Now I must say I am very impressed by this item. I thought my only option for camping was a rechargeable power bank. Of course this gets very tricky when this needs charging as well and you are still needing to charge thinsgs. So I say we start to look for some sort of things like this, that will be helpful. So with this survival item, if you phones battery is going dead you do have the option to hook up the phone to this item, begin to crank and watch the charging icon come up. I was able to crank for a little over an hours and y batter jumped in power. I cannot tell you how long you would have to crank for a full battery but my guess is that you would give up.