36V external battery module for Symphony 1.5kVA UPS

The Symphony EBM3618RT2U is a 36V external battery module designed by Uniti Power to extend the runtime of the Symphony SPY1500RMi2U 1.5kVA online UPS. It holds maintenance-free sealed lead-acid batteries in a 2U rack/tower case, and up to four modules can be connected to one UPS, taking typical full-load runtime from 3.3 minutes on internal batteries to 64.8 minutes.

Where servers, network switches or security systems need to keep running through an outage longer than the UPS's internal batteries can cover, adding EBM3618RT2U modules increases battery autonomy without changing the UPS power module. Runtime grows with each module fitted, so a system can be sized to the site's continuity plan now and extended later as the protected load changes.

Key specifications

• Battery voltage: 36V DC, matching the battery system of the SPY1500RMi2U.
• Battery type: maintenance-free sealed lead-acid.
• Format: 2U rack/tower, 438 x 445 x 85.5mm (W x D x H).
• Weight: approx. 22.6kg.
• Maximum per UPS: four external battery modules.
• Replacement batteries: two URBK1 replacement battery kits per module.
• Environment: 0-40°C operating temperature, 0-95% relative humidity, 0-3000m altitude.

Typical runtime with the SPY1500RMi2U

Runtimes are typical values for new, fully charged batteries at 25°C, provided as a guide only. Actual runtime depends on battery age, temperature and the type of load.

Rack or tower installation

Rack ears and tower feet are supplied, so the EBM3618RT2U can be mounted in a 19-inch cabinet with the UPS or stand alongside it as a tower. The EBM cable is included, and a rail kit is available as an option for rack installations. The Symphony Range Brochure describes the Symphony external battery packs as hot-swappable.

For the best battery life, keep the module in an ambient temperature of 20-25°C. Operation outside this range may reduce battery life and performance. Uniti Power also offers installation and commissioning for Symphony systems.

Warranty and support

The EBM3618RT2U carries a 2-year warranty. See warranty information for full terms, or contact technical support for help planning a battery configuration.

What's in the box

EBM3618RT2U battery module, EBM cable, rack ears, tower feet and user manual. A rail kit is optional.

EBM3618RT2U questions answered

Which UPS is the EBM3618RT2U designed for?
The Symphony SPY1500RMi2U 1.5kVA online UPS. The EBM3618RT2U is a 36V module matched to that model; the Symphony 3kVA SPY3000RMi2U uses the 72V EBM7218RT2U instead.

How many EBM3618RT2U modules can be connected?
Up to four EBM3618RT2U modules can be added to one SPY1500RMi2U.

How much runtime does one EBM3618RT2U add?
With one module, the SPY1500RMi2U gives a typical 15.3 minutes at the full 1500W load and 37.0 minutes at 750W, compared with 3.3 and 8.7 minutes on internal batteries.

Which replacement batteries does the EBM3618RT2U use?
Two URBK1 replacement battery kits replace the batteries in one EBM3618RT2U.

How do I buy the EBM3618RT2U?
Request a quote on this page, call 0845 561 0560, or find a Uniti Power partner near you.

Specifications are taken from the Symphony External Battery Modules Datasheet (PDF). Runtime figures are taken from the Symphony Range Brochure (V1.2025, PDF).