Coffee spill: Fully functional but shuts down when unplugged

First I’m not sure why you think its not worth it! Five year old cars still have a lot of life in them, why wouldn’t a laptop? I could see you out growing what it can do, I can also see the pangs of all of the new wiz-bang features of the newer models also pulling at you. But, only you know what your needs are. Your system still has more to offer!

So looking at CoconutBattery I see the charger is not charging your battery. So we knew you do have a logic board issue. Are you up to fixing your own system? Review this guide MacBook Pro 13" Retina Display Mid 2014の基板の交換 as well as MacBook Pro 13" Retina Display Mid 2014 の出入力ボードの交換. What we need to do is look a bit deeper for all of the spilled coffee and clean it up. You’ll want some distilled water and 85% or better isopropyl alcohol and some cotton swabs. Use the distilled water to wipe the areas you see and then go over them again with the alcohol. Take some pics of anything that looks off and post them here for us to see. Depending on what we find we might be able to get you going, at worse you may need a new logic board.