laptop dell battery problem

Hello guys
I have a problem with my laptop and i have no one to ask.
I have a DELL inspiron 1525 about 1year and 4 months now and he is causing me problems with the battery. i rarely use it on battery but when i do, it lasts approximatively 2h-2h15 with wireless, like... a month ago i did that... but now... he just crashed at 40-38% battery without a warning... just suddenly battery empty -> stand by. When i recharge it turned off, it goes up to 100% an then it last till 40-38%. Then, my laptop on, I try to charge it but it only charges at about 53% (i tried 3 times, empty battery, then recharge, laptop on and working) and then the sign for charging battery becomes the one showing me that is on AC power. Also, the LED that shows me when the battery charges, turns off. If i use it on battery from that 53% level... it lasts about 1h... like... a half from the initial time. I really cannot understand where is the problem. I am the only user... i cannot see where i went wrong with it.
In conclusion: if i recharge it turned off, it goes till 100% and the i used till 40% and crashes, suddenly battery empty signal;
if i recharge it turned on and using it, it goes till 53% and it tells me like... it is full and it doesnt want to recharge more. ..
Please, i could really use some help.

 

It's time for a new battery. It appears that yours won't fully charge, even though it says 100%. Also it appears the reading for what % of the battery remaining is not reading correctly. If it turns off at 40%, you can be sure that it was closer to 4% left and that's why the computer shut down.

 

It does sound like you need a new battery. One more quick test is that battery has a press to test feature on the bottom. If when you run the battery down to 40% and it shuts down flipthe laptop over and press the button, if you have one light blinking its time for a battery. If you have two or three you may have a power setting off.
control pannel----power settings------alarm slide the slider from %40 to %10