Dell's Wireless Keyboard And Mouse Last All Day On A Quick 5-Second Charge
This isn't a gimmick, and it isn't a joke; plug the keyboard and mouse in, go make a cup of coffee, and come back to fully charged input devices with up to three months (keyboard) or six weeks (mouse) of battery life. Or, if you pull them out of your laptop bag and they're dead, plug them in for just five seconds to get all-day battery life. It basically obviates battery life and charging as concerns, entirely.
How is this possible? Supercapacitors. This keyboard and mouse do not have a 'battery' in the conventional sense; no alkaline cells or lithium-ion pack here at all. Instead, the 'battery' in these devices is a supercapacitor. Supercapacitors have a ton of advantages over regular batteries: they tolerate huge numbers of charge/discharge cycles with very little wear, and they accept and release charge thousands of times faster than chemical batteries.
So what's the downside? Well, they're drastically less dense, so they don't hold as much charge. That's the main reason why we don't use them in more devices; the power draw of most electronics will empty a supercapacitor many times faster than a lithium battery. However, mice and keyboards require extremely little power to begin with; modern input electronics are drawing milliwatts under use and far less when idle. This is arguably a perfect use case for supercapacitors.
This is not to undersell Dell's engineering, though; implementing supercapacitors into consumer devices is tricky. Voltage drops considerably as they discharge, so you need to design a boost converter circuit with high-efficiency smart power management that accommodates for that while still allowing the device to take advantage of the characteristics of supercapacitors. There's a reason you haven't seen many devices designed like this; it's complicated and challenging.
If you're sold on supercapacitor input devices, hold your horses a bit. Dell hasn't provided pricing, but it probably won't be cheap; the standard Dell Pro 7 Slim setup, which takes AA/AAA batteries for a 3-4 year runtime per swap, runs $89.99, and supercaps ain't cheap. We expect that this combo will run at least $149 when it launches on April 16th, at least here in North America. The price could be worth it if you never have to replace it, though.
