70°F, the output voltage requirement is re-
duced to give equivalent test conclusions per the following
(Table 2):
Table 2
ELECTROLYTE TEMP
MINIMUM
–°F–
–°C–
LOADED VOLTS
70
21
9.6
60
16
9.5
50
10
9.4
40
4
9.3
30
-1
9.1
20
-7
8.9
10
-12
.7
0
-18
8.5
NOTE: DIVIDE MINIMUM TEST VOLTAGE IN HALF FOR 6 VOLT
BATTERIES.
LOAD TEST CAUTION
If the amperes display goes out while loading a battery, the
voltage has fallen below 4.0 volts. TURN THE LOAD OFF IM-
MEDIATELY.
The battery could become overheated. If a battery smokes
while being loaded, immediately discontinue using it. It is
not safe.
BLACK
RED
BATTERY
CHASSIS
Zero Amp Meter. Then Place AMP PROBE around either ana-
lyzer cable.
Figure 1
Connection for LOAD TEST
1.
Have the Load knob turned to “OFF” before connecting.
2.
Connect analyzer Battery Clamps to battery terminals, Red
to POS (+), Black to NEG (-) the cables can be reverse.
Wiggle clamps to be sure that the clamp jaws make good
contact with battery terminals.
3.
Set the Volts Selector to “Battery Volts”. The analyzer should
show battery voltage over 12.4V. (6.2V)