Charging and Performance
The battery pack charges up relatively rapidly, reaching 75% charge in just over an hour. A full charge takes up to 6 hours, according to Enercell, but I found it topped off in closer to 3 hours. The charging time will probably depend on whether you plug into a “powered” USB port; without that boost, it probably will indeed take up to 6 hours. Most desktops have powered ports directly on the tower, while extensions or hubs – like on monitors and keyboards – are usually not powered. However, the power meter on the battery stays lit while it’s charging, making it easy to monitor.
There is little to no excess heat coming off the device; after charging my iPhone4, it was a little warm to the touch near the connector (on both the battery and my phone), but nothing more than would be expected from any electronics exchanging heavy amounts of energy. I had to squeeze around to find the warmth, so most uesrs probably won’t notice it at all – though again, I dont’ recommend leaving it in your pocket to charge, both for any possible heat discomfort and because of the size and potential to break the connector.
Performance-wise, I was impressed. It recharged an iPhone3G from fully dead to fully charged in about an hour, and it still had almost half a charge left in the battery. My iPhone4 didn’t fare quite as well, going from dead to about 3/4 charged, while emptying the entire load of the battery bank. Considering that a full charged is expected to last 6-10 hours of continuous use (and up to 300 hours of standby), it’s safe to say that Enercell provides an extra 6 hours of life – if not more. At $39.99, it’s worth a trip to Radio Shack if you need portable juice for your iDevice.