Best back up charger for iPad 3
I'm looking into booster batteries to give my 30 pin connector/Spring 2012 iPad 3 extra hours when I'm in the field. I have looked at Zagg, HyperJuice (which are expensive) and others, but have read varying reviews. And the prices are all over the place. So I'm curious if forum members can advise:
1) What are the best back up battery charger/s?
2) I may need to use the iPad continuously for up to 12 hours or more. If I hook up a booster will it power a low iPad immediately so that I can continue to use it? Or does it take so long to recharge an iPad that a booster battery is not a solution for continuous use.
3) Is it better to get a higher mAh level for a faster charge?
4) Does giving your iPad a boost charge have any negative effect on your iPad?
Ted in Los Angeles