My MacBook turns off when not on charge

It looks like you have two problems here a bad battery and the charging logic on the logic board has problems too.

Did you have a liquid spill at some point or sit you system down on a wet surface?

Sadly this system is going to take a bit of work to get going again. First you need to fix the charging logic on the logic board. You likely have corrosion damage and this will take either a good skilled person with micro-soldering skills and access to the needed parts. This is beyond a simple DIY project. The logic board will need to be cleaned of what was spilled and the corrosion damage fixed and the replacement of the damaged parts.

You could just replace your bad board with a working board you’ll need still need to replace the battery (you want to do this the second task).

• Here’s the guide to replace the logic board, it also has a listing of the logic boards: Reemplazo de la placa lógica del MacBook Pro 13" Retina Display Early 2015
• Here’s the guide for replacing the battery and the needed parts: Reemplazo de la batería de MacBook Pro 13" con Pantalla de Retina Principios de 2015

The bottom line its going to cost you between $650 -900 depending on the logic board you go with. That was an expensive spill ;-{