Yuasa SWL+850FR Industrial VRLA Battery - 12V / 28.8Ah (Flame Retardant / High Rate Performance)

The Yuasa SWL+850FR is the high-end safety version of the powerful SWL+850 monobloc. It combines an exceptionally high capacity of 28.8 Ah (C20) with a housing of the highest fire protection class (UL94 V-0).

This 12V battery was specially developed for critical UPS applications in sensitive environments (data centres, banks, hospitals). It offers maximum energy density in the compact footprint of a standard 24Ah battery while meeting the strictest safety requirements. With a service life of 12+ years the SWL+850FR is the ultimate upgrade for compact UPS systems.

Highlights at a glance

• FR safety housing (Flame Retardant): The case and lid are made of flame-retardant ABS plastic according to the UL94 V-0 standard. In the event of a fire, the material self-extinguishes and prevents burning dripping – a must for many server rooms.
• Maximum capacity (28.8 Ah): With almost 29 Ah, this unit offers approx. 20% more energy than standard batteries of the same size (e.g. NPL24-12). This enables significantly longer backup times without loss of space.
• SWL+ power upgrade (850 watts): The number "850" stands for the increased power output (watts per block). The battery is optimised to safely handle the high inrush currents of modern IT loads.
• Eurobat "Very Long Life": Classified for a service life of 12+ years (design life up to 15 years). This minimises the total cost of ownership (TCO) due to extremely long replacement intervals.
• HT Element X Technology: The special lead-calcium-tin alloy reduces internal corrosion and self-discharge. This makes the battery resistant to ageing, even during years of standby operation.
• Maintenance-free & Safe: VRLA-AGM technology (Absorbent Glass Mat). The electrolyte is bound in the fleece, the battery is leak-proof, vibration-resistant and does not require topping up with water.

Areas of application

The SWL+850FR is designed for compact systems with the highest safety and performance requirements:

• UPS systems (UPS): High-performance upgrade for rackmount UPSs and external battery modules.
• Safety lighting: Central battery systems in public buildings (fire protection!).
• Telecommunications: Mobile phone stations and outdoor enclosures.
• Medical technology: Protection of critical equipment.
• Security technology: Fire alarm panels and alarm systems.

Technology & advantages

The SWL+850FR offers technical features that set it apart from standard batteries:

1. Dense packing: Advanced grid designs allow more active mass to fit into the standard case (166 x 175 x 125 mm), enabling the jump from the usual 24Ah to 28.8Ah.
2. Flame retardancy: While standard cases (UL94 HB) may burn, the V-0 plastic ensures that the battery does not become a source of fire or propagate flames.
3. Recombination: The sealed system recombines gases into water. No acid escapes, making it safe for use in office environments or IT racks.

Installation & safety instructions

• Connection: The battery has M5 internal thread. The recommended tightening torque is 2.5 Nm. Use suitable tools to avoid damaging the thread.
• FR requirement: If your installation specifies FR batteries, you may not use standard batteries (HB) as a replacement. Never mix FR and non-FR batteries in a string.
• Installation position: Standing or lying on the side possible (not upside down).
• Charging voltage: 2.275 V/cell ±1% at 20°C (corresponds to 13.65 V block voltage).

Features

FAQs about the Yuasa SWL+850FR

Does the SWL+850FR replace the NPL24-12FR?

Yes, and it improves the system.

The mechanical dimensions are identical. However, the SWL+850FR offers 28.8 Ah (instead of approx. 24 Ah) and a longer service life (12+ years instead of 10 years). So you get more runtime and durability with the same space requirement and the same safety (both FR).

What does "FR" mean and why do I need it?

"FR" stands for Flame Retardant (flame retardant). In public buildings, airports and professional data centres, fire protection certificates and insurance often require that all plastics used are self-extinguishing (UL94 V-0) to minimise the fire load.

Will this battery fit in my UPS cassette (RBC)?

Most likely yes.

Many UPS manufacturers (such as APC, Eaton etc.) use standard blocks of the size ~24-28Ah in their battery cassettes (RBCs). If your old batteries were approx. 16.5 x 17.5 x 12.5 cm and had M5 connections, the SWL+850FR is the perfect high-performance replacement.