FIAMM 12FGL42 12 V 42 Ah AGM VRLA Battery

12FGL42 is a 12 V valve-regulated lead-acid battery from the FIAMM FGL general-purpose AGM range. The FGL folder lists it at 39 Ah for 10 hours to 1.80 volts per cell and 42 Ah for 20 hours to 1.75 volts per cell, both at 25 °C, in a 197 x 166 x 173 mm case of 14 kg.

A maintenance-free 12 V block sized for alarm, emergency and small solar duty

FIAMM describes the FGL series as maintenance-free AGM batteries with a lead calcium tin grid designed for a 10-year life and a short recharge time. The same text states that the sealed recombination design can be charged and discharged many times, so the 42 Ah block suits both standby and light cyclic service.

Within the family it sits in the middle of an 11-type ladder that starts at 12FGL27 (27 Ah, 8.8 kg) and ends at 12FGL210 (205 Ah, 62 kg). That position makes it a common replacement size for fire-alarm panels, emergency lighting inverters, access-control power and small off-grid stores.

What the FGL folder and the AGM manual state

• Case in recyclable ABS plastic; non-spillable and maintenance-free, with no water refilling.
• Classified non-hazardous for air, sea, rail and road transport, and installable upright or horizontal.
• Low self-discharge, which the folder presents as the reason FGL blocks suit long storage periods.
• Listed against IEC 60896 parts 21 and 22 and the Eurobat 10-12 years long life class; UL Recognized.
• Each cell has a one-way valve rated 15 to 30 kPa; glass-microfibre separators hold the 1.3 specific gravity electrolyte.

Technical specification

Data printed for 12FGL42 in the FGL folder

Charging values from the AGM engineering manual (apply to the range)

Derived values (calculated here, not printed)

Choosing 12FGL42 against its neighbours

The folder table gives 12FGL33 (33 Ah, 196 x 130 x 159 mm, 11 kg) below and 12FGL55 (55 Ah, 230 x 140 x 207 mm, 17 kg) above. 12FGL42 is the same 197 mm long as 12FGL33 but 36 mm wider, 14 mm taller and 3 kg heavier, so check the shelf before substituting.

Pick the 10-hour figure (39 Ah) when you size against a long autonomy and the 20-hour figure (42 Ah) when the load profile is lighter. Confirm the exact type code on the label before ordering.

Installation and charging notes from the manual

Keep 5 to 10 mm between blocks for heat dissipation, never lift by the terminals, and clean lids only with an antistatic cotton cloth. The manual recommends a 10 to 30 °C working range; the batteries operate from -20 to +50 °C, but life falls as temperature rises above 20 °C.

A VRLA block gasses very little at float: the manual quotes 2 ml per Ah per cell per month at 2.27 V. Cabinets must still breathe, so do not seal them. Shelf life is 9 months at 20 °C, 6 at 30 °C and 3 at 40 °C before a refresh charge is due.

Where small FGL blocks are specified in Oman and the GCC

The FGL folder names security and emergency, and renewable applications. In practice that covers fire-alarm and public-address panels, gate and barrier controllers and small solar stores. General engineering note: panel rooms and outdoor cabinets in the Gulf run hot, and the manual states that operation above 20 °C shortens life, so allow for derating in the design.

Related FIAMM items

Larger front-terminal blocks in the FIT and FHT2 families serve telecom racks, while the FG range covers the small end, 1.1 to 37.9 Ah according to the manual. The FIAMM engineering manual describes remote venting, racks and cabinets for the AGM family.

Battery room and maintenance notes

Lead-acid battery life falls quickly as temperature rises above the reference temperature in the manual, so keep small blocks out of hot ceiling voids and direct sun where possible. Use a charger with the float voltage and temperature compensation given in the manual, and check block voltages during routine maintenance.

When replacing blocks in existing equipment, match the dimensions, terminal type and capacity, and replace all blocks in a string at the same time.

Information to send with an enquiry

• Equipment and required backup time
• Quantity

Frequently asked questions

What capacity does 12FGL42 have?

39 Ah at the 10-hour rate to 1.80 volts per cell and 42 Ah at the 20-hour rate to 1.75 volts per cell, both at 25 °C.

What is the design life?

The FGL folder states a 10-year design life for the range.

What float voltage should I set?

The AGM manual recommends 2.27 volts per cell at 20 °C, which is 13.62 volts for this 6-cell block.

Can it be installed on its side?

Yes. The folder says FGL batteries can be installed in upright and horizontal planes.

Does it need water refilling?

No. The folder calls the range maintenance-free and the manual says VRLA blocks need no routine topping-up of electrolyte.

Documents and quotation

The official FIAMM datasheet and user manual for 12FGL42 are hosted on this page for download. Seven Star LLC is an independent supplier in Muscat; send your quantity and delivery location through the quotation form and we will quote this item. Please confirm the exact order code, supply voltage and output options against the documents before ordering. More related products: product category.