Anyone who travels frequently has at some point noticed how dependent we are on our gadgets, and even more so when we’re far from home. Flat battery is the last thing you would hope for when on the go, but should you run into trouble a decent power bank could save your day.

Power banks are portable extra batteries or external chargers that are insanely useful when you’re on the road and don’t have where to charge your mobile devices. Or better said, they are helpful if you have done your homework before purchasing one. So, what should you know when choosing the best power bank for travel?

1.Find out the battery capacity of the mobile device you need to charge. Your power bank should have a battery that’s at least the same size as your gadget battery. That way you can charge your device fully at least once. Of course, you can play it safe and take much bigger one, but the more capacity you want, the more you usually have to pay. So think about what you really need when you travel. For example my iphone 6 has a 1810 mAh battery and I’ve been doing just fine with a 2000 mAh power bank.  How much you need depends also on how fast your device is consuming the battery. For a big power consumer I would go for a bigger power bank.

2.Check the charger specifications of your gadget’s original charger. The output current of the power bank should be equal to or higher than the output of the original charger. Usually this is given in amps or milliamps, like 1A, 1000mA or 2.1A. The higher the output current is, the faster your device gets charged, provided your gadget is able to accept a higher current. If the output is lower your device will consume more power than it gets from the power bank and you’ll end up with a dead battery.

If you need to charge several mobile devices on the go, you might want to check how many ports and cables the potential power bank is equipped with. It’s a time saver to be able to charge more than one gadget at a time. And naturally, the power bank’s battery capacity needs to be adequate for all your gadgets’ needs.

Lastly, for users who appreciate security and long lifespan, couple of features might be essential. Short circuit protection cuts the power when short circuit occurs preventing the power bank from catching fire. In addition, overcharge protection cuts off the electricity when the power bank is fully charged. Otherwise continuing charging it would shorten the battery life.

There, hope these tips get you at least started with picking your external battery pack. But if you’re not ready yet to make the decision on your power bank, don’t worry; there are usually some things you can do to make your mobile device consume less power.