Hi dear ,tks for your message , 1.It doesn't matter whether the battery has a protection circuit or not, the most important thing is that the size of the battery can fit the battery holder. 2.It can fit the N300 case? 3. I2C address can not changeable? 4.There are many Raspberry Pi fans exchange experiences on our official website, you are welcome to join us https://geekworm.com/community/forum