If you are screwing down the aspire and you don't feel any resistance before it sits flush on the battery, more than likely the contact on the new head is not reaching the contact on the battery. I am not sure exactly what kind of power source you are using, so I am guesstimating here, but you can try and use a small flat head screwdriver to pry up (gently and slightly) the 510 connection on your battery. Below is a video of how it is done. I hope this helps.