This concept Android phone is slim and lasts nearly a week per charge
How'd Realme cram a 15,000mAh beast into a phone this skinny?

What you need to know
- Realme's got a wild concept phone with a 15,000mAh battery, which is bigger than the batteries in an iPhone 12 through 16 combined.
- The company claims it could last five days on a single charge, let you game for 30 hours straight, or even charge your other gadgets because it's basically a power bank with a screen.
- That giant battery is just a proof-of-concept for now and isn't ready for mass production.
Chinese phone makers like Realme, Honor, and Oppo are using silicon-carbon anodes to push battery limits. The boldest example so far is Realme's new concept phone: it's surprisingly thin but holds an extremely huge battery.
At its recent 828 Fan Festival in China, Realme introduced two new concept smartphones. One of these devices features a huge 15,000mAh battery, which is claimed to allow users to watch 25 movies or play games for 30 hours on a single charge.
Introducing realme's Game-Changing Concept Phones! Say hello to the future:realme 15000mAh – with the INDUSTRY’S LARGEST phone battery!realme Chill Fan Phone – the WORLD’S FIRST "AC" phone!No more charging anxiety , no more overheating warnings —just pure, unstoppable power… pic.twitter.com/6orC36s3kXAugust 27, 2025
Most phones with batteries this large, like our favorite rugged phones, end up thick and heavy. Realme's somehow sidestepped that entirely. The company squeezed a monster battery into a chassis that's just 8.89mm thick, making the typical tough phone look ancient by comparison.
According to Realme, its battery holds more power than all five iPhone models from the 12 to the 16 combined. It's also pitching it as a portable charger you can use to power up your other devices, like your smartwatch or a friend's phone, with a cable.
A total marathoner
So what does that get you? Realme estimates about five days of regular use, enough video playback to binge for two straight days, or it could just sit in your bag on airplane mode for a quarter of a year.
The major limitation is that the 15,000mAh battery isn't feasible to mass-produce yet, as per leaker Digital Chat Station. However, Realme has a 10,000mAh version of this tech that may already be in production, making a real-world release far more likely.
Here's the catch
For now, don't expect to buy this beast. Realme is just testing the waters with this concept, and it'll probably only greenlight a mass-market version if people are genuinely excited about it.
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Not stopping at just a giant battery, Realme also unveiled its Chill Fan model. This one tackles a different problem: heat. It comes with an integrated cooling fan to keep performance smooth during heavy gaming, so your phone doesn't turn into a hotplate.
You can spot a vent on the phone's left side in the teaser image, most likely acting as an exhaust. According to the company's VP, this active cooling setup is powerful enough to cool the device by up to 6°C.
Realme threw everything at overheating with this concept. The cooling system is a three-part combo: a huge vapor chamber soaks up the heat, a tiny fan spins to dissipate it, and a thermoelectric cooler gives it that final chill push.

Jay Bonggolto always keeps a nose for news. He has been writing about consumer tech and apps for as long as he can remember, and he has used a variety of Android phones since falling in love with Jelly Bean. Send him a direct message via X or LinkedIn.
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