This company makes two portable, lightweight battery packs with USB ports that charge just about any electronic device. The packs can be purchased or rented and come in two sizes: 6,000 milliamps (rent: $11/day; buy: $75) and 9,000 milliamps (rent: $14/day; buy: $100). The smaller of the packs will give an iPhone 5 at least 3 full charges before it needs recharge. Look for these guys at big events: tournaments, concerts, festivals and conventions.
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