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Need a smartphone that keeps going and going? This one can last over 3 months

The Energizer Hard Case P28K has a massive 28,000 mAh battery, but with great battery capacity comes great size. It's not for the faint of pockets.
Written by Adrian Kingsley-Hughes, Senior Contributing Editor
Energizer 28,000mAh Phone at MWC 2024
Kerry Wan/ZDNET

I've seen smartphones with some pretty big batteries, the biggest probably being the Doogee S100 Pro with its colossal 22,000mAh battery. But a new smartphone unveiled at MWC 2024 has that one beat.

This week, Avenir demoed a new smartphone at Mobile World Congress in Barcelona called the Energizer Hard Case P28K. It's basically a phone that's built around a power bank.

Also: I tried the Samsung Galaxy Ring and it beats the Oura in 2 meaningful ways

Confused about the name? That's understandable. Avenir has licensed the Energizer name from the battery manufacturer. 

The spec sheet for the Energizer Hard Case P28K is rather bland: 

  • 6.78-inch, 1080p LCD display
  • Android 14
  • MediaTek Helio G99 MT6789 octa-core processor
  • 8GB RAM
  • 256GB storage, 
  • 60-, 20- and 2-megapixel rear camera
  • 16-megapixel front-facing camera
  • 4G support (no 5G)
  • IP69 rating

But then you get to the battery, and things get weird!

Also: This is the most rugged Android phone I've tested, and it can last 2,350 hours

The battery is a mammoth 28,000 mAh battery, giving the handset a talk time of almost 5 days, and a standby time of close to 100 days.

Energizer 28,000mAh Phone vs Samsung Galaxy S24 Plus

Energizer 28,000mAh Phone vs Samsung Galaxy S24 Plus

Kerry Wan/ZDNET

That's nuts! 

But with great battery capacity comes great size. This thing is 1.1 inches thick, or to put that another way, three times the thickness of an iPhone 15, and it weighs 1.25 pounds. Unless you've got big, deep, pockets (and a good belt) this thing isn't going in your pocket. 

Also: The most jaw-dropping demo at MWC was from a brand I wasn't expecting to see

I did some digging around on this, and it seems that it's planned to go on sale in October and will cost about $270. However, and somewhat oddly, Avenir doesn't have plans to release this behemoth in the US. 

So if you want to get your hands on a smartphone with a giant battery today, then the Doogee S100 Pro is the handset for you (and it's currently on sale for nearly 30% off on Amazon Prime). It's the same thickness, but lighter (0.88 pounds) so it's a little easier on your pockets. It also offers up to almost 98 days of standby time.

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