The world’s largest battery in a smartphone—a 28,000 mAh, 27-mm-thick brick

Four years ago, Avenir Telecom made headlines with an "Energizer"-branded phone that sported a massive 18,000 mAh battery. This year, the company is back at Mobile World Congress with another pocket-busting brick phone with an even bigger battery: 28,000 mAh.

The phone is called the Energizer Hard Case P28K. Avenir Telecom doesn't seem to have a webpage or press release about it, and there is only one official picture, but The Verge saw the phone at the show. Avenir is not reaching these massive battery sizes through any kind of magic; the old 18,000 mAh phone was 18 mm thick, and this 28,000 mAh phone is a whopping 27.8 mm thick. That's more than three iPhones stacked on top of each other. It's more like a battery bank with a phone attached to it. Actually, there's a good chance this is a row of 18-mm-thick 18,650 batteries, plus normal 9-mm-thick smartphone hardware on top. The 570 g weight makes it more than three times the weight of an iPhone, too.

The Energizer battery brand is not well-known for working with phones, but Avenir Telecom licenses the brand and pumps out all sorts of weird niche phones under the name. Lately, it has been making dumbphones. This one is a ruggedized IP69 smartphone with big rubber bumpers. On top of that giant battery, you'll find a pretty crusty budget phone. The display is a 6.78-inch 1080p LCD. The SoC is a MediaTek MT6789, aka the Helio G99—that's a 6 nm, eight-core SoC with two cortex A76 CPUs and six A55 CPUs, and it's 4G-only. You'd be hard-pressed to find a slower chip shipping in new phones. It also has 8GB of RAM, 256GB of storage, Android 14, and 33 W charging.

With all that battery, Avenir promises some ridiculous run-time stats: a week of "normal usage"; five days, or 122 hours, of talk time; and standby of 2,252 hours, or 94 days!

Just like last time, there's the strong smell of vaporware coming off this phone. The only mention of the phone on Avenir's website says the device is "pending Energizer final approval," which doesn't inspire confidence. The Verge reports it will be sold internationally in October for 249.99 euros. If you don't want to wait, a power bank and a roll of duct tape sounds like a good stand-in.