A WHOOP alternative.
Powered by light.
Ray at a glance: Chargerless’s 7-gram, screen-free wrist tracker shows sleep, heart rate, HRV, temperature trends, steps/activity and light exposure in its companion app. Chargerless says about one minute of direct outdoor sunlight per day can sustain operation. Ray charges outdoors only. A full charge provides up to about 60 days of dark reserve. Ray focuses on everyday health signals, rather than WHOOP’s strain and recovery coaching.
Explore Ray
Which one fits your day?
Consider Ray if you want a light, screen-free bracelet for sleep and everyday health tracking, and would prefer to power it with light. Choose WHOOP if strain, recovery scores and established training coaching are central to how you exercise.
Both are screen-free, app-connected wearables. Ray’s health signals do not replicate WHOOP’s coaching system.
Ray, in a few useful facts.
- Weight
- 7 grams, as specified by Chargerless.
- Power
- Outdoor sunlight charging only. Chargerless says about one minute of direct sunlight outdoors per day can sustain operation, depending on exposure and use.
- Dark reserve
- Up to about 60 days in total darkness from a full charge, according to Chargerless. This is stored energy, not energy generated without light.
- What it tracks
- Sleep, heart rate, heart-rate variability (HRV), temperature trends, steps and activity, and light exposure.
- How you use it
- Wear the screen-free bracelet and view your health trends in the companion app.
- Limits
- Ray does not provide ECG or WHOOP’s strain and recovery coaching. Shared metric names do not establish equal measurement accuracy.
Ray specifications here are Chargerless’s own product claims, not independent head-to-head test results.
What changes from WHOOP?
| Your priority | Chargerless Ray | WHOOP 5.0 / MG |
|---|---|---|
| Power routine | Harvests light; needs sufficient exposure. About 60 days of dark reserve from full charge. | 14+ days per charge; rechargeable. |
| Wear experience | 7-gram, screen-free bracelet; details in the app. | Screen-free wearable; details and coaching in the app. |
| Everyday health | Sleep, heart rate, HRV, temperature trends, steps/activity and light exposure. | Sleep, heart rate, HRV and activity, with strain and recovery coaching; additional features depend on tier. |
| Training guidance | Focuses on everyday health signals; not a replacement for WHOOP’s coaching system. | The stronger fit when established strain, recovery and training guidance drive your choice. |
| ECG | Not available. | On-demand ECG on WHOOP MG with Life membership, for eligible users aged 22+ in supported markets; not on WHOOP 5.0. |
Room for a quieter routine.
If you want to wear a small bracelet, follow sleep and everyday health trends, and reduce the need to remember a charger, Ray is worth considering. Regular light exposure remains part of using it.
Room for more coaching.
If you plan workouts around WHOOP’s strain and recovery scores, switching means changing that workflow. Keep WHOOP on your shortlist if those scores, its coaching system or eligible MG ECG features matter more to you.
Before you switch.
Does Ray need sunlight every single day?
Not necessarily: its stored charge provides a buffer. Chargerless specifies up to about 60 days in darkness from a full charge. The one-minute-per-day claim refers to direct sunlight outdoors. Ray does not charge from indoor lighting.
Does Ray have a screen?
No. Ray is screen-free, and you view results in its companion app. WHOOP is also screen-free, so this is a shared feature rather than a Ray-only advantage.
Can Ray replace all WHOOP features?
No. Ray covers everyday signals including sleep, heart rate and HRV, but does not reproduce WHOOP’s strain and recovery coaching or the ECG available on eligible WHOOP MG plans.
Is this an independent review?
No. This guide is published by Chargerless, the maker of Ray. We link manufacturer sources below and separate specifications from buyer-fit judgments. We have not presented a controlled accuracy comparison between Ray and WHOOP.
Sources and scope.
Reviewed September 7, 2026. Hardware, features and purchase terms can change. Check each manufacturer’s current purchase terms before ordering. For Ray, review the purchase terms and Help Center, or ask us about phone compatibility before choosing.
- Chargerless technology and Ray product page: light harvesting, direct-sun claim, dark reserve, weight and tracking features.
- WHOOP Peak: WHOOP 5.0, battery and training/recovery features.
- WHOOP Life and WHOOP ECG guidance: WHOOP MG and on-demand ECG eligibility. Features vary by market and eligibility.