I tried a phone with a battery over triple the size of the Galaxy S26 Ultra's

So, you want a smartphone with an incredible battery life. You shouldn't go out and buy the Samsung Galaxy S26 Ultra, iPhone 17 Pro Max, or even the OnePlus 15. There's a niche smartphone brand putting massive batteries inside Android phones, and its latest model has a capacity more than three times larger than the Galaxy S26 Ultra, iPhone 17 Pro Max, or Google Pixel 11 Pro XL. It's called the Oukitel WP70 Ultra, and it packs a whopping 16,000mAh battery into a (relatively) thinner frame.

You might remember Oukitel for making other wild Android phones. Last year, I tried the Oukitel WP63, a phone with an even larger 20,000mAh battery and a lighter that could start fires. This time, I went hands-on with the new Oukitel WP70 Ultra, and it's a more sensible, but still beastly, Android phone. While I prefer ultra-slim phones like the iPhone Air and Galaxy S25 Edge, if battery life really matters to you above all else, a phone like the WP70 Ultra might be for you.

Oukitel's WP70 Ultra outlasts your current phone

It has a gigantic silicon-carbon battery with fast charging

It's hard to appreciate just how large a 16,000mAh smartphone battery really is, so let's put it into context. The eSIM-only variant of the iPhone 17 Pro Max has a 5,088mAh battery. Samsung's Galaxy S26 Ultra has a 5,000mAh battery, while Google's Pixel 11 Pro XL has a 5,115mAh battery. All of these phone batteries use traditional lithium-ion chemistry with graphite anodes, and they're all less than a third of the size of the one inside the Oukitel WP70 Ultra.

Admittedly, we don't always get the best battery designs in the U.S. There's a newer version of lithium-ion batteries that replaces the graphite anodes with a silicon-carbon composite, and it allows the cells to be denser, cramming more capacity into smaller form factors. The Motorola Razr Fold and OnePlus 15 both use silicon-carbon batteries, and they have 6,000mAh and 7,300mAh capacities, respectively. You can enjoy true multi-day battery life with these smartphones, despite their slim frames. The OnePlus 15 is only 8.10mm or 8.2mm thick, which is thinner than both the iPhone 17 Pro Max and the Pixel 11 Pro XL.

The Oukitel WP70 Ultra also uses a silicon-carbon battery, but a much bigger one. That's how it's able to fit a 16,000mAh battery capacity into a smaller from factor than we've ever seen. Oukitel says this is the "slimmest 16,000mAh rugged smartphone," and while those caveats are doing a lot of work, it's still impressive. It charges at 66W speeds, too, which will help you recharge that gigantic battery. That's much faster than the WP63 I tried last year, that only charged at 33W with a cable.

It's thinner than other rugged, long-lasting handsets

It still might be twice as thick as your current phone

Oukitel's WP70 Ultra is by no means slim. It's likely twice as thick as your current phone, at least. However, in the context of these ultra-rugged phones, it's thinner than usual. This device exists in a category of outdoorsy phones you might not have heard of, and thinness isn't the goal. Instead, phones like the WP70 Ultra are designed to help you get through a camping trip or a survival situation — hence why the WP63, a similar device, has a built-in lighter.

The WP70 Ultra officially measures 16.4mm thick, so again, it's not going to break any records. If you think about it, a phone twice as thick as your current one with three times the battery capacity could be intriguing. Phones like the WP70 Ultra work best in specialized situations, rather than as an everyday device. For example, that 16,000mAh battery life could come in handy when using the WP70 Ultra's dual-frequency GPS for backcountry hiking.

Some of the phone's other specs are unremarkable, such as its MediaTek Dimensity 7200 processor. For the most part, the thick and rugged chassis is the biggest compromise. Or not, depending on who you are and why you're buying this phone. Otherwise, the 6.78-inch, 120Hz AMOLED screen looks great, and it ships with Android 16.

The Oukitel WP70 Ultra is full of tricks

This phone supports thermal imaging and has a 108MP primary shooter

The 16,000mAh battery is what first caught my eye about the WP70 Ultra, but the better feature might be thermal imaging. Yes, this phone has a thermal camera that can "identify risks and locate heat sources, performing reliably in total darkness, smoke, fog and harsh conditions." It's another tool that helps the Oukitel WP70 Ultra stand out in the world of rugged, extreme phones. Surprisingly, the WP70 Ultra also has a 108MP main camera and a 64MP night-vision camera.

Between the battery capacity, rugged design, and outdoorsy features, the Oukitel WP70 Ultra certainly offers something different than the flagships you're used to. We've seen really thin phones compromise battery life for a svelte look, and this phone shows off what devices on the opposite end of the spectrum look like. These phones compromise on thickness and weight to deliver incredibly long runtimes, durable chassis, and specialized features. If you think Android phones have become boring, think again.