FMA PVS-31 Functional Battery Case with IR — Desert

The PVS-31 Functional Battery Case is a battery compartment with integrated IR lights, designed to mount on a helmet via velcro and functionally replicate the power and infrared signalling systems of PVS-31 night vision devices. The compact dimensions — 85x40x88 mm — allow stable placement on the shell without interfering with side-mounted accessories.

The power circuit handles two to four AA batteries split into two groups (A and B) connected in partial series: as long as at least one battery per group is delivering current, the unit operates, with a controlled output voltage between 2.0 and 3.5 V. Gold-plated contacts reduce contact resistance and oxidation over time; dust-proof seals protect the internal compartments in sandy or humid environments. The use of rechargeable batteries is not recommended by the manufacturer.

On top of the unit are two IR emitters with a strobe function, operating at a wavelength between 820 and 850 nm: invisible to the naked eye, they are clearly distinguishable through an image intensifier or a near-infrared-sensitive camera, making them useful for position identification in total darkness. The asymmetric selector is designed to be operated by feel, with no need to look at the control panel. Empty weight is 90 g: the trade-off is straightforward — the system adds IR capability to any velcro-equipped helmet, but total weight increases noticeably once four AA batteries are fitted, and the overall height can interfere with optics or cameras mounted on top of the shell.

Key points

• The two 820–850 nm strobe IR emitters allow position identification in complete darkness via image intensifiers or NV cameras, without revealing your position to anyone without night vision.
• The dual-group series circuit maintains operation even with one depleted battery per group, improving reliability during extended use.
• The quality velcro on the back provides a secure hold on the helmet without requiring any structural modification, while still allowing quick removal.
• Gold-plated contacts and dust-proof seals reduce corrosion and fouling issues in dusty or humid environments.
• The asymmetric selector allows blind operation with gloves, without having to visually locate the button.

In the box

• FMA PVS-31 Functional Battery Case with IR