Why Smart Ring Batteries Keep Failing: The Systemic Problem Behind the Swelling, Drain, and $84 Million Warranty Bill

If you’ve been following the smart ring industry closely over the past few months, you’ve probably noticed a disturbing pattern.

In September 2026, Oura confirmed that certain Ring 4 units had genuine battery performance problems, contributing to an $84.4 million increase in warranty expenses. In February 2026, a Samsung Galaxy Ring user reported that their device’s battery swelled up—months after it had stopped holding a charge—and became physically stuck on their finger. Samsung has now received over 200 battery-related complaints, with at least 12 involving swelling.

These aren’t isolated incidents. They’re symptoms of a systemic problem that affects every smart ring on the market—and understanding why could protect both your finger and your wallet.

1. The Physics of a Battery That Doesn’t Fit

Let’s start with the fundamental engineering challenge.

A smart ring is roughly 2 to 3 millimeters thick. To fit a battery, a sensor array, a Bluetooth chip, and an antenna into that space, manufacturers have to use ultra-dense lithium polymer cells. To maximize battery life, many brands have adopted silicon-carbon anode materials—a chemistry that offers higher energy density but has significantly worse cycle stability. Over-discharging or overcharging can trigger gas generation and swelling.

This is not a design flaw unique to one brand. It’s a physics problem that every manufacturer faces. The smaller the battery, the more sensitive it becomes to heat, physical stress, and charging cycles.

And here’s where the problem gets worse: most smart rings are hermetically sealed with medical-grade epoxy. This makes them waterproof and durable—but it also means the battery cannot be replaced. Once the battery degrades or swells, the entire device becomes hazardous electronic waste.

2. The “Ticking Time Bomb” Scenario

The most alarming battery-related incidents don’t happen during normal use. They happen when users continue wearing a dead ring.

One Reddit user bought their Galaxy Ring in July 2024. About nine months later, the battery stopped holding a charge entirely. Instead of seeking a warranty replacement, they kept wearing the dead ring for nearly a year—because they’d gotten used to the feeling on their finger. When they finally tried to charge it in February 2026, the battery had swelled so badly the ring wouldn’t fit on the charger.

This is what makes smart rings uniquely dangerous. With a phone or a pair of earbuds, a swollen battery means you stop using the device and dispose of it. With a ring, the device is attached to your finger. A YouTube creator experienced this firsthand when his Galaxy Ring’s battery swelled during a flight. His finger became swollen and discolored, and he was denied boarding because the situation could have escalated into a medical emergency.

Samsung’s official guidance is clear: if you experience battery or performance issues, stop wearing the ring immediately and contact support. But many users don’t realize their ring is malfunctioning until it’s too late.

3. Why Battery Life Declines Faster Than You Expect

The second battery problem is less dramatic but far more common: rapid capacity decline.

Smart rings typically advertise 5 to 8 days of battery life. In practice, many users report that this number drops significantly within the first year. A TikTok creator threw her Oura Ring in the trash after realizing its battery only lasted six hours per charge—down from the advertised multi-day lifespan. Her post racked up over 4.3 million views, with hundreds of commenters sharing similar experiences.

A Samsung Galaxy Ring user reported that after just one month of use, their ring needed daily charging. Another user swapped their ring four times within four months due to battery drain issues.

These aren’t unusual cases. Battery degradation is accelerated by several factors: frequent deep discharges, high-temperature charging, and the inherent instability of the silicon-carbon chemistry used to cram more energy into a tiny space.

4. What Oura’s $84 Million Disclosure Tells Us

The most significant development in this story came from Oura’s IPO filing. The company disclosed an $84.4 million increase in warranty expenses during fiscal 2025, directly tied to battery performance problems affecting certain Ring 4 units.

To Oura’s credit, the company replaced affected rings for free—and in some cases, even provided replacements after the standard one-year warranty had expired. That’s a more generous response than many consumer electronics companies offer.

But here’s the critical gap: Oura hasn’t revealed which Ring 4 batches were affected. The filing mentions “certain groups of Ring 4 devices” without identifying purchase dates, sizes, serial numbers, or other details that could help owners determine if their ring is at risk. If you own a Ring 4 and notice sudden or unusually fast battery drain, you have no way of knowing whether you’re holding a defective unit or simply experiencing normal degradation.

5. How to Protect Yourself

Here’s what every smart ring owner should do:

Monitor your battery behavior. If your ring suddenly starts draining from 100% to 50% in a few hours—or if it stops holding a charge altogether—that’s not normal. Contact support immediately. Don’t wait.

Never wear a dead ring. If your battery has completely failed, remove the ring and store it safely. Don’t keep wearing it out of habit. A dead battery can swell over time, especially if left in a discharged state.

If your ring swells, do not try to force it off with water or soap. Use oil or a lubricant instead. Forcing a swollen ring can cause injury.

Push for warranty coverage. Oura has replaced affected Ring 4 units even after the warranty period in some cases. Samsung’s official guidance is to stop using the ring and contact support. If you’re experiencing battery issues within or near the warranty window, document everything and escalate if necessary.

Keep your firmware updated. Manufacturers release firmware updates that optimize charging algorithms and improve power management. Interrupted updates can leave your ring running inefficient background processes that accelerate battery drain.

The Bottom Line

The smart ring industry has a battery problem. It’s not a conspiracy—it’s a consequence of cramming energy-dense batteries into a form factor that leaves no room for safety margins, no room for repair, and no room for error.

Some brands are handling it better than others. Oura’s decision to replace affected rings beyond the warranty period is a meaningful commitment. But the lack of transparency about which units are affected leaves millions of users in the dark.

Your ring is a tool. It should serve your health, not threaten it. Monitor your battery, act quickly when something changes, and remember: a ring that won’t hold a charge is not just an inconvenience—it’s a safety signal you shouldn’t ignore.