A few months back I reviewed the Brando Power Jacket case for the Nokia Lumia 920. A case with a built-in battery, it could potentially double the battery life of the Lumia 920 – a dream for gamers. But the Brando case didn’t perform all that well as a charger, limiting its usefulness.
Enter Mugen Power, makers of many external batteries and cases. At long last, Mugen now offers an extended battery case for the Nokia’s original flagship Windows Phone 8 handset. The Mugen Power Battery Case for Lumia 920 comes in black or white, as well as two different battery capacities: 3000 mAh and 4700 mAh. The 4700mAh model offers 2.35x extra power on top of the 920’s built in battery. I’ve spent the last few weeks using that version as my case in order to bring you this detailed review.