My battery is Losing charge quickly. How best to replace?

Sarahgreen Registered Users Posts: 1
Apprentice Seeker
edited January 24 in TomTom Sports
My battery is losing charge in under an hour despite long charging times. Have looked at settings to help which has not. Watch is 5 years old approx. Think new battery is best option. Can you advise how best to identify watch type and correct battery for replacement please?