If keeping your smartphones, tablets and other gear running all day long is more important to you than keeping your backpack light, the latest addition to Limefuel's lineup of backup batteries — this 24,000mAh monstrosity — should be part of your daily kit.
Surprisingly though, it doesn't take up much space. It will certainly be heavier than those tiny batteries designed to give your phone enough life to place a call or two, but the Limefuel's added girth means it packs enough juice to full recharge an iPad twice over. That could keep you running for weeks.
It's also got a pair of 2.4A USB ports so multiple devices can share in the extra power at the same time. While not specified, this $US150 backup battery will take a long time to fully charge — definitely an overnight affair — but that's well worth the trouble for an emergency backup that just won't quit. [Limefuel]