Flat batteries. They’re the bane of a gadget-loving geek’s life. As phones get more powerful, with bigger screens, battery life is just not what it used to be.

Users of modern smartphones know the drill only too well: grab that bit of precious juice when you can, be it from your computer’s USB trickle-charge when you’re at your desk, or from a car cigarette-lighter charger while you’re driving around town.

While smartphone technology has advanced at an incredible rate in recent years — top-end handsets are more powerful than good desktop PCs of a decade ago — battery technology has limped along by comparison.

At some point, surely, someone smart will devise a battery that lasts for weeks on a single charge. Until then, there is a range of solutions available to consumers, from car chargers to (often expensive) spare batteries.

There is another solution: portable battery chargers. Lots of companies make them, including handset manufacturers themselves.

But one product that arrived in TechCentral’s offices recently, the MiniGorilla portable battery and charger from a company called PowerTraveller, has really caught our attention in recent days.

It’s ugly — brick-like, about the size of two decks of playing cards, with gorilla-like black and grey styling (hence the beastly name). But it has a solid, almost industrial design and, most importantly, comes with an impressive array of adapters.

You’ll be able to charge just about any phone ever made, from Nokias to Sony Ericssons. There is also a full range of USB adapters. Curiously missing, however, is an adapter for the iPhone.

The MiniGorilla, which weighs in at just 265g, should charge most modern netbooks, mobile phones and camcorders. In fact, anything that requires 19V or less of DC input should work.

We charged an HTC Desire via the 5V USB port built into the side of the MiniGorilla and it juiced the phone fully in about the same time it takes via regular mains power.

The device outputs power in 8,4V, 9,5V, 10,5V, 12V and 19V. You can switch between voltage levels by clicking on the device’s single front-facing button — simplicity itself.

The device even switches itself off when it has finished doing its job. We estimate you’ll get about four or five full cellphone charges out of the MiniGorilla. We didn’t test it with a netbook, though other reviewers report getting a couple of extra hours out of their machines.

The MiniGorilla, which will set you back about £100 before import duties and other taxes, recharges from mains in just less than six hours.

The only real downside of the MiniGorilla is you’ll have to remember to keep it charged. Two flat batteries are of no use to man or, er, beast. — Duncan McLeod, TechCentral