A fitness tracker without a charging cable
Ray uses light to replenish its battery, so you have one less charger to remember. A short time in sunlight can replace a day’s energy use, while stored power carries it through darker days.
The charger is easy to forget
You take off your tracker to charge it, leave it on a desk and remember it after your walk. Or you pack the tracker for a trip and leave its charging cable at home.
When the battery dies, the record stops. The inconvenience is not just plugging it in; it is losing the sleep, activity or heart-rate data you wanted to collect.
How Ray stays powered
Ray collects energy from light while you wear it. Under our test settings, about 1–2 minutes in direct sunlight replenishes one day of use. Outdoor shade takes about 10–15 minutes. Bright daylight beside a window takes roughly an hour.
Those are daily top-ups, rather than full-charge times. Weather, angle, clothing and settings affect how much energy the device collects. Ordinary room lighting is not enough to sustain it.
You can find the conditions together in the Ray charging guide.
What happens on darker days?
A full battery gives Ray about two months of reserve, depending on settings and use. You do not have to hit a sunlight target every single day. The reserve gives you room for days spent indoors, covered wrists and changes in routine.
A simpler habit
Keep an eye on the battery level in the app and let the device see daylight regularly. A daytime walk or a little time outside can become part of keeping it powered.
For people tired of managing another cable, that is the appeal: health tracking that fits into the day instead of adding another charging task.