According to our experience, the number of assessments with the Nesplora tests that one could perform with the battery fully charged (100%) could reach approximately 6 administrations or more. 

Depending on the VR headset model, battery consumption varies. It is less in the Meta Quest 2 (10w) than in the 3 (18w), so, in principle, the duration in the Meta Quest 3 would be less. 

The charging cable can be used during assessments to increase autonomy, but it must be long enough to not interfere with the movements of the examinee. When charging your headset while wearing it, the charging speed may adjust to optimize battery performance considering certain factors, such as temperature. It is also possible that the battery in your headset may not fully charge if it is connected while wearing it and exceeds the optimal charging temperature. 

If you use a power adapter less than 18W to connect the headset to an electrical outlet, it will charge more slowly. Connecting it to a laptop or computer through a USB port that does not support the Power Delivery standard or has a recommended wattage capacity will slow down charging. 

There are also accessories, such as the elite strap, to increase the device's autonomy. For more information, see the following Meta Quest article: