Chosen Solution
Dear everybody. My Macbook 12" dosn’t charge the battery any more but i need to retrieve the data before letting it repair (apple swaped the usb-board and now wants to exchange the logic board). i then connected the logic board directly with a laboratory power supply and supplied it with 7.55 volts (that’s what it is written on the battery). The computer seems to start up, but ends with the sign, that i need to charge the battery first. Does anybody have an idea, how to get the Macbook running for one last time? How hight would you go with the voltage? Or would it be possible to charge the battery with just the + and - contacts?
See if you can boot it up in Target mode and move your user folder to another hard drive. Here’s how: https://support.apple.com/en-us/HT204360
If you get a working board you should be able to charge the battery and run it off the battery. Not sure if apple will want to let you do this though
