Even if the Upp itself was lighter, the limited access to refills is a problem, with huge swathes of the UK and US without any locations. As much as I would love to advocate a potentially environmentally sound solution, in purely practical terms it simply isn't any match for buying a smaller, lighter, battery-powered charger and stocking up on batteries that can be bought anywhere. Just make sure you buy rechargeable batteries and recycle them.
If the Upp charged your device many times, of course, the size and availability of cartridges would be less of an issue. Sadly, at this early stage of the technology that isn't yet the case.
How many charges do you get?
Upp says one cartridge charges a phone five times. That means one cartridge should last around five days of normal phone use. I tested that by charging a selection of phones, all of which were completely dead to start with. I plugged them in one after the other, and found that I couldn't charge any more than three phones from one cartridge.
The first cartridge charged an, an and a before it was empty. The second cartridge charged a and a before it was exhausted.
Only two or three charges out of a single cartridge costing £10 or $17 is pretty disappointing. And it also means you have to stock up on lots of expensive, heavy cartridges, or make more trips to exchange them.
That said, you can squeeze a bit more juice out of a cartridge using the best thing about the Upp: the very clever app that comes with it.
The Upp app is by far the best thing about it -- at this early stage in fuel-cell technology, anyway -- and I'd happily use the app on my phone even without the Upp charger.
The Upp app, which is available for iPhone and Android, gives you fine control over the charging process. You can plug the charger into any phone and start charging, or install the app on the phone in question to see how much hydrogen is left in the cartridge and how much charge is in the battery. It also tells you how much time you have left to call people, play music, browse the Web or watch videos.
You can set the app to charge the phone to any percentage level you want -- so if you're running short on hydrogen or time you could opt to just top up the battery slightly instead of fully charging it.
As it approaches the specified level, the app slows the process so as not to waste hydrogen on keeping the phone topped off. This saves the small amount of energy constantly expended on running apps in the background, or keeping the Wi-Fi on.
The charger knows when the phone is fully charged and stops charging when the battery is full -- especially useful if, like most of us, you leave your phone charging overnight.
Fuel-cell technology is something to keep an eye on: it's efficient, it's green, and it may be the future. But at £150 for the charger, £35 for a cartridge and another £10 for every few charges, the Upp charger is simply too expensive -- and too heavy -- to compete with chargers that run on cheap, easy-to-find, lightweight batteries. The one positive is the excellent app.