The Mophie Juice Pack will be perfect for you. It is an iPad external battery and is compatible with most gadgets, but it is suitable particularly for the iPad. It charges your iPad quickly. It integrates innovative "high-output" technology and it delivers ultra-fast charging of your iPad. It has a 4000 mAh rechargeable lithium-ion polymer battery and 2.1A fast charging system for quick power. Its ultra compact design makes it simple to carry. It has a stylish soft touch exterior with metal side design and a six light "invisible" LED status indicator. The Mophie Juice Pack Powerstation for ipad charges at up to four times the current offered by traditional 500 mAh batteries. It can also switch between a 500 mAh charge, a 1A charge and a 2.1 A, which is simply great for an ipad.
The six LED status indicator lights, let you see the charging progress at a glance, then they disappear when not in use. These batteries can be used in the car, for home or anywhere. They are great for your iPad. The V39 USB Battery is an iPad external battery. It provides 10,600 mAh/39 Watt hour and can fully charge an iPad. It features two USB output ports, which are a hi-power port for fast tablet charging and a low-power port for Smartphones. It charges from a solar or a USB port. It gives an output of 5.5V, 900 mA and 5V, 2A. It requires an input of 5 to 12 V up to 2A. The maximum output power is 10 watts and the output capacity is 10,600 mAh. It requires a charge time of 10 hours for 8 Watts solar and 5 to 6 hours for 2A USB Port. The battery type is lithium polymer. It weighs around 10.5 Oz, which is, 300g. The dimensions are 104* 107*19mm.
You need to turn the battery on before you charge your ipad. You need to do this by holding the power button down for a few seconds. Many iPads charge at around 5-5.5V. The power requirement for a particular device is indicated on the device itself or on the charger, so you need to check that. If you do not find the correct adapter for your device, then you will have to make use of the manufacturer supplied USB cable. You need to research well on these types of batteries before you buy them, else you will end up buying the wrong kind of battery for your ipad.