battery question

Hyperjuice is a external battery that will supply "battery juice" for when your MacBook has depleted it's battery; for example, if your Macbook has 7 hours of battery in it, after 7 hours, when the battery has depleted, the external battery will kick in and give it an extra ** hours.

To an extent, your second statement is correct. The Macbook's battery has a certain amount of recharges that it can do, until it dies. If you recharge it every time it's at 80%, then it could affect the longevity of the battery. However, I wouldn't worry about this: if you know you're going to be going on a long train trip tomorrow and your battery is at 80%, charge it to 100%; if, however, you know that tomorrow, you won't use your Macbook as much, then leave it at 80% and charge it the day after. Basically: don't worry, use it and it'll live forever (metaphorically speaking).

 

No, it is not correct at all. You can recharge your battery anytime you want to. You don't need to drain it to a certain level first. This should answer most, if not all, of your battery questions:

Apple Notebook Battery FAQ​

This is not true. Read the link above for facts. Pay special attention to the section WHAT IS A CYCLE?

 

+1 to what GGJstudios wrote. This info is all over this site and of course at Apple. The store employee is confused with batteries from years ago, since he seems to be worried about the battery memory, which isn't an issue with these batteries. The second poster doesn't understand battery cycles.