1. Introduction
This manual provides essential information for the safe and effective use of your SigmasTek ER-HM450 UPS Replacement Battery. Please read these instructions carefully before installation and retain this manual for future reference. This battery is designed as a direct replacement for the Energizer ER-HM450 model, ensuring compatibility and reliable performance.
2. Safety Information
Observe the following safety precautions to prevent injury or damage to the battery and connected equipment:
- Battery Type: This is a Sealed Lead-Acid (SLA) battery with Absorbent Glass Mat (AGM) technology. It is maintenance-free and designed with spill-proof construction.
- Handling: Do not short-circuit the battery terminals. Avoid dropping the battery or subjecting it to severe impacts.
- Charging: Only charge the battery using a charger or UPS system designed for sealed lead-acid batteries. Refer to the operating instructions for specific charging parameters.
- Ventilation: While sealed, ensure adequate ventilation during charging to dissipate any potential gas buildup.
- Disposal: Do not dispose of batteries in fire. Batteries contain hazardous materials and must be recycled or disposed of according to local regulations.
- Temperature: Operate and store the battery within recommended temperature ranges to ensure optimal performance and lifespan.
3. Product Overview
The SigmasTek ER-HM450 is a high-quality, brand new, factory-fresh replacement battery designed for Uninterruptible Power Supply (UPS) systems. It features Absorbent Glass Mat (AGM) technology, providing a maintenance-free and spill-proof design. The battery is U.L. Recognized and CE Certified, ensuring compliance with safety and quality standards.

Image 1: The SigmasTek ER-HM450 UPS Replacement Battery. This image displays the battery's front view, showing the SigmasTek branding, model number SP12-3.5 (12V3.5AH/T1), and essential charging instructions for floating and cycle use.
4. Setup and Installation
This battery is intended as a replacement unit. Follow the instructions provided by your UPS manufacturer for safe battery replacement. It is crucial to use the existing cables and hardware from your original UPS battery to connect the replacement unit.
- Power Down: Ensure your UPS system is completely powered off and disconnected from the main power supply before beginning the replacement process.
- Access Battery Compartment: Open the battery compartment of your UPS unit as per its instruction manual.
- Disconnect Old Battery: Carefully disconnect the existing battery, noting the polarity (positive and negative terminals). Disconnect the negative terminal first, then the positive.
- Remove Old Battery: Extract the old battery from the compartment.
- Insert New Battery: Place the SigmasTek ER-HM450 replacement battery into the compartment, ensuring proper orientation.
- Connect New Battery: Connect the positive terminal first, then the negative terminal, using the existing cables and hardware. Ensure connections are secure.
- Close Compartment: Securely close the battery compartment.
- Initial Charge: Connect the UPS to the main power supply and allow it to charge the new battery fully before relying on it for backup power. Refer to your UPS manual for initial charging times.

Image 2: The SigmasTek ER-HM450 UPS Replacement Battery with key dimensions. This image provides measurements in both inches and millimeters, which are crucial for verifying fit within your UPS battery compartment.
5. Operating Instructions
Once installed, the SigmasTek ER-HM450 battery operates as an integral component of your UPS system. The UPS unit manages the charging and discharging cycles of the battery. For optimal performance and longevity, adhere to the charging instructions printed on the battery label and your UPS manufacturer's guidelines:
- Floating Use Voltage: 13.5V to 13.8V
- Cycle Use Voltage: 14.4V to 15.0V
- Initial Charging Current: Less than 1.05A
Ensure your UPS system is configured to these parameters if adjustable. Typically, UPS systems are pre-set to manage SLA batteries correctly.
6. Maintenance
The SigmasTek ER-HM450 battery features a maintenance-free design. Regular user maintenance is minimal, but the following practices can help ensure its longevity:
- Keep Clean: Periodically inspect the battery terminals and connections for dust or corrosion. Clean with a dry cloth if necessary.
- Storage: If storing the battery separately, ensure it is fully charged and kept in a cool, dry place away from direct sunlight and extreme temperatures. Recharge every 3-6 months during prolonged storage to prevent deep discharge.
- UPS Checks: Follow your UPS manufacturer's recommendations for periodic self-tests or battery calibration to monitor battery health.
7. Troubleshooting
If you experience issues with your UPS system after installing the replacement battery, consider the following:
- UPS Not Holding Charge:
- Verify that the battery connections are secure and correctly polarized.
- Ensure the UPS unit itself is functioning correctly and is capable of charging the battery. Consult your UPS manual for diagnostic procedures.
- Confirm that the UPS is receiving adequate input power.
- Short Runtime:
- Ensure the battery has undergone a full initial charge cycle.
- Check the load connected to the UPS; excessive load can reduce runtime.
- Battery performance can be affected by extreme temperatures.
- Incorrect Fit: If the battery does not fit, double-check the dimensions provided in the specifications section against your UPS battery compartment.
For persistent issues, refer to your UPS system's troubleshooting guide or contact the UPS manufacturer's support.
8. Specifications
| Attribute | Value |
|---|---|
| Model | ER-HM450 (SP12-3.5) |
| Brand | SigmasTek |
| Product Dimensions (L x W x H) | 5.24 x 2.64 x 2.36 inches (133 x 67 x 60 mm) |
| Item Weight | 2.9 pounds |
| Battery Cell Composition | Lead Acid (AGM) |
| Voltage | 12 Volts (DC) |
| Capacity | 3.5 Ampere-hours (Ah) |
| Color | Black |
| Manufacturer | SigmasTek |
| Certifications | U.L. Recognized, CE Certified |
9. Warranty and Support
The SigmasTek ER-HM450 UPS Replacement Battery comes with a 1-year warranty from the date of purchase. This warranty covers manufacturing defects and ensures the battery is brand new and factory fresh upon delivery.
For warranty claims, technical support, or further inquiries, please contact your retailer or the manufacturer, SigmasTek, directly. Please have your purchase receipt and battery model information available when contacting support.





