Certina DS Podium Battery Replacement

The Certina DS Podium Watch Battery Hack (AKA Solving the Renata Battery Problem).

Learn how to replace a hard-to-find watch battery with a common one. If you own a Swiss watch, especially a Certina, you’ve probably run into this issue. The official battery is often a specific silver oxide cell made by Renata. For my Certina DS Podium chronograph, that’s the Renata 394 (also marked SR936SW).

These batteries can be surprisingly difficult to find locally, and when you do find them, they can be overpriced. Even the common replacement, the Varta VR394, can be elusive. I have a big set of Polaroid button cell batteries, but it didn’t have the right size.

Let me show you how I used a different, more common battery to get my watch running again.

Why This Battery Is So Hard to Find

The correct battery is a 1.55V silver oxide cell, model 394. It’s a Swiss-made Renata battery with specific markings: 394 and SR936SW.

For some reason, these aren’t stocked in regular supermarkets or electronics shops in many places. You usually have to go to a watch shop or jeweler, where they charge a premium, or order online and wait.

What You’ll Need for This Hack

• A small watch case opening tool (a cheap set from online works).
• A set of small screwdrivers.
• A fresh, common battery. I used an LR41 (also known as AG3 or 384).
• A clean, well-lit workspace.
• Optional: Tweezers and a bit of plastic from packaging.

Step 1: Opening the Watch Case

This is often the trickiest part. First, remove the watch band to make it easier to work with. My band has telescopic arms held by small spring bars. I used a paperclip to press in the ends and release them.

• Find the notch on the watch case back. It’s a small lip where you can fit your tool.
• Use the watch case opener. Insert the flat edge of the tool into the notch.
• Apply gentle, steady pressure to pop the back off. Be careful not to slip and scratch the case (I’ve done this before!).
• Once open, carefully lift the back off and set it aside.

Important: Inside, you’ll see a rubber gasket. This is for water resistance. Try not to damage it. For a proper seal, you should apply silicone grease when reassembling, but I didn’t have any on hand.

Step 2: Accessing the Battery Compartment

With the back off, you’ll see the watch movement. Don’t touch any of the tiny gears or mechanisms (the “red zone”).

• Look for a small metal cover or clamp holding the battery in place. On my watch, it was held down by two tiny screws.
• Use your smallest screwdriver to carefully remove these screws. Keep them in a safe container so they don’t get lost.
• Gently lift the metal clamp or cover. You can use a plastic spudger or a bent paperclip to help.

Step 3: The Battery Swap

Now you can see the old Renata 394 battery.

• Remove the old battery. Note its orientation (which side is facing up).
• Here’s the key part: The LR41/AG3/384 battery I’m using has the same thickness (height) as the Renata 394, but a slightly smaller diameter. This means it will fit in the compartment, but it might be a little loose.
• Place the new LR41 battery into the compartment with the correct side facing up (usually the positive, flat side).

Step 4: Securing the New Battery

Because the new battery is a bit smaller, it can move around. We need to make sure it stays in contact with the terminals.

• You can simply put the metal clamp back over it. The pressure from the clamp is often enough to hold it in place, even if it’s not a perfect fit.
• For extra security, I cut a very small sliver of thin plastic (from product packaging) and placed it between the battery and the edge of the compartment. This acts as a shim to prevent the battery from sliding.
• Carefully replace the metal clamp and screw the two tiny screws back in. Don’t overtighten them.

Step 5: Testing and Reassembly

Before you close everything up, it’s crucial to test.

• The second hand on my watch started moving immediately, which was a good sign.
• Gently press the case back onto the watch. It should snap into place with firm, even pressure all around.
• Reattach the watch band using the spring bars.

Does It Work? Final Thoughts

Yes, it works perfectly. The voltage of the LR41 (1.5V) is very close to the original silver oxide cell (1.55V), and the watch runs without issue. The smaller diameter isn’t a problem as long as the battery is held firmly in place by the clamp.

Learn how to do this to save yourself a trip to the jeweler and the wait for a special-order battery. This is a great hack if you need a quick fix and have common LR41 batteries on hand.

A quick disclaimer: This will likely compromise the watch’s water resistance, especially if you don’t re-grease the gasket. I don’t recommend swimming with it after this. Also, be very careful with the tiny screws and delicate parts. If you’re not comfortable, it’s always best to take it to a professional.

But if you’re in a pinch, this simple swap can bring your favorite watch back to life in just a few minutes.