Testing The Charging System - Alternator / Regulator Output - CEN-TECH 92903 Assembly And Operating Instructions Manual

Analyzing test results by color display: The Battery Tester will measure battery out-
put/charge in two ways. The three lights above the LED Window (See FIGURE 1) will
indicate a color telling you the general condition of the battery.
Analyzing test results by Voltage Reading: The LED Window will display a number
along with the color.
Green = Greater than 10.7 V - Battery is fully charged
Yellow = Between 9.0 and 10.7 V - Battery is undercharged
Red = Less Than 9.0 V - Battery is uncharged and possibly damaged
4. If the battery is without significant charge, charge it and check it again under load. The
battery should measure 75% of Open-Circuit Voltage. 75% can be considered fully
charged. If the charging rate reaches at least 75%, but fails to reach 75% during the
load test, it needs replacing. Refer to the table below for 12 Volt battery percentages:
Open Circuit Voltage (V): Less than 11.7V
Battery Charge Percentage
5. When test is complete, remove Black Clamp (-) from battery first; then remove Red
Clamp (+).

TESTING THE CHARGING SYSTEM - Alternator / Regulator Output:

Warning: When testing a system in a car/truck, the vehicle must be on a flat, dry surface.
The transmission must be in park and the emergency brake engaged.
1. Connect the Red Clamp (+) to the positive (+) terminal post on the battery. Connect the
Black Clamp (-) to the negative (-) terminal post on the battery.
2. With the engine off, check the Battery Tester LED Window (See FIGURE 1) to deter-
mine effectiveness of charge. Without using the Test Start Button, If the Battery Tester
does not register and no display is seen, double check that the Clamps are connected
to the proper terminal posts. Make certain a clean connection has been made between
the Clamps and terminal posts.
3. Start the engine and let it run. Without using the Test Start Button, observe the volt-
age readout when the engine speed reaches between 1200 to 1500 RPM (normal idle
speed).
4. Determine battery charge based on color indicators and voltage as described above. If
the battery registers below 75 percent or the readout is not constant, you may have an
alternator/regulator problem. See a qualified service technician.
5. When charging system test is complete, remove Black Clamp (-) from battery first; then
remove Red Clamp (+).
SKU 92903 For technical questions, please call 1-800-444-3353
Operation (continued)
Red = Bad, No Charge, or Completely Discharged
Yellow = Weak, Needs Recharging
Green = Good or Normal - Has Existing Charge
0%
12V 12.2V 12.4V
20% 50%
12.4V+
75% 100%
REV 04/05
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