You can replace the battery in most Timex watches yourself in about 10 minutes with a few basic tools. The specific method depends on whether your watch has a snap-off case back (common on Weekender and many Expedition field watches) or a screw-down case back (found on some Expedition and sport models). Digital models like the Ironman use a slightly different process because of their resin cases and multiple buttons. Here’s the practical step-by-step for all three families, with clear checkpoints so you know when the job is done right – and when to stop and hand it to a jeweler.
What You’ll Need Before You Start
Gather these tools and supplies before you open the case:
- Case opener – For snap-backs: a plastic pry tool or a small flathead screwdriver (covered with tape to avoid scratching). For screw-down backs: a case-back wrench, adjustable opener, or a rubber ball for grip.
- Tweezers – Plastic or brass tweezers to avoid shorting the battery.
- New battery – Common Timex batteries: SR621SW (for many Weekender and Expedition analog models), SR920SW (some Expedition), CR1616 or CR1620 (for Ironman digital models). Always check the reference number printed on the old battery – never guess.
- Soft cloth – To protect the crystal and watch face.
- Spring bar tool – To remove the strap or band if needed (optional but recommended for easier handling).
Decision checkpoint: If your watch has a screw-down case back, you must have a proper opener – don’t try to force it with pliers. If it’s a snap-back, a simple pry tool works, but be careful not to gouge the case.
Step-by-Step Battery Replacement
Step 1: Remove the strap (optional but smart)
Flip the watch over and use a spring bar tool to depress the spring bars holding the band. Removing the band gives you clear access to the case back and reduces the risk of scratching the strap.
Step 2: Open the case back
Place the watch face-down on a soft cloth.
- Snap-off case back: Insert your pry tool into the small notch at the edge of the case back. Gently twist or pry upward – the back should pop off. Work around the edge if needed.
- Screw-down case back: Use your case wrench or rubber ball to turn the back counterclockwise. Don’t use excessive force; if it’s stuck, try a few drops of penetrating oil around the seam.
Checkpoint: Before you remove the battery, take a photo of its orientation (which side is facing up) and note the battery reference number printed on it. This saves you from guessing later.
Step 3: Remove the old battery
Use tweezers to carefully lift the battery out. Avoid touching metal parts inside the watch (the movement or circuit board). Set the battery aside – you’ll need the number to buy the correct replacement.
Step 4: Insert the new battery
Place the new battery in the same orientation as the old one. Most analog Timex watches have the positive (+) side facing up. For Ironman digital models, check the printed markings inside the battery compartment. Use tweezers or a wooden toothpick to position it without touching the contacts.
Friction point: If the battery compartment has a small metal spring or spacer washer, make sure it’s seated correctly before inserting the battery. Losing this piece will prevent the watch from working.
Step 5: Close the case back
- Snap-off: Align the back with the notch (if any) and press firmly around the edge until you hear a click. Apply even pressure – don’t hit it.
- Screw-down: Thread the back clockwise by hand until it’s snug, then give it a light final turn with your wrench. Avoid overtightening – you can strip the threads or crack the crystal.
Step 6: Verify function – concrete check
Press the crown on analog models to start the watch. For digital models, press any button to wake the display. Set the time and test the INDIGLO backlight. What to look for: The second hand should tick steadily at one-second increments – if it jumps in two-second intervals, the battery is low or not making solid contact. On digital models, the display should show all segments briefly and then hold steady time. If the watch runs but the light flickers or dims, reseat the battery and ensure the contact spring is clean.
Common Mistakes and How to Avoid Them
| Mistake | Why it matters | How to avoid |
|---|---|---|
| Using the wrong battery size | Won’t fit or won’t power the watch | Match the exact reference number from the old battery |
| Damaging the gasket or O-ring | Loss of water resistance (50-meter rating gone) | Inspect the rubber gasket; replace if cracked or dried out. Lightly lubricate with silicone grease |
| Touching battery contacts with metal tweezers | Can short the circuit | Use plastic or brass tweezers |
| Overtightening a screw-down back | Stripped threads or cracked crystal | Tighten only to snug – no extra force |
| Forgetting the battery orientation | Watch won’t start | Take a photo before removal |
For a real-world example, the Timex Men’s Expedition Scout 40mm Watch – Black Case Cream Dial with Green Fabric Strap uses a snap-off back – typical for analog Expedition models. Open it with a plastic pry tool, replace the SR621SW battery, and press the back on firmly. The Timex Men’s Expedition Acadia 40mm Watch – Triple Black uses a similar case construction.
In contrast, the Timex Men’s Expedition 41mm Watch – Black Strap Digital Dial Green Case (digital model) has a resin case with a screw-down battery hatch – you’ll need a small Phillips screwdriver to access the battery.
When to Stop and Take It to a Jeweler
Not every battery change goes smoothly. Stop your DIY attempt and go to a jeweler if:
- The case back is heavily corroded or won’t budge after moderate effort.
- You see battery acid leakage (white or green powder inside) – acid can damage the movement and requires cleaning.
- The watch stops again within a few days – the movement may have a deeper electrical issue (e.g., a dead capacitor or shorted coil).
- The watch is an heirloom or a vintage model – a jeweler can replace the battery and pressure-test the watch afterward.
- You snap a spring bar or strip the case-back threads during reassembly.
For most Timex Weekender, Expedition, and Ironman watches under $100, a DIY replacement is safe and cost-effective. But if you run into any of these red flags, a jeweler will charge $10–$20 for the service, which is cheaper than replacing the watch or paying for movement repair.
Frequently Asked Questions
How often should I replace the battery on my Timex Weekender or Expedition?
Expect 1–2 years on analog models (depends on how often you use the INDIGLO light). Digital Ironman watches typically last 2–3 years.
Can I replace the battery in my Timex Ironman myself?
Yes – most Ironman models use a CR1616 or CR1620 coin cell under a screw-down hatch or snap-back. Be careful with the gasket and ensure the buttons are properly lined up when reassembling.
My watch stopped working after a battery change – what did I do wrong?
First, confirm the battery is fresh and installed with the correct polarity. Then check that the metal battery clip or spring is making good contact. If the watch still doesn’t run, the movement may have been damaged by static or a short – in that case, replacement is usually more economical than repair.
Do I need to remove the stem or crown to change the battery?
No – most Timex quartz watches allow battery access without removing the stem. Only older or water-resistant models with a movement tray might require it, but this is rare. If you see a screw or clip holding the movement in place, leave it alone and take the watch to a jeweler.
If the watch works after reassembly and the time keeps accurate, you’re done. Give the case back a final check to ensure it’s fully seated – water resistance depends on a tight seal.
The We Know Watches editorial team brings together over 40 years of combined watch collecting, trading, and repair experience. Our editors have owned and handled watches from every major brand — from entry-level Seiko 5s to Rolex, Omega, Patek Philippe, and independent Swiss watchmakers. We’ve bought and sold at auction, worked with authorized dealers, visited manufacturing facilities in Switzerland and Japan, and serviced hundreds of movements ranging from the Seiko 7S26 to the Longines L888. Every guide and review we publish is based on hands-on experience, original research, and consultation with professional watchmakers. We do not accept payment for reviews, and we clearly disclose when we use affiliate links.