My phone's battery has a problem and I need to replace it. I have a lot of important data in my phone and would like to whether changing the battery erases the data on the device.
No,changing battery doesn't erase phone data.The data won't be erased. Just switch it off before you remove the battery and insert a replacement battery.
As per GSMarena, Samsung Galaxy Note 4 has Removable Li-Ion 3220 mAh battery.
So, it doesn't affect your device anyhow if you change your battery to a new one.
Removable battery are easy to change. You can buy one from any Samsung Authorised store nearby. However, before going to remove battery off the device, make sure to turn off your device to prevent data loss, unwanted changes, irregularities or misbehaviour of device.
For more read user's comment on xda-developer's forum: Is it bad for the phone to pull out battery before shut-down?
Replacing the battery does not typically erase data on the phone. What phone are we talking about? If it has a removable battery, it should be very easy to swap out and swap in batteries.
Having said that, always power down the phone first, before you take the battery off.
Some phone after removing battery will reset the system time