If you’ve ever found yourself miles from anywhere with a dead cell phone battery, you’ll wish you’d invested in a portable power supply. Even the most modern of cell phone batteries struggle to keep up with the demands of modern smartphones’ touchscreens, GPS, cameras and array of apps.

A portable power supply is one of the most useful cell phone accessories you can buy, so before you get stuck without phone power while you’re out trail running, take a look at our roundup of the four best portable power supplies money can buy.

Mophie Powerstation PRO

If you’re looking for a rugged, dust proof and splash resistant portable power supply for your cell phone, one that has sufficient charge to keep your phone power topped-up on multiple occasions, the Mophie Powerstation Pro is a good place to start. I’ve been using this particular power supply for six months and it comes with me on almost every trip I make. With 6000mAh it’s powerful enough to almost charge an iPad, but has enough juice in it to top up your iPhone 3-4 times.

It has a USB port and micro-USB ports so you can connect it to just about anything.

[insert id=”297″]

PowerMonkey Extreme 12V

The PowerMonkey Extreme 12v is the daddy of portable power supply devices. Not only does it hold a colossal 9000 mAh, but it’s also solar powered – ideal for those multi-day treks where you don’t have access to mains phone power. Due to the solar panel, it’s not the lightest power supply we’ve reviewed, but you’re getting a lot of juice per oz.

And this shock resistant charging device is not only waterproof for up to 30 minutes, but is really easy and quick to recharge. And with it being 12V, you can charge those power hungry devices such as SLR camera batteries and DVD players as well as your cell phone and accessories.

[insert id=”299″]

Anker Astro Mini 3000mAh External Battery

Being the roughly the size of a tube of lipstick, the Anker Astro Mini is one of the smallest portable power supply devices on the market, but still packs a punch with 3000 mAh – enough to charge an iPhone.  It’s also fairly robust, being made of a tough aluminum outer shell. It’s perfect for one-day trips, trail running or hiking, where weight is important.

[insert id=”298″]

EasyAcc BP12000A Powerbank

Sometimes one portable power supply is not enough – especially if you’re out hiking with your kids, partner or friends, who all want to charge their respective cell phones. The beauty about the EasyAcc 12000A Powerbank is that it can simultaneously charge up to 4 USB driven devices. And with a battery capacity of 12000mAh, this portable power supply will keep everyone happy. However, you’ll need to allow plenty of time beforehand to make sure it’s fully charged.

[insert id=”300″]