Routine cleaning
After regular outdoor use, wipe the body with a soft damp cloth and dry it. After heavier exposure — rain, snow, mud, salt water — take a moment longer:
- Rinse the exterior with fresh water to remove salt or fine grit before it works into the threads or O-rings.
- Dry the body, head, and tail-cap with a soft cloth.
- Open the light, wipe the threads with a clean dry cloth, and inspect the O-rings.
- Apply a thin film of silicone grease to the threads and O-rings before reassembling.
Threads and O-rings
The waterproof seal on a Fenix light depends on the O-rings at the head and tail-cap. They need a small amount of silicone grease to stay pliable. A thin film — not enough to be visible — is the right amount. Replace any O-ring that has flattened, cracked, or stretched. Replacement O-rings are inexpensive and can be requested through the contact form by model.
Threads benefit from the same light grease. Gritty threads are abrasive and over time wear the O-rings against the body. Wipe them clean whenever the light has been used in dust, snow, or sand.
Tail-cap maintenance
The most common service issue on a Fenix light is a corroded or dirty tail-cap switch. Service it once a year, and immediately after any heavy weather:
- Remove the tail-cap from the body.
- Inspect the inside of the tail-cap for green or white residue. If present, clean with isopropyl alcohol on a cotton swab.
- Inspect the spring contact. It should compress evenly and return to full extension. If it has lost tension or is corroded, the tail-cap needs replacing.
- Wipe the threads. Apply a thin film of silicone grease.
- Reassemble.
Charging port
On lights with a built-in USB-C port, keep the rubber port cover seated when the light is not charging. The cover provides the waterproof seal; leaving it flapping defeats the IP rating. If the cover tears or comes loose, contact us — covers are typically a warranty replacement.
Inspect the port itself for lint and debris before plugging in. A wooden toothpick clears most of it; never insert metal into a USB port.
Storage between uses
For a light that goes weeks or months between uses:
- Bring the cell to about half charge (≈50%) before storage.
- Loosen the tail-cap a quarter turn to lock the light out electrically.
- Store at room temperature, away from direct sun, in a dry place. Avoid the unheated garage or shed in winter.
- Check on it every six months. Top up the cell if needed; cycle the switch and modes briefly to confirm everything still works.
Maintenance schedule
| When | What |
|---|---|
| After every use in rain, snow, mud, or salt water | Rinse, dry, inspect O-rings, regrease threads. |
| Monthly, on a daily-carry light | Wipe down, check the tail-cap and head are tight, confirm the cell holds charge. |
| Twice a year, on any light | Full clean, tail-cap service, fresh silicone grease on threads and O-rings. |
| Annually | Inspect O-rings; replace if flattened or cracked. Inspect the cell for swelling or torn wrap; replace if degraded. |
What not to do
- Do not use petroleum-based grease on O-rings — it swells the rubber and breaks the seal.
- Do not over-tighten the head or tail-cap. Snug is enough; cranking it down deforms the threads and the O-rings.
- Do not run a light at maximum output continuously. Most Fenix lights step down on their own to protect the LED, but a light held at turbo against a hard surface can overheat. Keep airflow around the head when using high modes.
- Do not disassemble the head of the light. The head holds the LED and the optic in a sealed assembly; opening it voids the warranty and almost always damages the optic.