Amazon has a pretty decent deal on a 9,000mAh rugged and water resistant battery pack from Photive. It's on sale for $39.95 and it's normal price is around $119.95. Great power with Great protection- Water-tight ports and Impact resistant housing means serious protection. The Bolt can survive most adventurers demanding conditions. With a proven rating of IP-65 the Bolt can easily survive a drop in the mud, sand, dirt or water. Ultra high capacity keeps you powered up for days- packs a whopping 9000 mAh of power thatll keep most mobile devices charged to full capacity, many times over. The Photive Bolt is great for Campers, hikers, skiers, construction workers, and many other outdoor enthusiasts Premium Lithium-ion grade A cells ensure long lasting reliable power. High Speed Charging ports optimized for Tablets, Smartphones, and many other 5v mobile devices.