AI Glasses Battery Life: Charging and All-Day Wear Explained

Key takeaways 

• Smart AI glasses last between 24-48 hours on standby
• Some components, such as cameras, draw more power
• AI glasses are limited by their design, needing to balance battery size with comfort
• There are two types of smart glasses charging: magnetic cables and charging cases
• HTC VIVE Eagle can charge to 50% in 10 minutes

What is good battery life for smart AI glasses?

Good battery life for AI glasses means lasting at least a day - batteries range from 160-250mAh, meaning between 2-4 hours of audio, 1-3 hours of calling and between 24-48 hours of being left on standby before needing a charge.

AI glasses are most useful when they last at least a single day in mixed use. This can be particularly important for people using the smart spectacles with prescription lenses, as it will interrupt their day if they have to repeatedly take off their spectacles for charging.

Comparison table

Device Battery capacity Manufacturer-stated battery life

Even Realities G2 192 mAh Up to 2 days typical use

Rokid AI glasses style 210 mAh Up to 12 hours

Meta Ray-Ban Gen 2 210 mAh Up to 8 hours typical use

Meta Ray-Ban Display 248 mAh 6 hours mixed use

HTC VIVE Eagle 235 mAh 4.5 h music / 3 h calls / 36 h standby

Meta Ray-Ban Gen 1 160 mAh 4h mixed use

* Battery-life figures are manufacturer-stated estimates and may reflect different testing conditions and usage patterns. Actual battery life varies by use, settings, connectivity, environmental conditions, and other factors

Battery life in smart AI glasses is a balancing act - ensuring that as much power can be held inside the frames, without making them uncomfortable to wear. 

According to a study of AI wearables, most glasses weigh between 15-40g. The plastic frames of smart glasses, without the components like processors, microphones and batteries, weigh around 20-30g, meaning the between 20-30g of extra weight comes from the internal electronics.

This means the amount of power that can be drawn from the battery is limited by the device, and as such, comes down to how each brand makes the components work together efficiently.

Some components and functions require significantly more power than others. Camera use, particularly continuous video recording, can be especially power-intensive.

That’s why it’s important to be able to interpret the different battery life times - ‘all-day’ use, which is critical in AI glasses, means glasses being mostly on standby with intermittent use of things like music and playback and voice calling mixed in.

Standby, music and voice call times explained

Standby refers to the device being turned on, but there is no activity. Music is when the open-ear audio speakers are emitting noise, and voice calling is where you’re connected to a smartphone and conducting a call.

The HTC VIVE Eagle offers 4.5 hours of music playback, 3 hours of calling and 36 hours of standby - but why are they all so different?

Why does standby last so long?

In this state, almost everything is asleep. Only one microphone is active, listening for the wake word from the user, and there’s a low-power sensing core ready in case the system needs to be woken up.

Why do calls only last around 3 hours? 

During calls, the device uses its microphone array and audio-processing features, including beamforming and echo cancellation, which increases power consumption compared with standby operation

Feature table

During Music During a call

Microphones Single microphone for wake word All microphones firing at once

Beamforming Not needed Yes - all microphones need to be directed to get the best sound

Echo cancellation No Yes - all microphones work from different positions to eliminate echo

Radio Receiving (A2DP) Sending and receiving audio

What does a full day of battery life look like? 

Mixed use battery life means using AI glasses for a variety of things. In typical mixed use, VIVE Eagle may spend significant periods in standby between activities such as listening to audio, taking photos, making calls, and using AI features. Actual battery life will vary significantly depending on which features are used, how frequently they are used, device settings, connectivity, environmental conditions, and other factors.

It’s important to realize that intermittent use is what will get your AI glasses to last the day - if you want extended music listening in the office, need to record many meetings or are shooting video every hour, you’re going to need to top up.

That’s why it’s important to have AI glasses that allow you to keep using them, even if you’re undertaking power-intensive tasks.It’s also key that smart glasses don’t waste power unnecessarily - for instance, HTC VIVE Eagle will automatically turn off after two hours of inactivity if the battery life dips below 60% by default. However, you can alter this in your settings, giving control over how you manage the power drain on your glasses.

How do you charge AI glasses?

There are two methods of charging smart glasses: through magnetic pogo pins, as found on HTC VIVE Eagle, which means you can clip a charging cable onto the arm of the device.

Others, such as Meta Ray-Ban Display or Even Realities G2, use a charging case. While this provides more power on the go, it means users need to wait until they can use the glasses again.

HTC VIVE Eagle users can also buy a Power Boost - an 8g small battery that attaches to the side of the glasses and tops up around 45-50% of the battery while still wearing them. 

How long do AI glasses take to charge?

Under specified charging conditions, VIVE Eagle can charge from approximately 1% to 50% in about 10 minutes and to 80% in about 23 minutes. Charging time may vary based on temperature, charger, battery condition, and usage.

Charging speeds may decrease as the battery approaches full capacity in part to manage heat and protect battery performance and user comfort. The product safety standard IEC 62368-1 has guidelines that some elements in smart glasses can’t exceed 48°C if they’re in contact with human skin.

However, most manufacturers will keep this below 40°C to keep things comfortable - meaning charging has to slow to reduce the heat.

Can you use AI glasses while charging?

Whether AI glasses can be used while charging depends on the device and charging method Those that use magnetic pogo pin charging, like the VIVE EAGLE, allow you to wear them while on charge, while others that use a case will need you to wait until they’ve picked up enough juice to continue.

Smart glasses battery tips: how to maximise time between charges

AI glasses’ battery life can be improved if you follow these tips on using your device efficiently:

1. Using the AI button to activate the onboard LLM, rather than saying the wake word and firing up the microphone
2. Synchronise video when charging, rather than wearing the AI glasses, as Wi-Fi connectivity is one of the more power-intensive components
3. Top up batteries in shorter bursts - studies show that topping up regularly to 50% can prolong overall battery life 2-3x
4. Don’t leave smart glasses in direct sunlight, as this can cause the battery to discharge more quickly
5. Use moderate volume - this is good for the health of your ears (versus always listening to very loud volume), but as most open-ear audio uses smart sound management designated to direct audio toward the wearer while minimizing sound leakage