Alian battery

recently I purchased a battery for my smny ericson k800i.

While charging it gives message: "charging alien battery".

Although the timing is OK but what about this message?

I asked the shopkeeper from where I purchased about this message and he says its working what you want more.

Online search say that it could be a fake battery and might be it would drain faster after some time.

Any idea?

Yes sony ericsson phones have this feature that they can identify if a proper battery has been inserted or not. And if a fake battery is used it will show alien battery. But it doesn't matter as all the third party batteries are already fake so its ur luck that it holds a charge or not.