Why is my new computer battery not charging fully?

i got a new battery for my Acer computer. the instructions that came with the battery say that it’s hard for a computer to charge a brand new battery, so to re-set the charging cycle, you may have to remove the battery and reinstall it.

the battery has been charging for the last day and a half, (since Friday night and it’s now Sunday morning). when i checked it just now, and when i checked it yesterday morning, the amount of battery life left is pretty similar, so in other words it has not changed much. it says now “59% charged – one hour left.” it said “61% charged” yesterday morning so i am wondering what’s wrong. the instructions say to charge fully the first time so i don’t want to start using until it’s 100% charged. i have removed the battery about 4 times in the last 24 hours, as per instructions.