I trusted Apple and when my battery was not charging, I sent it to Apple Singapore last month. Was told diagnotics is free and will replace the battery if it is not logic board, if it is, will give quote and ask if I wish to repair. I also informed that I will not want to replace the battery nor replace the logic board if the logic board is not functioning well.
Next day, I was informed my Macair 11inch was ready for collection. Was relieved it was not the logic board. Should heed the warning sign when the technician could not power on as the battery was dead and had to use the adapter to power on. When queried, was told it was because they never charge to full. Thus, brought it back to find that battery was draining at 30% a day even when shut down. Alarmed, brought it back to Apple. Service staff upgraded the IOS and said if it’s not software, it will be the logic board and $S700 to replace. After installing the new upgrade, I asked the service staff to shut off after full charge and on again about 15minutes later to see if battery drains. When power on again, the meter was at 98%. Service staff seen it, did not comment, so, I was stupid to think as before that it was normal. I trusted Apple too much then, and brought it home again with the same problem.
Third time (my machine is still at Apple now), was told it’s the logic board that needs replaced. I was frustrated and angry and argued with the service staff who called to tell me the problem. I told him why would I replace a battery on a bad logic board or replace the logic board if the value of the early 2014 Macair is only worth less than $700. I paid S$188 for the battery. I said I reject the battery and wanted them to put in an old battery and want a refund. I got !#^&@@ off when he said that I sent in the machine because of battery and not logic board, two different issues. My Macair was working fine with the old battery on adapter. I am back to square one after all the inconviences of trying to book slots online on days I do not have busy schedules, contacting, going to town finding expensive parking spaces etc. and still have to use adapter. New battery suppose to be on standby as and when I need it.
My case is reverse and worst than yours, new battery on bad logic board. If they had told me logic board initially, definitely, there will be no battery replacement. I Won’t be surprised if after paying for new logic board, they say it’s other hardware problem.