Mugen has recently announced an extended battery case designed for the Sony Xperia Z3 in mind. The battery case itself comes with a 3,700mAh battery under the hood which is 600mAh more than the battery in the Sony Xperia Z3, meaning that you should get a full charge and then some for those emergencies.
Now the case will not come cheap as Mugen has priced it at $89.50, so unless you absolutely need the extra battery, you could save yourself a fair bit of money, but if you want that peace of mind knowing that your phone won’t die on you while you’re out and about, then $89.50 could be a small price to pay for such a convenience.
As it stands the Xperia Z3 packs a 3,100mAh battery under the hood which is a pretty big one. Sony is boasting a 2 day battery life, although most tests conducted have revealed that it falls short of 2 days, but it comes pretty close which is still good enough, but for those who travel often and don’t have access to charging ports, battery cases are a good alternative.