Battery draining quickly - doorbell

Installed new doorbell in late November. Battery lasted around 6 weeks. Recharged fully and now it's down 75% in 5 days. Before that charge I removed motion alert, it no longer records and the weather has been warmer since before the New Year, very balmy. So what's going on? WiFi signal is very strong. Hardwire power is not an option. Unless it's fixable the whole kit is being returned as unfit for purpose.