Water spill caused battery to stop functioning
Client spilled water on MacBook Air. Soon after the laptop would not function on battery-only power, even though it recognized it at as having 90% charge.
Very easy repair as long as you have the P5 Pentalobe and T5 Torx bits. It is a little maddening that Apple mixes these two bits up in the same laptop.
Just make sure you are using the proper bits on the proper screws. The base screws are also all slightly angled, so take that into consideration.