While Apple has made some advances in iPhone battery life, most heavy smartphone users of their smartphone will run into that Low Battery warning at some stage of the day. Despite the latest phones having made significant leaps forward, the iPhone X and XS generations are still not able to last a full day. 

According to Apple, the 2,716mAh cell on the iPhone X will get you 21 hours of talk time, 12 hours browsing the Internet, 13 hours watching video, or 60 hours listening to audio – although not all at the same time, of course!

The iPhone XS battery capacity is slightly smaller than the X, at 2658mAh. While the XS’s A12 Bionic SoC chip is more efficient, the smaller cell means battery life is not significantly improved. The XS Max does at least bump this up to 3174mAh, but that still isn't enough for most people!

There aren't a huge amount of Apple-certified cases out there, but you can trust the brands in this round-up to produce a quality product. Other than that you can, of course, buy a no-power protective case - see Macworld's round-up of the best iPhone X cases. And don't forget Macworld's great tips on improving iPhone battery life.

Although some claim much higher capacities we found most of these maxed out at a full recharge, so the 3,200mAh case did nearly as well as the 5,000mAh cases tested here. Even the Apple battery case (with its apparently meagre 1,369mAh capacity) got us a 90 per cent recharge.

Remember most of these are not Apple certified. Though we tested the products reviewed here and they mostly worked fine, Apple recommends using only accessories that it has certified (MFI) and that come with the "Made for iPod/iPhone/iPad" logo.

Apple Smart Battery Case for iPhone XS and XS Max

Apple Smart Battery Case for iPhone XS, XS Max and XR

Compatible with: iPhone X, iPhone XS, iPhone XS Max, iPhone XR.

A good few months after the launch of the iPhone XS and XS Max, Apple finally released its own battery case for the new iPhones.

Luckily for owners of the older iPhone X, it fits that model, too - despite the newer iPhone featuring a slightly larger camera at the back.

There are three models: one for the iPhone XS, one for the XS Max, and another for the XR. The XS case fits the iPhone X. Each is available in either Black or White.

We liked the previous versions of the Apple Smart Battery Case not for its looks (it sports something of a humped back) but its intelligent charging routine. Once encased your phone will use up the case's battery charge first, and then fall back to its own - so your iPhone should always be charged.

You don't need to push a button to get to the charge; it's all done automatically. It has the lowest claimed battery capoacity of any of the cases tested here, but that 1,369mAh got a phone at 1% up to 91%, which is resepcatble - and not far off how some of the claimed 5,000mAh cases performed.

There aren't any LED battery indicators on the case (except a charging light inside) as the battery status of both iPhone and Case are displayed on the iPhone Lock screen and in the Notification Centre.

The case offers robust protection from knocks and drops, and it's easy to slip the phone in and out. You can charge the phone and case at the same time; and the case (like the iPhone) is Qi-compatible for wireless charging.

Get over the looks, it's the extra battery power and protection you're after. It's only real downside is the eye-watering £129/$129 price tag, which is certainly steep compared to many of the Chinese cases tested here. But it's the only one that fully Apple Certified if that level of safety is important to you.

If you're going to use it as your main iPhone case, consider investing in the Apple Smart Battery Case. If you want something cheaper or just for emergencies and long-haul travel, then keep reading for less expensive third-party options. 

Read Macworld's full Apple Smart Battery Case review.

Available directly from Apple or on Amazon.

Kilponene Battery Case for iPhone X/XS

Kilponene Battery Case for iPhone X/XS

Compatible with: iPhone X, iPhone XS, with a version for the XS Max.

The Kilponene Battery Case for iPhone X/XS is a one-piece protective case rated at a whopping 6,500mAh (24Wh).

The significant difference to the Apple battery case is the price-tag – where it costs about a fifth of the price. It works well and feels rugged enough for protection from drops and bashes, so there's not a lot to dissuade you from buying a battery case at this price - note that, at the time of writing, it isn't available in the US, sadly.

Unlike the Apple Smart Battery Case and the Newdery case (below) it doesn’t support wireless charging, but does use Lightning to power up.

In real-life testing, we got an iPhone X at 15% up to 100%, and then from 30% to 60%, so around a 115% recharge capacity - more than enough for most users’ needs.

Unlike the Apple case, the Kilponene requires you to push a button to initiate charging the phone from the case - think of it as a power bank that also protects your precious iPhone.

It features a Lightning connector, so no nasty MicroUSB cables, and this also means that you can use a Lightning headphone jack adapter if you don’t have wireless audio.

We tested the version for iPhone XS. At 148g, it’s about 50% heavier than the Apple Smart Case. At 1.7cm deep this case is very slightly larger than the Apple. There is also a 7,800mAh model for iPhone XS Max.

It also lacks the more comfortable flexible top for inserting and withdrawing the phone from the case, although it’s easy enough, and don't forget that low price tag!

You can charge both the phone and case at the same time. A button at the back next to the four LED indicator lights switches charging on and off.

Mophie Juice Pack Air for iPhone X

Mophie Juice Pack Air for iPhone X

Compatible with: iPhone X

Mophie leads the way when it comes to charging accessories. The Juice Pack Air cushion your battery life so you can use your iPhone X for a total of 30 hours. It has a 1720mAh battery that works with wireless charging too.

It comes with a micro USB cable that you can attach to a computer to charge both your phone and case. The Priority+ features uses pass-through charge to charge your iPhone first, and then the case. 

Aside from a lithe total weight of around 80g, it also has a lithe price of £29.95/US$29.95 right now, which is £70/$70 less than what it typically costs.

Head to Mophie or Amazon now to pick it up now.

The case comes with a 2-year warranty.

Mophie Juice Pack Access for iPhone X/Xs

Mophie Juice Pack Access for iPhone X/Xs

Compatible with: iPhone X, iPhone XS

While we're looking at Mophie, it's also worth pointing out the bigger sibling to the Juice Pack Air, the Juice Pack Access. It offers a higher 2000mAh of power which also makes it slightly more expensive at £49.95/US$49.95.

The Access maintains, well, access to the Lightning port so you can plug in your wired AirPods if you want to without disrupting the charging. 

Pick it up from Mophie or Amazon.

Runsy 5000mAh iPhone X Battery Case

Runsy 5000mAh iPhone X Battery Case

Compatible with: iPhone X, iPhone XS.

The Runsy battery case packs 5,000mAh of power and comes with a power switch that lets you turn the battery on and off as desired.

From a protection standpoint, it has a raised bezel to keep that iPhone X screen scuff and scratch-free. Plus a matte finish adds grip, which is a useful safeguard for unexpected drops.

There's a pull-out stand on the back so you can set your iPhone up in a landscape position on a table or desk.

At 154g, it's heavy and a little bulky, too. We prefer the Kilponene Battery Case as a little less bulky, but none beat the Apple Smart Battery Case for lightness.

You start a recharge by pushing the button underneath the large LED battery indicators. In testing, we got a lot of portable power for our money - with over 140% recharge. That's the highest recharge we got in all our iPhone X and XS battery case tests.

The Runsy battery case also supports Apple Lightning wired headphone listening, and can take a Lightning-to-headphone adapter.

It's not currently available in the US. In the UK, you can pick it up from Amazon for £26.99.

Newdery Wireless Battery Case for iPhone X/XS

Newdery Wireless Battery Case for iPhone X/XS

One not to buy

The Newdery Battery Case for iPhone X/XS looks like a real bargain.

It’s a one-piece protective case that offers not just a 6,000mAh (22.2Wh) battery but Qi wireless charging too. This means you can charge both phone and case using a wireless charger – ideal if you hate cables. Only the expensive Apple Smart Battery Case included wireless charging, so this is a much cheaper option.

But here comes the bad news: In real-life testing, the Newdery failed to work, and the power-on button feels flimsy and breakable.

The case weighs 159g, which is a fair bit heavier than the Apple battery case, and is 2.3cm at its thickest depth.

If you're looking for battery cases for other iPhone models, read our roundups of the best battery cases for iPhone 6/6s and 6/6s Plus, the best battery cases for iPhone and 7 Plus, and best battery cases for the iPhone 8). And now you can also find the best battery case for the iPhone 11.