How do I know when I need to charge my blu PRO rechargeable device? 12 March 2020 11:06 You’ll need to recharge your blu PRO rechargeable device when the button on your device begins to blink red. Related articles When should I replace my blu PRO clearomiser? How long will a fully filled clearomiser last before I need to refill it? How do I know my blu PRO rechargeable device is charging and/or is fully charged? Why should I prime my blu PRO Kit Clearomiser and how do I do it? How long will it take to charge my PRO rechargeable device?