Chosen Solution
After a faulty USB cable fried my logic board, I needed a replacement. I got a used and tested one from iFixit. After replacing the logic board, the computer would only work from a charger, the battery was not recognized (the icon disappeared from the toolbar on the top as well.) I purchased an aftermarket battery from iFixit, but I have the same issue. After some more research I did an SMC reset and and NVRAM reset and checked with coconutBattery as well. When the battery is disconnected or when the old battery is connected, I can get the battery status icon back on the toolbar, but it shows 0% and coconutBattery shows nothing. When I connect the new battery, the battery icon disappears from the toolbar as soon as I try to put it back there. The whole logic board has just been replaced so I am suspecting a faulty replacement battery. Any ideas?
Sometimes it would be hard to diagnose. The worst scenario is a failure on your logic board, yeah your second motherboard replacement turns on, but are u sure that all IC involved on charge are working properly? It may be so hard to test, it needs the logic board diagram, scheme file to navigate on chips, equipment to test and replace damaged components by microsoldering.
When unplugging the old or replacement batteries did you use a metal tool to do so? If yes then the issue is most likely the data lines from the battery connector to the SMC to read battery information being shorted momentarily causing damage to the logic board by accident when disconnecting the battery with a metal prying tool. To fix this it requires microsoldering / board repairs so you’ll have to take it to a reputable board repair shop to do so. (replacing few components and at worst replacing the SMC, system management chip).
If the battery is still not being recognized after a logic board replacement I would first suggest you replace the DC in board because if the battery has no charge and the computer cannot supply power to the battery, obviously the computer will not recognize the battery. MacBook Pro Unibody 13" and 15" MagSafe DC-In Board
