Smart ring battery swelling: the warning signs and what to do

What to do right now

Steps 3 and 4 come from Oura's product safety page (Oura Support), which is the most detailed battery safety guidance we found from any ring maker. The rest is our own practical advice: when a battery might be damaged, the safe move is to stop using it, stop charging it and let the maker tell you what comes next. Until then, put the ring somewhere it can't be crushed and away from heat.

This page deliberately recommends no products. A ring that may be failing isn't a shopping moment, and the maker's support team, not a new purchase, is the right first call.

Warning signs worth acting on

We didn't find a support page from any ring maker that lists the symptoms of a swelling battery. So treat the list below as common-sense checks, not a brand's official list. Any one of them is reason enough to stop wearing the ring and ask the maker.

• A change in shape. A bulge, a raised or separated edge, or a crack or gap on the inside surface that wasn't there before.
• A fit that suddenly changes. The ring feels tighter or presses in one spot, though your finger hasn't changed and other rings still fit the same.
• A sharp drop in battery life or charging trouble. On its own, this is usually battery wear, not swelling. But Samsung's advice to Galaxy Ring owners facing “poor battery life or performance issues” is to contact its customer support, and that's sound advice for any ring.
• Discomfort you haven't felt before. Pressure, heat or soreness under the ring that doesn't match how it has always felt.

A ring that feels a little tight on a hot day isn't automatically a battery problem. Fingers change size through the day. What matters is a change in the ring itself, or a change in fit that other rings on the same finger don't show. If you're unsure whether your size was right to begin with, our smart ring sizing guide explains how each brand sizes its rings.

The Galaxy Ring case Samsung explained

The one smart ring swelling case we found with a manufacturer's explanation involved a Samsung Galaxy Ring. In January 2026, Android Police reported Samsung's findings: Samsung said the swelling in one owner's ring was caused by a crack in the ring's internal molding, and that there was “no wider product battery safety risk” (Android Police). Samsung also said users “facing poor battery life or performance issues should contact its customer support.”

What to take from it, and what not to. It's a single documented case with Samsung's own explanation, and we can't independently verify either the cause or Samsung's safety conclusion. It doesn't show that Galaxy Rings in general swell, and it doesn't show that other brands are immune. It does show that physical damage to a ring's structure is worth taking seriously, and that the maker's support line is the place to start. Our Samsung Galaxy Ring review covers the rest of that ring's record.

People also search for Oura and Ultrahuman battery swelling. We found no statement from either brand about a swelling case, and we don't report forum anecdotes as fact.

What's inside a smart ring

A tiny rechargeable battery, sealed in. Oura is the only brand we found that publishes the details: a “rechargeable, non-replaceable 15mAh (US6) - 22mAh (US13) Lipo battery.” RingConn says its batteries are “sealed inside the device and are not designed for user replacement” (RingConn).

Small as it is, that battery sits against your skin day and night, including while you sleep. That's why the handling rules matter more for a ring than for most gadgets, and why you should never try to open one to get at the battery. There's no user-serviceable part in there. How long those sealed batteries last, and which warranties cover them, is in our smart ring battery lifespan guide.

Heat, cold and saunas

Oura publishes a temperature limit: “extended exposure to extreme temperatures (below -20°C / -4°F or above 60°C / 140°F) may lead to battery damage.” That's the clearest temperature guidance any ring maker gives on the pages we checked. We didn't find an equivalent figure from the other brands we cover, so Oura's limits are a sensible benchmark for any ring.

Saunas are where people get confused. Oura's Ring 4 support page calls it “suitable for sauna and water sports but not diving” ( Oura Support). Its safety page warns about extended exposure above 140°F. Read the two together: Oura allows sauna use, but the word doing the work in the warning is “extended,” and Oura doesn't define how long that is. If you use a sauna often, check its thermometer against that 140°F figure, keep sessions short with the ring on, or take the ring off. Our guide to whether a smart ring is waterproof covers showers, pools and saunas brand by brand.

Cold counts too. The same Oura warning covers extended exposure below -4°F, and it applies to the ring whether it's on your finger or sitting in a bag. Treat the charging case the same way: it holds a battery too.

A ring designed to be cut off

One maker has designed for the worst case. Ultrahuman says its “ProRelease Technology” “enables Ring PRO to be cut apart more easily in the event of swelling or injury to the finger” (Ultrahuman). That's about a swollen finger, whatever the cause, not about the battery specifically. But it answers a real worry: what happens if a titanium ring has to come off in a hurry.

We didn't find a similar statement from Oura, RingConn, Samsung or Circular on the pages we checked. That doesn't mean their rings can't be removed by a professional, only that they don't advertise a design for it. Either way, cutting a ring off is a job for medical staff, not something to try at home, and it's exactly the situation where Oura says to stop trying and seek medical attention. More on the Ring PRO in our Ultrahuman Ring PRO review.

Battery problems that aren't swelling

Most battery trouble is duller than swelling. Android Authority reported in September 2026 that Oura's pre-IPO filing tied an increase in warranty expenses during fiscal 2025 to Oura Ring 4 battery problems (Android Authority). That report is about battery performance. It doesn't mention swelling, and we don't read it as evidence of any.

If your ring simply runs out faster than it used to, with no change in shape or fit, that's battery aging or a fault, not a safety emergency. It's still worth a call to support, and our smart ring battery life guide shows what each maker says a charge should last, so you can tell how far off yours is.

Contacting the maker

When you contact support about a suspected swollen battery, have these ready. It speeds things up and helps with any warranty claim:

• Your order number and where you bought the ring (the brand's store or Amazon).
• Clear photos of the ring, especially the inside surface and any bulge, gap or crack.
• When you first noticed the change, and whether it happened while charging.
• Your ring size and model, including the generation.

Don't post the ring back or throw it away until the maker tells you how. A damaged battery may need special handling in shipping and disposal, and the maker is the one who can tell you what that is. How each brand's warranty handles batteries, and what the return windows are, is in our smart ring warranty and returns guide. Every other battery, sizing and fit guide is on the battery and sizing hub.