Overview

The Hella Marine 178555924 is an H3 replacement bulb for 12V lighting with a 100W rating and a PK22s base.

It is used in halogen deck floodlights, searchlights, and other fixtures that specify an H3 bulb. Because 100W is a heavy load on a 12V circuit, confirm the light housing is rated for the wattage and that your wiring and switching can handle about 8.3A per lamp.

This is a straightforward service part for keeping an existing halogen light working without changing the fixture.

Key features

• H3 halogen replacement bulb for fixtures that take an H3 lamp
• 12V, 100W rating for applications that call for a high-wattage H3 bulb
• PK22s base to match standard H3 sockets
• Draws about 8.3A at 12V, which helps when checking fuse and switch capacity
• Useful when you want a like-for-like replacement and do not want to retrofit the light

Compatibility and fit

Match the bulb type and base to your existing lamp before ordering. The simplest check is the marking on the old bulb (H3) and the base style (PK22s). If your fixture uses a retaining clip or a specific lead connection inside the housing, make sure it lines up the same way before closing the lens.

This bulb is for 12V DC systems only. It should not be used on 24V circuits.

Installation and setup

Shut off power at the breaker or pull the fuse, then let the light cool fully before opening it. Halogen bulbs run hot, and the reflector and lens area can stay warm for a while after use.

Avoid touching the glass with bare fingers. If you do, wipe it clean before powering up so skin oils do not create hot spots on the quartz.

After reassembly, check that the gasket and lens are seated correctly so spray and washdowns stay outside the housing.

Electrical and system integration

At 100W, voltage drop becomes noticeable on long cable runs. Keep connections tight and corrosion-free, and size the circuit for the current draw of the lamp or lamps you are running. A quick functional check after install is steady brightness and no excessive heat at terminals or connectors.

Use on board

This bulb is a good match for boats that already have an H3 halogen deck flood or spotlight installed and want a direct service replacement. It is commonly used for dockside lighting, cockpit work, deck loading, and short-duration spotlighting where the existing fixture is already set up for an H3 lamp.

Maintenance and care

Halogen bulbs do not like moisture inside the housing. If you see condensation, address the seal or venting so the bulb is not stressed by repeated heat and cool cycles. Keeping the lens clean also helps the fixture run cooler for the same usable light.