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Dark Energy Reservoir review

iPhone-sized battery packs lots of punch

Dark Energy Reservoir

Our Verdict

A solid, portable external battery that's easy to use


  • Slim and light
  • 8,000mAh capacity
  • Charges 2 devices simultaneously


  • Slightly expensive
  • Comes in only one color

Dark Energy is probably wondering when battery technology will keep up with the rest of, well, everything else. Perhaps that's why we have the Dark Energy Reservoir, an 8,000 mAh battery pack that's just a little bigger than an iPhone.

Dark Energy Reservoir review

The Dark Energy Reservoir is a small brick of a battery - think of the Mophie Powerstation Duo, but slimmer and taller with more capacity - with just a few ports. Two USB ports are used for charging your devices, and the microUSB port between them is used for charging the device itself.

Dark Energy Reservoir review

Using the Reservoir is easy: when the battery pack is fully charged, you simply plug your USB cables into it and onto your phone or tablet. It can charge two devices at once, which is nice, but that'll suck the power out of the Reservoir a little quicker.

Dark Energy Reservoir: Painfully easy to use

Once your devices are plugged in, you just press the power button on the Dark Energy Reservoir and they'll start charging. If there aren't any devices connected and you press the power button, the light indicators will glow to show you how much juice is left in the thing. There are three dot lights, each dot represents about 33% of battery life.

That's really all there is to this thing. Having 8,000mAh in a slim, pocketable device is greatly convenient, especially at a time where our smartphones are getting even greedier for more juice.

Dark Energy Reservoir review

My only gripe with the Dark Energy Reservoir is the price. At $129, it's quite expensive. The Mophie Powerstation Duo, with 12,000mAh is the same price, but you get more capacity. Sure, the Mophie is a bigger, fatter battery pack, but at this point if you really need the battery life, you're probably not going to care for extreme portability.

Dark Energy Reservoir review

But if money is no object, you can't go wrong with the Reservoir. It's easy to use, it looks nice and it'll give you confidence when you leave the house or office that your phone or tablet won't die on you.