Having a way to charge your iPhone on the go is paramount nowadays, especially since heavy use — looking at you Facebook, Snapchat, and Pokémon Go! — can kill your battery before day's end. When that happens, and there's no outlet in site, a battery pack will be your best friend. But which battery pack? Here are our favorites!

Get smart: Apple Smart Battery Case

Staff Favorite $129 at Amazon

Credit card-sized: TravelCard 1500mAh

You can grab a TravelCard that's made specifically for the iPhone with a built-in Lightning cable. 1500mAh won't give you a full charge, but it should help you make it to the end of the day, which is really all you can expect out of a credit card-sized battery pack.

$29 at TravelCard

High capacity: RAVPower Ace 22000mAh

If you think you'll need to charge up your iPhone more than once before you see an outlet again, then this high-capacity power bank is what you want. It'll charge your iPhone up 5 times at least, and it's relatively compact, so it shouldn't take up much real estate in your bag.

$42 at Amazon

Candy bar-sized: Anker Astro E1 6700mAh

If you're looking for an exceptionally portable charging option, the Anker Astro E1 is perfect. It's roughly the size of a chocolate bar and should charge your iPhone at least once, if not one and a half times. Comes in four colors.

$24 at Amazon

Budget pick: Aibocn 10000mAh

10000mAh should charge your iPhone a couple times, and this power bank comes with a built-in flashlight, making it perfect for camping or in case of an emergency. You can charge two devices simultaneously at normal speeds.

$11 at Amazon

Fast charging: Anker PowerCore+ 26800mAh PD charger

If you want to fast charge your newer iPhones, you'll need a power bank that offers USB-C Power Delivery like this one. It'll charge your iPhone at least six times with a USB-C to Lightning cable, and you'll be able to charge the iPhone 8 and later as quickly as possible.

$130 at Amazon

Pocket-size: Jackery Bolt 6000mAh

Jackery's Bolt is a slim option with a built-in Lightning cable, so there's no need for you to carry one around with you. With 6000mAh, it should be able to juice up your iPhone at least once. It comes in gray and vibrant orange..

$30 at Amazon

Built-in A/C: Ventev Powercell 6000mAh

Ventev's Powercell charger has a built-in A/C connector, as well as a built-in Lightning cable, so it's everything you need for charging up your iPhone and for charging the power bank itself, all in a portable package topped with LED lights.

$42 at Amazon

Solar power: Be-charming 24000mAh solar charger

This high-capacity power bank has a solar panel, so once its 24000mAh battery is depleted, you can leave it out in the sun to charge, making it perfect to take on camping trips and long hikes.

$29 at Amazon

Slim and lightweight: Kanex External Battery Pack 8000mAh

The Kanex External Battery Pack is a slim and lightweight slab that packs in 8000mAh of power. You charge it up with a separate micro USB cable. But when you need to charge up your phone, just pull out the built-in micro USB cable and stick it into the included Lightning adapter, then just pop it into your iPhone. No need to bring separate cables along, and it's dual-purpose for micro USB devices too.

$24 at Amazon

A popular and trusted option: Anker PowerCore 10000mAh

Anker is one of our favorite brands, and the PowerCore 10000mAh packs in a good amount of power in a small and compact form factor. It's enough for three and a half iPhone charges, and it even features fast charging capabilities.

$32 at Amazon

All-in-one solution: myCharge HubMax 10050mAh Portable Charger

The MyCharge HubMax is a fantastic solution when you use multiple devices. It holds 10050mAh of charge and has built-in micro USB and Lightning cables. There is also a USB-A port for additional devices. The HubMax also has its own folding wall outlet plug, so you can plug it in directly.

$89 at Amazon

A portable power bank is the best way to make sure your iPhone keeps going until the end of the day or even a couple days if you go with the right one. The Ventev Powercell is my favorite charger, with its built-in Lightning cable and A/C connection — it's one of the most convenient options on this list, along with the MyCharge HubMax.

However, we can't get enough of the Apple Smart Battery Case. It really fits like a glove on your iPhone XS or XS Max, and the integrated battery status with iOS lets you know exactly how much juice you have left,and when you should get to an outlet.

I also personally like the Kanex External Battery, because it's slim and lightweight enough to fit into a purse, and having a built-in micro USB cable with Lightning adapter means I can have some extra charge with me anytime, even without the Smart Battery Case.

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