It's happened to all of us: The day is waning, you're on a critical call on your smart phone, there's not an electrical outlet in sight and the battery is dying.
Aargh! (And other less acceptable expletives.)
What to do?
Easy - reach into your pocket or briefcase and grab a battery-operated charger, plug in and keep talking. There's a surprisingly large selection of these contraptions on the market, for virtually every phone, Bluetooth earpiece or MP3 player.
With today's powerful - and power-hungry - smart phones, it makes a lot of sense to have one of these chargers close at hand. You may not need it often, but when you do, it'll pay for itself many times over.
We had a look at a few representative units.
Duracell
The charger batteries from Duracell vary only in capacity and size. The smaller pair, the Pocket USB Charger and the Instant USB Charger, each provide about 180 minutes of talk time on an iPhone 3G, BlackBerry Curve or Motorola RAZR V3 (as with any battery-powered device, your mileage may vary), and the Powerhouse (about the size of a deck of cards) will charge the iPhone completely and have some juice left over.
Regardless of capacity, each charger contains a lithium ion battery that is recharged via a USB connection to your computer. To charge your phone, plug the battery into its charging port and press the power button on the front. Duracell supplies a mini USB connector and says that for devices with specialized plugs such as iPhones, a USB cable with the device-specific connector should be used. Manufacturers' suggested prices run from $24.99 for the Pocket to $69.99 for the Powerhouse.
Scosche
If you spend a lot of time in vehicles or off the grid, the $29.99 (U.S.) Scosche Solar Powered Backup Battery and Charger provides an interesting twist. It's about the size and shape of a small smart phone, and one side is covered with a solar panel. It comes with a universal carabiner mount, for clipping to backpacks, and a mount cradle with suction cups so you can stick the unit on a car windshield or even an airplane window. I charged it by leaving it on the windowsill in my office. It takes a while (18 hours from zero to full), but if you're pressed for time you can plug it into a computer USB port and juice it up in a couple of hours.
It comes with a micro-USB cable, but as with the Duracells, you can use a USB-to-specialized connector cable to charge your iPhone. Scosche also offers a compact $19.99 iPhone cable module that attaches to a keychain.
Callpod
Next up is the Callpod FuelTank Duo ($69.95). It's bigger than the others - like a paperback book - but it also packs a lot more power into its dual battery pods so it's great for prolonged use. It can charge two devices at a time, and holds sufficient power to charge each multiple times. We proved the point on a long road trip, keeping a Palm Treo topped up for several days without ever recharging the Duo.
To fill the "tank" all you need to do is plug the Duo into an electrical outlet using the supplied AC adapter. You can view charging status with the push of a button. The Duo comes with mini USB, micro USB and iPhone/iPod device adapters, plus a voucher for another adapter of your choice - and there are more than 3,000 to choose from, for everything from cameras to your GPS device. For less demanding, single-device applications, the company also offers the $49.95 FuelTank Uno.
Ecosol
Finally, we have the Powerstick, from Ottawa-based Ecosol. The most compact of the batch, it looks like a giant USB data key - and several models do contain data storage as well as their lithium polymer battery. We tested a baby blue one (yes, you can get them in colours as well as basic black) with 8 GB of memory.
Regardless of colour and memory, each Powerstick comes with nine adapters that run the gamut of device connectors from Palm Treo to Apple iPhone to mini and micro USB. It charges, as one would expect, from a computer USB port, and an LCD meter on the side shows you how charging is progressing, and how much capacity is left when the Powerstick is charging a device. It takes about an hour to top up the Powerstick, and it took about the same amount of time for it to deliver almost a full charge to a BlackBerry Curve.
To charge a device, you simply plug the appropriate adapter into the end of the stick, attach the device, then push a button. If you're on a call, you then just keep talking - I found it easy to hold both phone and Powerstick while the device charged.
The Classic Powerstick (without memory) lists for $49.50 (U.S.). With memory, prices range from $74.50 for a 2-GB model to $94.50 for the 8-GB.