Schumacher PST-200 User Manual
Page 3
3
If the tester indicates poor battery condition, allow the battery to stabilize for a few
minutes and check the open circuit voltage with voltmeter. This is a good measure
of the percent charge in the battery. The battery is considered charged if it mea-
sures 75% or more. If it failed the load test with 75% charge or above, it should be
replaced. If the battery charge measures less than 75%, it should be charged and
load tested again. Replace the battery if it fails again. The values in the following
chart are for a 12 volt battery:
OPEN CIRCUIT VOLTS*
PERCENT OF CHARGE
11.7 Volts or lower
0
12.0
25
12.2
50
12.4
75
12.6 or higher
100
TESTING THE CHARGING SYSTEM - after battery load test
1. With the tester still connected to the battery, press “START TEST” to toggle the
“TEST STATE” lights from “LOAD” to “CHARGING”.
2. Start the engine and allow it to reach normal operating temperature.
3. Run engine at 1200 to 1500rpm. CAUTION: Stay clear of moving engine parts.
4. Read the results. Illumination of the RED-”BAD” light indicates a problem in the
charging system that will undercharge a battery (less than 13.6V), or overcharge
the battery (over 14.8v)
STARTER MOTOR TEST (12 VOLT VEHICLES ONLY)
This test identifies excessive starter current draw, which makes starting difficult
and shortens battery life. Perform battery load test-first to make sure battery is in
“GOOD” condition.
ENGINE MUST BE AT NORMAL OPERATING TEMPERATURE
1. Connect negative (black) clamp to the negative (NEG, N, -) battery post. Connect
positive (red) clamp to the positive (POS, P, +) battery post. ROCK clamps back
and forth to ensure a good electrical connection. Do not click “START TEST”.
2. Disable the system ignition so the vehicle engine will not start.
3. Crank the engine and note the voltage reading during engine cranking.
4. A meter reading of 9 volts or less indicates excessive current draw. This may be
due to bad connections, a failing starter motor, or the battery is too small for the
vehicle’s requirements.