Harbor Freight Tools 91129 User's Manual

500 AMP
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit our Web site at http://www.harborfreight.com
Copyright © 2004 by Harbor Freight Tools®. All rights reserved. No portion of this manual
or any artwork contained herein may be reproduced in any shape or form without the express
written consent of Harbor Freight Tools.
For technical questions and replacement parts, please call 1-800-444-3353
Testing Capability
Load Test Capacity
Display Meters
Test Cycle
Battery Cable / Clamps
Overall Dimensions
12 VDC batteries, alternators, starters
160 amp hour; Up to 1000 cold cranking
amps maximum testing; 0 ~ 500A load
Analog, 0~16 VDC (maximum)
Analog, 0~500A; 0~160AH; 0~1000 CCA
15 seconds per test with 1 minute cool
down; 3 tests in 5 minutes
3 (L) feet, copper plated clamps, # 4 AWG
10-1/2 (W) x 9 (H) x 5 (D) inches
8.7 lbs.
Carrying handle and four rubber feet
Save This Manual
You will need the manual for the safety warnings and precautions, assembly instructions,
operating and maintenance procedures, parts list and diagram. Keep your invoice with this
manual. Write the invoice number on the inside of the front cover. Keep the manual and
invoice in a safe and dry place for future reference.
General Safety Warnings and Precautions
WARNING: When using tool, basic safety precautions should always be followed to reduce the risk of personal injury and damage to equipment.
Read all instructions before using this tool!
Keep work area clean. Cluttered areas invite injuries.
Observe work area conditions. Do not use machines or power tools in damp or wet
locations. Don’t expose to rain. Keep work area well lit. Do not use electrically
powered tools in the presence of flammable gases or liquids.
Keep children away. Children must never be allowed in the work area. Do not let
them handle machines, tools, or extension cords.
Store idle equipment. When not in use, tools must be stored in a dry location to
inhibit rust. Always lock up tools and keep out of reach of children.
Use the right tool for the job. Do not attempt to force a small tool or attachment to do
the work of a larger industrial tool. There are certain applications for which this tool
was designed. It will do the job better and more safely at the rate for which it was
intended. Do not modify this tool and do not use this tool for a purpose for which it was
not intended.
Dress properly. Do not wear loose clothing or jewelry as they can be caught in
moving parts. Protective, electrically non-conductive clothes and non-skid footwear
are recommended when working. Wear restrictive hair covering to contain long hair.
SKU 91129
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Page 2
Use eye and ear protection. Always wear ANSI approved impact safety goggles.
Wear an ANSI approved dust mask or respirator when working around metal, wood,
and chemical dusts and mists.
Do not overreach. Keep proper footing and balance at all times. Do not reach over or
across running machines.
Maintain tools with care. Inspect tool cords periodically and, if damaged, have them
repaired by a qualified technician. The handles must be kept clean, dry, and free from
oil and grease at all times.
Disconnect power. Disconnect Load Tester from battery when not in use.
Stay alert. Watch what you are doing, use common sense. Do not operate any tool
when you are tired.
Check for damaged parts. Before using any tool, any part that appears damaged
should be carefully checked to determine that it will operate properly and perform its
intended function. Check for any broken parts and any other condition that may affect
proper operation. Any part that is damaged should be properly repaired or replaced by
a qualified technician. Do not use the tool if any switch does not turn On and Off
Guard against short circuits. Never make contact between battery terminals with
anything metal during load testing.
Replacement parts and accessories. When servicing, use only identical
replacement parts. Use of any other parts will void the warranty. Only use accessories
intended for use with this tool. Approved accessories are available from Harbor Freight
Do not operate tool if under the influence of alcohol or drugs. Read warning
labels if taking prescription medicine to determine if your judgment or reflexes are
impaired while taking drugs. If there is any doubt, do not operate the tool.
Maintenance. For your safety, service and maintenance should be performed
regularly by a qualified technician.
People with pacemakers should consult their physician(s) before using this
product. Electromagnetic fields, caused by running engines, in close proximity to a
heart pacemaker could cause interference to or failure of the pacemaker.
In addition, people with pacemakers should adhere to the following:
Caution is necessary when near the coil, spark plug cables, or distributor of a
running engine. The engine should always be off if adjustments are to be made
to the distributor.
Specific Safety Precautions for the Load Tester
When connecting the Battery Cables to the battery, avoid creating sparks; especially
when the battery is being charged. Explosive gases are created during charging.
Sparking could also damage the vehicle electrical system.
SKU 91129
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Page 3
Do not touch the cooling vents on the Load Tester during or immediately after
testing the battery. They become very hot.
When placing the Load Tester in the vehicle’s engine compartment, take special
care that the metal housing of the Tester does not come in contact with either
terminal of the battery or other electrical connections.
Be certain of the test battery polarity before connecting the test Cable Clamps. The red
Cable Clamp goes to the positive terminal of the battery. The black Cable Clamp goes
to the negative terminal of the battery. Reversing Load Tester Cable Clamps on the
battery will damage the tester.
Do not drop the Load Tester as it may affect proper operation.
Do not smoke or have open flames near the battery.
Do not connect the Load Tester to the battery while the engine is running. Turn the
engine off before connecting.
Warning: The warnings, cautions, and instructions discussed in this instruction manual
cannot cover all possible conditions and situations that may occur. It must be understood by the operator that common sense and caution are factors which cannot be
built into this product, but must be supplied by the operator.
When unpacking, check to make sure that all the parts are included. Refer to the Assembly
section, and the Assembly Drawing and Parts List at the end of this manual. If any parts are
missing or broken, please call Harbor Freight Tools at the number on the cover of this
manual as soon as possible.
(B) Black Cable: Clamp to
Battery Negative (-) Terminal
(A) Red Cable: Clamp to
Battery Positive (+) Terminal
SKU 91129
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Page 4
Testing the Battery
Wipe the battery terminals with a cloth to remove any dirt and grease.
Make sure the Load Knob (C) is in the off position. Connect the red (positive) Cable
Clamp (A) to the positive terminal (+) on the 12 V battery. See photo on page 4.
Connect the black (negative) Cable Clamp (B) to the negative terminal (–) on the
Turn the Load Knob (C) clockwise until the DC ammeter reads 1/2 the Cold Crank
Amp (CCA) rating or three times the amphour (AH) capacity of the battery. The CCA
and AH rating are printed on the battery label.
Maintain load for 15 seconds to simulate an actual load on the battery. After 15
seconds has passed, the unit will sound with a beep.
View the DC Volts Meter and read the battery condition. Refer to the “Battery Condition
Analysis” section on the next page.
Turn the Load Knob (C) counterclockwise to Off, and remove the Cable Clamps from
the battery.
Note: Freezing temperatures affect the battery test reading. Decrease the battery rating
50 cold cranking amps for each 50°F (10°C) below freezing 30°F (0°C).
Battery Test: Green
- OK
Red - Replace
Amps Scale
Amp Hour Scale
State of Charge:
Green - OK
Red - Recharge
CCA Scale
Alternator &
Regulator Test:
Green - OK
Red - Low
Load Knob (C)
Cable (-)
SKU 91129
Cable (+)
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Page 5
Testing the Charging System
Turn the Load Knob (C) counterclockwise to the Off position.
Connect the Cable Clamps to the battery as previously described.
Avoid Carbon Monoxide poisoning. This gas comes
from the vehicle’s exhaust and is colorless and odorless.
It can cause SERIOUS INJURY or DEATH if inhaled.
Outside, or in a well ventilated area, start the vehicle engine and run at fast idle speed.
View the DC Volt Meter and read the Alt. - Reg. condition. Refer to the “Battery
Condition Analysis” section below.
Turn the vehicle’s engine off, then remove the Load Tester Cable Clamps.
Battery Condition Analysis
LOAD TEST / 15 Sec.
(Display Reading)
(Green area)
(Red area)
(Alt. & Reg. Test)
SKU 91129
Battery capacity is good. May or may not be fully charged. Check the
charge state by testing the Specific Gravity (SG) with a Hydrometer.
If SG is less than full charge, check for possible charging system
trouble. Recharge to full level.
If the DC Volt Meter needle is falling, the battery is defective or has a
bad cell. For a quick check, turn the Load Knob down,
counterclockwise and note DC Volt Meter reaction. If voltage
recovers to its full potential after only a few seconds, the battery is
probably defective. If the voltage recovers slowly, the battery may
only be run down. Check specific gravity level, recharge, and re-test.
If the DC Volt Meter needle reads OK, charging system is functional.
If it falls on the low red or high red areas, charging system may be
For technical questions, please call 1-800-444-3353.
Page 6
Starter Motor Test
If starting your vehicle is difficult, you may have unnecessary starter motor draw, which
dramatically shortens battery life. This test identifies starter motor performance.
Make sure your engine is running at normal operating temperature, and that the battery
is fully charged and in good condition.
Connect the Red Clamp (+) to the positive (+) terminal post on the battery. Connect the
Black Clamp (-) to the negative (-) terminal post on the battery.
Turn the Load Knob (C) counterclockwise to the Off position.
Disable the engine to make sure the car will not start. Refer to your vehicle’s service /
technical manual.
While watching the DC Volt scale (see page 6), crank the engine briefly to determine
the voltage reading during cranking.
A display reading of 9 volts or less indicates excessive current draw. This may be
caused by a bad connection of a failing starter motor, or, the battery is too small for the
vehicle’s requirements. Consult a qualified mechanic.
When starter motor test is complete, remove Black Clamp (-) from battery first; then
remove Red (+) clamp.
Periodically check all nuts, bolts, and screws for tightness.
Store in a clean, dry location.
Clean the outside of the unit with a damp cloth. Never use solvents to clean any parts
of this tool. Use compressed air to blow out debris from the load vents. Allow tool to
dry completely before use.
After each use, clean the Cable Clamps of any possible battery electrolyte. Apply a
thin coat of silicon grease to prevent corrosion.
Replaceable Parts
The Carbon Pile Load Tester has no replaceable parts.
REV 04/05
SKU 91129
For technical questions, please call 1-800-444-3353.
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