WEARABLE TECHNOLOGY
Energy harvesting for wearable devices
By Bruno Damien, ecosystem & partners marketing director, e-peas R
ecent years have seen a massive rise in the number of wearable devices used for B2B security (e.g., access badges), healthcare (e.g., vital sign monitors) and sports/consumer applications. IDC reported a 9.1 per cent YoY growth for 2025, and Grand View Research predicts a 12.1 per cent CAGR from 2026 to 2033, with both highlighting the creation of novel form factors and use in a growing array of applications.
However, being battery-powered, these devices come with notable limitations. While consumer devices such as smart watches can be recharged at home and on the go with few serious consequences, this is not the case for B2B devices. These instead require organisations to dedicate resources to ensure they are charged, or batteries checked/replaced – with battery failures leading to staff being locked out, or health data lost.
The use of disposable batteries also creates design and e-waste implications, either requiring IP6X protection to allow battery replacement without affecting water resistance, or using sealed designs that last only as long as the battery.
That’s not to say rechargeable batteries are the answer. They have a limited number of charge/discharge cycles, and performance noticeably degrades over time. Like in a phone, these effectively create a programmed obsolescence, or require oversized storage elements, bulky form factors and high costs.
Rechargeable batteries will also require a recharge port (typically 5V USB), which again creates further complications when implementing IP6X protection. Projects such as the Effector European collaborative research project are leading energy harvesting ecosystems, especially photovoltaic cells, storage element technologies and their associated power management ICs. These advances are enabling fully sealed, lightweight devices that can run continuously without recharging or battery replacement.
CardLab’s battery-free biometric smart cards developed under the Effector project implement an OPV energy harvesting cell, managed by e-peas’ PMICs, for sustainable operation. Source: CARDLAB Innovation Aps
System requirements
Wearables need to be small/lightweight and have tight power budgets. Their MCU, data transmission, display, sensors, security and other PCB or software elements must take these into consideration. This makes many of them ideally suited for powering from ambient energy.
Eliminating disposable batteries in these devices requires three elements: a harvester (photovoltaics, etc.), storage (Li-ion cell or supercapacitor…) and a PMIC to maximise and extend the storage element’s life. Recent years have seen several notable advances in PV performance, with DSSC, III-V, Amorphous and Organic cell technologies enabling far greater energy extraction than previous generations. More recently, hybrid PV technologies are allowing operations at light, allowing extension toward higher energy production.
In response, PMICs have also evolved, with capable of managing the full dynamic range of these hybrid and outdoor scenarios was launched by e-peas at the end of 2025. For the storage element, advances miniature SMD formats. and other lithium free storage elements, in place of oversized AAA or coin cells.
The assumption that battery-based designs is the cheapest option is also fast-
22 MAY 2026 | ELECTRONICS FOR ENGINEERS
becoming a fallacy. For OEMs, the cost of implementing energy harvesting has parity with disposable batteries; and that’s before the 9.7 per cent “sustainability premium” that consumers are willing to pay is factored in.
Implementation
When migrating, we need to consider both the system’s power requirements and the energy available from the range of environments in which it will be used, including day-night cycles. This will set the type and size of both PV and storage. Minew’s MTB11 access tag houses a 30x25mm PV, plus storage and e-peas PMIC alongside the MCU and Bluetooth transceiver within a 4mm thick unit that’s two-thirds the size of a credit card and runs for over 10 years.
As part of the Effector project, e-peas is working with Polar to implement health tracking for nurses and care workers, supercapacitor to power a smartphone- compatible arm band that combines movement and vital-sign sensors in one, and Cardlabs to develop a self-powered access badge.
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