i have the same problem except that my old battery was recognized and charged by the computer, but when i install the new battery it was not recognized, as someone told us some of these batteries come from china, and posibly have traveled a month or more, so they are depleted. What i did was simple, first check if there was some volts on it, and the result was not even cero volts, so everyone question was how to CHARGE YOUR BATT OUT OF YOUR MAC knowing that the computer wont even charge it. EASY>> throw it some VOLTS inside!!! so what i did was to connect the battery directly to a 6 volts 1200 mhA and leave it there 30 minutes, at the end i test again Volts and now it shows it has 6 volts, i leave it other 30 more minutes, then put it back on the MAC . and VOILA!!! IT WORKS! as soon as i connect the battery the computer turn on automatically, Now it has been recognized so the computer charged it and on my first use it work for 4 hours and has left 30%