Hi Siddharth <This is the name I wanted to give my son, now he is 9yrs>,

How fast are your reading the RTC? I mean, within one second, how many times are you reading it?...3 times, 30 times, 300 times,...?

In some cases, it does effect the accuracy of the RTC. This was confirmed by DallasSemiconductors, way back, (I think) 6~7 years back. 8052.com might be having my posts of that time about this problem.

I had used their RTC iButton, and was reading it about more than 100 times a second. This gave a problem that: when the Machine is switched OFF, the clock was giving proper timings, but when it was turned ON, it used to run faster.

Later, they made the necessary changes, and I changed it as a rule(in software) to read the RTC 3~5 times in one second, NOT more than that.

And it has worked out pretty well for almost all the RTCs (DS1302/DS1307/PCF8583/PCF8563/DS12C887/Dallas:iButtonRTC,etc...just to name a few) that I have used over the years.