viperman224 18 Junior Poster

I've charged my thinkpad for a few hours it says i have a full battery. After a few minutes the battery goes to 96% then 93% but all the while the hours left get higher. when it's fully charged it says it will last for 2 hours 15mins to 2 and a half hours. when it goes to 90% it says it has 3 or more hours on the battery. can someone help me out? by the way it's an ibm thinkpad t22 PIII 900mhz with speed step tech.