jailbreak and battery problem

[kreck]

I jailbroke my iphone and now when i charge it appear its fuly charged no problem yet but when i turn it off and back on it says i have less then 20% battery left. and then after about 2 turn offs it doesnt turn back on until i plug it in the computer wait for a while and then try plugged to the computer and it turns on saing i have less then 20% battery left when i have 100%... i dont know why i tried restoring but every time i jail break it same thing happens can anyone help?