Introduction
This manual provides essential instructions for the safe and effective use of your Schauer JAC1212-R 12V 12A Fully Automatic Battery Charger and Maintainer. Please read this manual thoroughly before operating the device and retain it for future reference.
The Schauer JAC1212-R is an intelligent, fully automatic 3-stage battery charger designed to charge and maintain various lead-acid battery types, including conventional, maintenance-free, deep cycle, gelled-type, AGM, and valve-regulated batteries. Its advanced design ensures optimal charging by following the battery impedance to the end of the charge cycle.
Setup Instructions
- Unpacking: Carefully remove the charger from its packaging. Inspect the unit for any signs of damage. Do not use if damaged.
- Placement: Place the charger in a well-ventilated area, away from direct sunlight, heat sources, and moisture. The aluminum case is designed for durability, and flanges with holes allow for ease of on-board mounting if desired.
- Battery Connection:
- Ensure the charger is unplugged from the AC power outlet before making any connections.
- Connect the positive (+) ring terminal (red) from the charger's DC cordset to the positive (+) terminal of the battery.
- Connect the negative (-) ring terminal (black) from the charger's DC cordset to the negative (-) terminal of the battery.
- Ensure connections are secure and free from corrosion. The DC cordset is 3 feet long with 5/16" ring terminals.
- AC Power Connection: Once the battery is securely connected, plug the charger's AC power cord into a standard 120VAC, 50/60 Hz electrical outlet.

Image: Schauer JAC1212-R 12V 12A Automatic Battery Charger. This image displays the compact design of the charger, featuring its aluminum casing and the attached DC cordset with 5/16" ring terminals for direct battery connection.
Operating Instructions
The Schauer JAC1212-R is a fully automatic 3-stage charger. Once connected to the battery and AC power, it will automatically begin the charging process.
- Power On: A red LED indicator will illuminate, signifying that the charger is receiving AC power.
- Charging Phase: A yellow LED indicator will illuminate when the battery is actively charging. The charger employs a modified constant current charge to a constant finishing voltage.
- Float Mode (Maintenance): Once the battery reaches its full charge, the green LED indicator will illuminate, indicating that the charger has entered float mode. In this stage, the charger maintains the battery at an optimal voltage (2.28 volts per cell float) and can be left connected indefinitely without overcharging. The finishing voltage is 2.4 volts per cell.
- Safety Features: The charger is short-circuit proof and includes reverse polarity protection, enhancing safety during operation.
Important: This unit is not intended for use as a DC power supply.
Maintenance
- Cleaning: Disconnect the charger from both AC power and the battery before cleaning. Wipe the exterior with a dry, soft cloth. Do not use liquid cleaners or solvents.
- Connections: Periodically inspect the battery terminals and charger connections for corrosion or damage. Clean as necessary.
- Storage: When not in use, store the charger in a cool, dry place.
- Ventilation: Ensure the charger's ventilation openings remain clear and unobstructed during operation to prevent overheating.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No LEDs illuminate when plugged in. | No AC power; faulty outlet; charger malfunction. | Check AC outlet with another device. Ensure charger is securely plugged in. If problem persists, contact support. |
| Red LED on, but yellow (charging) LED does not illuminate. | Battery not connected correctly; battery voltage too low; battery is fully charged. | Verify battery connections (positive to positive, negative to negative). Check battery voltage. If battery is fully charged, green LED should be on. |
| Charger gets excessively hot. | Poor ventilation; prolonged heavy load. | Ensure charger is in a well-ventilated area. Clear any obstructions from vents. If overheating persists, disconnect and contact support. |
| Green LED (float mode) does not illuminate after extended charging. | Battery severely discharged or damaged; charger malfunction. | Allow more time for charging. Test battery condition. If battery is healthy and charging is prolonged, contact support. |
Specifications
- Model: JAC1212-R
- Input Voltage: 120VAC, 50/60 Hz
- Output Voltage: 12 Volts (DC)
- Current Rating: 12 Amps
- Charge Control: Modified constant current to constant finishing voltage, then to float standby
- Finishing Voltage: 2.4 volts per cell
- Float Voltage: 2.28 volts per cell
- Duty Cycle: 100% continuous at full load (2.1 volts per cell)
- DC Cordset: 3 ft long with 5/16" ring terminals
- Safety Features: Short circuit proof, reverse polarity protection, current limiting
- Case Material: Aluminum
- Compliance: UL Listed
- Compatible Battery Types: Conventional, maintenance-free, deep cycle, gelled-type, AGM, valve-regulated lead-acid batteries.
Warranty Information
Specific warranty details are typically provided with the product packaging or on the manufacturer's official website. Please refer to those resources for the most accurate and up-to-date warranty terms and conditions for your Schauer JAC1212-R battery charger.
Customer Support
For technical assistance, troubleshooting beyond this manual, or warranty claims, please contact Schauer customer support. Contact information can typically be found on the product packaging or the official Schauer website.







