This dehumidifier from Hydrosorbent includes an inbuilt recharge indicator. The indicator is at first orange in color, however it turns by itself crystal clear when it demands a reactivation. Also, this merchandise doesn’t need any power supply to function, which implies it may work without having a battery or cord. https://dstdehumidifiers.co.uk/case-studies/desiccant-dehumidifiers-in-cold-stores/