I bought an aftermarket battery for another Dell computer and it worked great at first. After a few months I pull the plug from the computer and it shuts off a few minutes later without warning.
Unless you buy original Dell brand (and make sure it's not old! New battery sits on shelf for a few years = crap) or from a reputable place like MugenPower, Best Buy, etc good luck. Good luck trying to claim "1 year warranty" from Chinese guy in Brooklyn from eBay too. I had one of these people get his wife to start anwering the phone "Beauty Salon" LOL