RTC malfunctioning and not showing accurate data
i am using STM3210E Eval board which has STM32F103 uC i am trying to recorded some adc value over the period of long time but with the time. I am using RTC to achieve that so that even in case pf power loss the adc might not get measured but the time stays correct. As per my cell holder's size in the board i am using CR1220 button cell of 3V and have changed the jumper to give cell volatge to VBAT of uC but the values i am getting out of RTC is not correct. It does stays even if main supply is off but the value itself is not correct for example it's seconds goes upto 90 and then next min comes up but on measuring that 90 seconds is actually 60s only where few steps are missed to like after72 it's directly 80. I haven't checked for min,hr and more but even so the value is totally incorrect. i mean just look at below.

i mean how can the year go to 36 and date to 41 and hours 33!!!. i mean why is it like this what changes do i need to make to get it right
PS: i had programmed it 2 days ago to match it at that time it was showing correct at that moment but two days later it's just this

