How much does the battery capacity of AI glasses fade after one or two years?

A customer who bought her Even G2 from us about eighteen months ago came back recently with a matter-of-fact observation: the charging case, which reliably delivered seven full charges when it was new, now gets her six, some days five. "Is that normal, or is something wrong with my unit?" she wanted to know. The honest answer: that is exactly what you should expect — from practically any device with a lithium-ion battery, not just the G2.

The starting point: 192 mAh, brand new

The manufacturer's figure of roughly two days of typical use and about seven full case charges applies, like almost every battery-life claim in the industry, to a fresh unit under controlled conditions. How that runtime shifts across different day-to-day usage profiles — heavy translation and teleprompter use versus occasional notifications — is a question we cover in detail elsewhere. This piece asks something different: not how far the battery gets you in a single day, but how that range changes over months and years as the cell ages.

How lithium-ion batteries age — the physics behind it

Lithium-ion cells age in two ways at once, and both are well documented for any device built around one. The first is cycle aging: every charge and discharge slightly changes the electrodes, and those small changes add up over hundreds of cycles into a noticeable capacity loss. The second is calendar aging: the cell loses capacity simply with the passage of time, even with light use — and this process speeds up markedly with heat, and when the battery sits near 100% or near 0% for extended periods. That is why a two-year-old phone left in a hot car ages visibly faster than one kept cool and charged moderately — and the same principle applies to the cell inside AI glasses.

What does that mean concretely for your G2 after one year, after two?

We are deliberately cautious here: we have no Even-specific measurement stating the G2 loses X percent of capacity after twelve months. Anyone who hands you a precise figure without a source is probably making it up. What can be said responsibly is a qualitative expectation: after a year of regular daily use, some decline in capacity is normal, usually still barely noticeable. After two years, a clearly perceptible difference from new is plausible — shorter runtime per day, fewer full charges from the case — much like what you would expect from a two-year-old smartphone. That is not a malfunction or cause for alarm; it is the normal life curve of a lithium-ion cell. How pronounced the effect is on your particular unit depends heavily on your usage and, above all, on heat exposure, covered next.

Care that noticeably slows the aging

1. Heat is the single biggest accelerant. Do not leave the glasses or case on a sunny windowsill, in a glovebox, or on a car dashboard. This is the factor most clearly shown to speed up calendar aging.
2. Do not leave them permanently at 100% or 0%. Over longer breaks — say, a holiday without the glasses — a cell ages more slowly if it is brought to a middling charge level rather than left full or empty for weeks.
3. Charge normally instead of always deep-discharging. You do not need to run the battery down to zero every time before charging. Frequent, moderate top-ups are generally gentler on the cell than regular full cycles.
4. The case matters too. The case's own battery is also a lithium-ion cell and ages by the same rules. Protect it from heat as well — otherwise the number of full recharges it can deliver drops regardless of the glasses' own condition.
5. Store at partial charge if unused for weeks. If the glasses will sit unused for an extended period, a middling charge level before storing is gentler than leaving them fully charged or fully drained.

These care notes describe generally accepted lithium-ion battery principles, the same ones that apply to smartphones and laptops. They are not Even-specific instructions; for binding guidance on the G2, ask Even or your reseller.

How to tell your battery has aged noticeably

A simple, everyday indicator: if the case initially delivered around seven full charges and now clearly delivers fewer, or if the glasses run out noticeably faster than in the first weeks under the same usage, that is a normal sign of aging — not cause for panic, but a good moment to take the care tips above more seriously. We are not aware of an official Even diagnostic tool that shows battery health as a percentage. If you notice a sudden, drastic drop rather than a gradual decline over months, that is more a matter for the reseller or Even directly than a normal aging pattern.

So: buy, skip, or know before you buy?

Buy with confidence if you accept that every lithium-ion cell — in your phone, your laptop, and also in AI glasses — loses some capacity over years. That is industry-standard behaviour, not a quirk specific to the G2.

Think twice if you expect a firm guarantee that runtime stays unchanged for years. No manufacturer of a lithium-ion device offers that guarantee, and we would not promise you one we cannot back up.

Ask before you buy about the one thing no general guide can settle for you: what update and service history Even can show for the G2, and how your reseller handles a case of unusually early capacity loss. Ask that directly at the Zürich showroom, and take a look beforehand at our buying guide as well as the specs of other models in the AI glasses database, if longevity is a purchase criterion for you.

Disclosure: AI-Eyewear is the authorised Swiss reseller of Even Realities. The aging notes are general lithium-ion physics, editorially framed — not a measured or published capacity curve for the G2 from Even.