USB Power To Go

Using USB as a power supply has been a theme on this blog since its inception back in 2006. At that time I coined the Universal Supply Bus term and have been watching the world adopting my idea. Well, not exactly my idea, as the idea of providing power together with signalling and data on a single universal connector has been invented long ago, and USB just made it widely popular. Designers went even to the extreme with products like AA cels charging directly from USB bus. What has helped recently was the EU and GSMA directives promoting the use of Micro USB as a standard communication and charging connectors.

Powering mobile devices is a problem that has not been solved yet, despite being central to the wildly growing market of power hungry mobile devices. Today's standard is a day of work on a charge. It is the minimum that can be offered. Nobody will buy a mobile phone that lasts half a day. And we all assume devices have to be charged overnight. Which is acceptable, as long, as there is power available overnight.

The problem is when something happens, and there is no overnight power. And usually when it happens you would like to use your mobile more intensively. Examples? Winter is coming to the northern hemisphere. Which means sudden weather changes, often resulting in closed airports. I happened to spend a number of nights at airport gates on several occasions. Before that you usually stand in a long line to a transfer desk. And standing in this line you see people desperately trying to make calls and send messages to rearrange their schedules, while their batteries just die. And added to the mess in inadequately small number of wall power sockets available at airports. They were planned for vacuum cleaners, not for charging passengers' iPhones.

Recently I have discovered a nice lineup of portable emergency backup batteries made by Energizer. They cleverly address the problem of depleted mobile power. Conceptually they are simple products. Rechargable batteries with USB sockets.  Charge them and then use as a power source to recharge your gadgets later on. They come in variety of sizes. I picked the XP4001 (pictured above), for two reasons. One - it has a decent 4000mAh capacity (an average mobile phone battery is 1500mAh, as a reference point, so this one would be able to fully charge a phone twice). And two - it has two outputs, able to charge two devices simultaneously.

I have to say I do like the concept a lot. And generally I like the product. Unfortunately it has one disadvantage, I have to warn my readers about. It comes with an own charger (yes, yet another charger!). Which would not be bad in itself, but the charger, although rated at 5V (1500mA), is not a USB charger. It uses a custom round pin instead, which I consider very stupid. Later when I have time I will try to make a small adapter cable and try one of a dozen of USB chargers I already have and use. This is not the case with the smaller ones (like the XP2000 model) - they have Mini (not Micro!) USB charging inputs. Energizer probably worried about the current required to charge the bigger battery (the supplied charger is rated at 1500mA, while a typical USB port is rated at only 500mA). But as USB charging standard has been adopted by all tablet vendors, many of them supply chargers able to deliver even 2000mA (like the iPad or the Samsung Galaxy USB chargers).