A:AnswerOnly in a hot car from what I've noticed. I charged mine to full and didn't use it for weeks. When I finally needed to use it, I found it was at a full charge.
A:AnswerI'm not sure if you're asking how fast it will charge or how much it will charge? It charges at a standard rate, so you're not going to see fast charging speeds (for instance, if you are using the phone while this battery is plugged in charging, your battery level will remain constant). It depends on what phone you have, but for an iPhone it will charge it up by about 75-85%.
A:AnswerYou can reverse the USB cable and plug the USB portion into the USB portion of your computer and plug the universal portion into the universal port of the charger