Schumacher Electric BT453 Owner's Manual page 4

TABLE 1 – METER REACTION AFTER 10 SECONDS OF LOAD
LOAD TEST
GOOD (GREEN BAND)
after 10 seconds of load.
WEAK OR BAD, BUT STEADY (meter
reading steady after 10 seconds of load).
WEAK OR BAD AND FALLING (meter
continues to fall after 10 seconds of load).
TEMPERATURE COMPENSATION
BATTERY TEMPERATURE
DECREASE BATTERY RATING BY:
(1 STEP = 50 cranking amps.)
If the load indicates poor battery condition, allow the battery to stabilize for a few minutes and check the open circuit voltage by voltmeter. This is a good measure of the
percent charge in the battery. The battery is considered charged if it measures 75% or more. If it failed the load test with 75% charge, 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 charge are for a 12 volt
battery; divide these in half for 6 volt batteries.
OPEN CIRCUIT VOLTS
11.7 Volts or lower
12.0
12.2
12.4
12.6 or higher
4. TESTING THE CHARGING SYSTEM
1. Connect the tester the same as for battery testing.
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. Do not press the load switch.
4. Read the meter. A reading in the red band area indicates a problem in the charging system that will undercharge a battery; if the meter is beyond the OK area, the
charging system is likely to overcharge the battery.
5. METER
2
1
BATTERY
LOAD TEST
BATTERY CONDITION
Battery capacity is good. May or may not be fully charged. Determine state of charge by checking specific gravity
(use hydrometer). If gravity is less than full charge, check for possible charging system trouble or electrical drain.
Recharge battery to full charge.
Battery capacity is unsatisfactory. Battery may be either: (1) defective or (2) partly discharged. To determine which, check
specific gravity. If gravity is over 1.225, battery is considered defective. If gravity is under 1.225, recharge battery and
retest. If cell-to-cell gravity varies more than 0.025 (25 points), cell trouble may exist. If charging does not bring gravity to
full charge level, the battery is either sulfated or has lost active material.
Battery may be defective (e.g. a bad cell). For a quick check, release load switch and note volt meter reaction. If voltage
recovers to 12.0 volts or more in a few seconds battery is probably defective. If voltage recovers slowly, battery may be
only very run down. For more accurate results, check gravity and follow above procedure.
+20˚F
0˚F
1 STEP
2 STEPS
PERCENT OF CHARGE
0
25
50
75
100
3
VOLTS
4
CCA
CHARGING
SYSTEM
-20˚F
3 STEPS
1. Voltage scale
2. Range for 6 volt battery load testing
3. Range for 12 volt battery load testing
4. Charging system test range
5. Cold cranking amps range
5
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