It's no secret that iPhone owners often struggle with battery life issues, and that iPhones are pretty easy to break. That's where battery cases come in, both protecting from bumps, knocks and scratches, and giving the power a boost.

We've tested lots of battery cases for iPhone, including the iPhone 6s, iPhone 7, iPhone 8, iPhone X and Plus models. Our sister site, Tech Advisor also has a dedicated round up of the best iPhone X battery cases.

If you've already got a case and would prefer a separate battery pack, check out our article on the best power banks for iPhone.

Otherwise read on for our pick of the best battery cases you can buy.

Runsy 5000mAh iPhone X Battery Case

Runsy 5000mAh iPhone X Battery Case

With the launch of the iPhone XS, XS Max and XR in September 2018, Apple has discontinued the original X, but that doesn't mean you still can't find battery cases for it.

The Runsy battery case for the iPhone X packs a powerful punch at 5,000mAh. Our colleagues at Tech Advisor featured it in the round up of the best iPhone X battery cases

On the Runsy case, you can turn the battery on and off depending on when you need it, and can leave the case on even when syncing. It supports both wired and wireless headphones.

The Runsy case is protective too with a rugged outer shell and a raised bezel to keep your iPhone X screen from getting scratched.

Ding Ding 3200mAh iPhone X Battery Case

Ding Ding 3200mAh iPhone X Battery Case

The Ding Ding iPhone X battery case may have a funny name, but it packs 3,200mAh of power, which is enough to add a full charge and then some. The case lets you attach a Lightning cable to charge both your phone and case at the same time – a useful feature to have.

There's a power button on the back too and an LED indicator. Simply tap the power button to know how much juice you have left. Hold the power button for 2 seconds to start charging and tap twice to stop charging. It's also designed to prevent your phone from overheating or short-circuiting.

If you do run into any issues, the company has a 100% money back guarantee and a two-year replacement warranty.

Apple iPhone 7 Smart Battery Case

Apple iPhone 7 Smart Battery Case

Following the initial scepticism about the design of the Smart Battery Case, it turns out it's a very well performing, useful accessory.

It looks a bit peculiar - it's a fairly standard silicone case that allows you to easily insert and remove the iPhone, but with an extra portion that bulges out from the case and houses the battery, which should give you up to 25 hours more power.

The one downside to having is that it costs £99. It's a high price no doubt, but it is very good, and will make your iPhone last the best part of 2 days.

Apple doesn't strictly sell a Smart Battery Case for iPhone 8, but this iPhone 7 model fits with no problems. There's also a version for the iPhone 6/6s, available for £99/$99 (see more details below). There's no Smart Battery Case for the iPhone 7 Plus or 8 Plus, though.

Apple iPhone 6s Smart Battery Case

Apple iPhone 6s Smart Battery Case

The Smart Battery Case is also available for the iPhone 6/6s.

What's interesting is that Apple has added an intelligent battery status that works with the case to show you how much charge you have left on the phone and case, and that information can be found on the iPhone lock screen and in the Notification Centre. It's also charged via Lightning cable and not Micro USB like many others in our roundup.

Mophie Juice Pack Air

Mophie Juice Pack Air

This case, which also allows wireless charging, is available for the iPhone 7 or iPhone 7 Plus (which works with the iPhone 8 and iPhone 8 Plus respectively). In the US it's available for around $49 for the iPhone 7 Plus.

Battery cases are a bit of a mixed bag - they provide extra power and protection for your iPhone, but they’re often rather large and chunky and can spoil the look of the iPhone's slimline design. However, Mophie's Juice Pack Air is slimmer and more elegant than many rival cases, while still providing a really big boost to battery life when you need it. 

However, Mophie's Juice Pack Air is slimmer and more elegant than many rival cases, while still providing a really big boost to battery life when you need it. 

It looks very much like a conventional protective case, with a tough rubber housing that can withstand bumps and drops. We also like the raised bezel around the edge of the screen, which helps to protect it when you place it face down on a flat surface.

The case does obscure the ports on the bottom edge of the phone, but Mophie includes a headphone adaptor and micro-USB cable so that you can still charge the phone and listen to music without having to remove the case.

And, despite the slimline design, the Juice Pack Air manages to provide a battery capacity of 2,525mAh, which is enough to completely recharge your iPhone.

Anker PowerCore 2200mAh Battery Case for iPhone 7

Anker PowerCore 2200mAh Battery Case for iPhone 7

This is a decent, cheaper alternative to Apple's official cases. It fits the iPhone 6, 6s and iPhone 7.

The battery is enough to add up to 11 hours of talk time, 7 hours of video or 9 hours of audio. It also doesn't cover the Lightning port so if you have an iPhone you can still plug headphones in.

The build quality isn't as good as Apple, but at about £60 cheaper you may not mind.

Moshi Ionsuit battery pack and case

Moshi Ionsuit battery pack and case

Moshi has made a name for itself in the accessories business, and this clever case helps that.

It is a slide on battery pack but you can use the case on its own when not in use. If you want the quick convenience of a battery case, but the option to take the battery pack on and off while still having protection, this is the one.

It's for the iPhone 7 or iPhone 8.

Savfy Battery Case

Savfy Battery Case

Although around the same weight as the Mophies, because it’s slimmer the Savfy Battery Case feels lighter and more portable. Its 3,200mAh battery capacity is impressive, and will easily give you a full recharge, with some left over for later.

It’s a two-part design, with a solid-looking plastic bumper and hard-shell backplate, which features a handy LED battery-level indicator. You fit the iPhone into the backplate, then snap the bumper over.

It comes with a charging cable and pass-through jack so that angled headphone jacks will fit.