Works well, but after 5 days the battery is empty

I have also bought the pen along with a Acer Switch 10 FHD. It works well, but after 5 days he had repeatedly misfires and finally he goes no longer. I used it a day maybe 1 hour and not kept in the vicinity of the tablet. I suspect that the battery is dead. Following the reports of the pin-like Dell (with similar battery-problems) I'm afraid that this is, unfortunately, standard and so you have to buy a new battery every week. So I'm thinking about the stylus to send back both the switch 10 as.

I would be interested how long does the battery for other use.