You have a S2000, not a S+.
Personally I'd replace the battery with a battery holder and standard coin cell. That way there's no soldering involved the next time it needs to be replaced. I use a CR2354 holder and battery on mine, they last for years and years.
The rechargeable battery should be removed. It's not required for home use and those things have destroyed lots and lots of S2000 MPUs when they decide to leak. If you have a 50X series MPU board you can just remove it and throw it away. If it's a 1270 there's another component that needs to be removed along with the battery.