1060 plus pen

Hey,

So I bought a 1060 plus a few days ago and I'm a bit confused with it's pen. The manual says that with a full charge I can use it for 350 hours. I charged it for a whole night and on the first day it was fine. A few days later (today) it just doesn't respond to my tablet. I plugged it in my laptop and it started charging and could communicate with the tablet too. How much time should I charge this thing? Is it normal that I have to charge it after 4 or 5 days?