I can't tell for the moment, I bought it this morning! But now it says 97% and I ended up charging around 11:30 when I posted.
Anyway, my S0 was dying. For example if I use it one day, I pick it up from the charger at 7-8 a.m., use it until 2 p.m. and then do a running workout (30 to 60 minutes) using the HRM, it dies around 3-4-5-6 p.m. so I have to charge it after running if I want to go later to the gym or do any other activity.
I hope this new one works better from here in advance
My S0 has been rocking from the day it was launched in Spain. I think it was in June 2015 so it has almost three years, used everyday and charged every night. The battery has suffered and has some degradation nowadays. So maybe it's not possible to compare in my case

I hope the new one last more and doesn't need any extra charge at mid-day
Thanks!
ISO