I bought 2 of these on vacation. The first one leaked when I lied it down to charge it. I thought it must be defective so I ordered another. A few days later I charged the second one and that leaked too. The 3rd one also leaks. They are fine when standing but when I lie them down to charge they have to be almost empty or all the juice leaks out. I can't put them in my pocket because if they aren't completely vertical they leak. Anyone know what the problem might be?