I received by Yoga 13 about a week ago. I was just wondering how do I replace my battery since it is sealed.

I notice that there is a warranty on the battery where Lenovo will replace it for you if you mail it to them, but it is only for one year.  

Would it be cheaper to extend my warranty or buy a battery and replace it myself?

You may want to have a look at the Yoga 13's Hardware Maintenance Manual to see the procedure for removing/replacing the main battery. Pages 33-38 show the required steps.

Please do note, though, that the battery is not considered a CRU (customer replacement unit). It simply means that if anything untoward were to happen while the machine was open, warranty repair might be refused. This is to be done strictly at your own risk if the machine is within the warranty period.

Only CRU part can be replaced by customers without voiding the warranty; however, it does not apply in this case which most of the ideapad especially Yoga 13 have a battery embedded inside.

lenovo sent me a replacement battery which i received today ( i am having issues that my old battery looses a charge when powered off )  i am going to replace the battery over the weekend and it it  doesnt fix it then i will send the whole unit into lenovo 

I have a similar issue inn which my battery has gone from lasting 5-6 hours on a full charge - even watching movies - to discharging from a full charge in a little over an hour. This happened abruptly. No slow degredation. It happened after I fell alseep on a planne and the battery ran down completely during my third movie on this fllight from one charge. It died completely and then I reharged it that evening in the hotel and noticed it the very next day when I used it and it died in about 90 minutes of only running MS Word to take notes! I'm wondering if letting it die the way I did caused this? I've always been told to let the battery die completely every once in a while anyway so I don't "train" it not to recieve a full charge. Any ideas?

We've just purchased a Lenovo Yoga and are not clear on these two points:

1. Does it shorten the battery's life to have the computer constantly charging? and if we happen to take it off the charge for a moment, to charge it again even if the battery is almost full?
2. is it better for the computer to shut it off whenever not being used?

Thanks in advance!