Plugable Technologies USB Data Blocker, Protect Against Juice Jacking at Public USB Ports, Defend Unwanted Data Transfers and Hijacking, Charging Safely, Fast 1A Charge-Only Adapter for Android, Apple iOS Devices

Plugable USB-MC1
The Plugable USB-MC1 adapter enables you to turn any USB data port in to a charge-only port. This can be advantageous as some devices charge too slowly or do not charge when connected to a USB data port. It also serves to protect your device and its data from hackers and viruses. The MC1 is smaller than a pack of chewing gum and will easily fit in your pocket. Perfect for on the go charging at airports, coffee shops, libraries, and more.

Battery charging over USB has become a standard practice but the actual charging behavior of different devices is often unpredictable and sometimes disappointing. Read below for more background information and if this is the right adapter for you.

USB Charging Information - How it Works
Most devices can't or won't charge from normal USB ports and powered hubs if the computer is turned off or not connected. That includes most Android, iOS, and Windows Mobile devices. The phone or tablet must negotiate how much power to pull, to do so by the original USB specification, devices are supposed to only draw 100mA at first and then they can then negotiate up to 500mA. This negotiation requires a PC that's attached and on. Unfortunately even at 500mA, charging most devices will take a very long time to charge.

For example, the iPhone and most other phones will charge on a standard port this way, but they can also charge faster (up to 1A) if the USB port sends a special, non-standard signal to say "I'm an Apple 1A charger". The Plugable MC1 adapter simulates that Apple 1A signal, turning any powered USB port with at least 1A power available into a charging port. Even though it's not standard, it's how Apple pioneered faster charging, and fortunately, nearly all phones and tablets on the market today recognize this signal as it has become the unofficial standard for USB charging.

For larger devices such as tablets like the iPad, this adapter is even more important because their batteries are larger and charging at 500mA would be too slow.