Also, my Galaxy Note 1 battery blew up on me because I used a cheap charger. I simply took it out, disposed of it at a city waste center, and put in a new battery for 15€. Try this with a "closed" phone. Either you can do it yourself, which requires at minimum 3h time + specialized equipment (e.g. regulated hot air gun), or pay 100€+ to a service center.

Thanks but no thanks to fixed batteries.