Watts up: Xiaomi's new charger fills up your phone in just five minutes

With MWC 2023 underway we're already experiencing an avalanche of some of the best new phones from everybody, but one of the most interesting demos isn't something you can buy – yet. Xiaomi has demonstrated its latest generation of fast charging, with a Redmi-branded 300W charger that can take a 4,100mAh battery from zero to full in one second under five minutes.

300W is a lot. The previous charging record was held by Realme with a 240W model, and now Xiaomi has raised the bar even further. 

However, we've no idea when this charging tech will make it into mass production – if it makes it into mass production at all.

What's the secret of Xiaomi's super-fast charger?

In a phrase: MORE POWER. Its previous fastest charger was a 210W model, and Xiaomi has found a way of taking that up to 300W without making it physically bigger thanks to improved heat dissipation design.

It's certainly fast – from zero to 20% in about a minute, to 50% in two and to full charge in four minutes 59 seconds – and that's in part due to better battery technology, with new carbon materials that reduce the thickness of the battery's electrolytes and a new formula that enables higher power density and faster charging with reduced heat. 

My first thought on looking at the demo was that the battery must get as hot as the sun: fast charging my iPhone 14 makes it feel warm enough to fry an egg on. But Xiaomi says no: it has put in over 50 different safety features to monitor the voltage, current and temperature to ensure it doesn't burn a hole through to the centre of the earth.

If you're wondering why such brilliantly clever tech might not make it into production, the answer is in what Xiaomi isn't talking about: the battery's longevity. Generally speaking, the more powerful the charging the fewer years you'll get out of your battery.

I do think that for most of us, we're already way past the point where fast charging is fast enough already: many of the best Android phones can get a few hours of extra life from a few minutes charging, which is ideal for panicky bus or train charging after a long day. Me, I'd rather have a battery that lasts longer than one that charges quickly. But that doesn't make for quite so exciting headlines.