Cen-Tech Battery Charger Item 667 Manual

The Cen-Tech Battery Charger (Item 667) is a versatile charger designed for automotive and marine lead-acid batteries. It features multiple charging modes (standard, deep cycle, AGM), a digital display showing voltage/current/charge percentage, reverse polarity protection, spark-proof technology, and a desulfation mode to help restore old batteries. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Batteries 7. Charging Modes 8. Maintenance Mode 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Digital display, Mode selection buttons, Battery clamps (red/black), AC power cord, Charging status LEDs.

Feature	Description
Digital Display	Shows battery voltage, charging current, and charge percentage
Charging Modes	Standard, Deep Cycle, AGM, and Maintenance modes
Reverse Polarity Protection	Prevents damage if clamps are connected incorrectly
Spark-Proof Technology	Ensures safe connection to battery terminals
Desulfation Mode	Helps recover sulfated batteries
AC Input	Standard 120V AC, 60Hz power input
Battery Clamps	Heavy-duty, insulated clamps for secure connection
Charge Status LEDs	Indicates charging, fully charged, and fault conditions
Float Mode	Maintains battery at optimal charge without overcharging
Overheat Protection	Automatically reduces charge rate if unit overheats

Installation

Unpack and inspect contents. Place charger on stable, dry surface.

Connect to power source: Plug AC cord into grounded 120V outlet.
Prepare battery: Ensure battery is in well-ventilated area. Clean terminals if necessary.
Connect charger: Attach red clamp to positive (+) terminal, black clamp to negative (-) terminal.
Verify connection: Ensure clamps have secure metal-to-metal contact.

WARNING! Keep charger away from water and flammable materials. Do not charge frozen batteries.

First-Time Setup

Power on charger; follow display prompts.

Select battery type: Press MODE button to choose Standard, Deep Cycle, or AGM.
Set charge rate: Use UP/DOWN buttons to select appropriate amperage (2A, 10A, etc.).
Start charging: Press ENTER to begin charge cycle.
Monitor progress: Display shows voltage, current, and estimated time remaining.

CAUTION! Always connect clamps to battery before plugging into AC outlet. Disconnect in reverse order.

Specifications

Input Voltage: 120V AC, 60Hz.
Output Voltage: 12V DC.
Charge Rates: 2A, 10A, 25A (selectable).
Battery Types: Standard flooded, Deep Cycle, AGM (Absorbent Glass Mat).
Display: Backlit LCD digital display.
Protection Features: Reverse polarity, short circuit, overheat, spark-proof.
Dimensions: 8.5" x 6" x 3.5".
Weight: 4.2 lbs.
Operating Temperature: 32°F to 104°F (0°C to 40°C).

Controls and Settings

Access functions via front panel buttons. Display shows real-time charging data.

Controls: POWER, MODE (select battery type), UP/DOWN (adjust charge rate), ENTER (start/stop), RESET (clear faults).

Settings: Battery type (Standard/Deep Cycle/AGM), Charge rate (2A/10A/25A), Desulfation mode (activate for sulfated batteries), Maintenance mode (float charging). Display shows: Battery voltage, Charging current, Charge percentage, Estimated time remaining, Error codes.

Connecting Batteries

For 12V lead-acid batteries only. Do not use for 6V or 24V systems.

Turn off charger and unplug from AC outlet.
Connect red clamp to positive (+) battery terminal.
Connect black clamp to negative (-) battery terminal or vehicle chassis ground.
Plug charger into AC outlet.
Select settings and start charging.

Tip: For maintenance charging, use 2A setting. For faster charging, use 10A or 25A for appropriate battery sizes.

Charging Modes

Supports multiple battery types and conditions.

Standard Mode: For regular automotive batteries. Provides bulk, absorption, and float stages.
Deep Cycle Mode: For marine/RV batteries with thicker plates. Longer absorption time.
AGM Mode: For Absorbent Glass Mat batteries. Controlled voltage to prevent damage.
Desulfation Mode: Pulses to break down sulfate crystals on battery plates.
Maintenance Mode: Keeps battery at full charge without overcharging (float mode).

WARNING! Do not use AGM mode for flooded batteries. Select correct mode for battery type.

Maintenance Mode

Float charging maintains battery at optimal voltage. Automatically switches to float mode when battery reaches full charge. LED indicates maintenance mode active. Can be left connected indefinitely for seasonal storage.

Care & Cleaning

Unplug and disconnect from battery before cleaning. Wipe exterior with dry cloth. Keep ventilation openings clear of dust. Store in dry location.

CAUTION! Do not use liquids or solvents. Do not immerse in water. Check cables regularly for damage.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits. UL listed. Copyright © 2025 Cen-Tech; trademarks of Harbor Freight Tools. For support, visit www.harborfreight.com or contact 1-800-444-3353.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Charger won't turn on	No AC power/faulty outlet	Check outlet with another device; ensure plug is fully inserted.
Display shows "ERR"	Reverse polarity/loose connection	Check clamp connections; ensure correct polarity.
Battery not charging	Dead battery/wrong settings	Test battery voltage; select correct battery type and charge rate.
Charger overheats	High ambient temp/blocked vents	Move to cooler location; ensure ventilation openings are clear.
Slow charging	Low charge rate setting/bad battery	Increase charge rate if appropriate; test battery condition.

Reset: Unplug from AC, disconnect from battery, wait 60 seconds, then reconnect.

Service: 1-800-444-3353; www.harborfreight.com