"Classic" changes its date

[grizzley]

I tried to look through the posts to see if someone has had a similar issue but could not find it so I am posing it here - sorry if I overlooked it.

I have two "Classic" 200 charging form different components of my RE system (wind and solar).  They work fine but there is one annoyance, those beasties keep resting their dates.  Usually they just change the year but it is enough to cause a headache if I missed it before I join the logs from previous downloads.  If I see it in time the sequence is fine but one line will read
6/10/00
6/10/00
6/9/00
6/9/00
6/8/15
6/7/15
6/6/15
6/5/15
Sometimes both will do this on the same date but usually one does it this month and the other a month or two later.  Anyone have any idea as to why and if and what I can do about it.  As I said they seem to work fine but this date thing is annoying.

[Resthome]

I tried to look through the posts to see if someone has had a similar issue but could not find it so I am posing it here - sorry if I overlooked it.

I have two "Classic" 200 charging form different components of my RE system (wind and solar).  They work fine but there is one annoyance, those beasties keep resting their dates.  Usually they just change the year but it is enough to cause a headache if I missed it before I join the logs from previous downloads.  If I see it in time the sequence is fine but one line will read
6/10/00
6/10/00
6/9/00
6/9/00
6/8/15
6/7/15
6/6/15
6/5/15
Sometimes both will do this on the same date but usually one does it this month and the other a month or two later.  Anyone have any idea as to why and if and what I can do about it.  As I said they seem to work fine but this date thing is annoying.

Assume you have the MNGP. there is a battery that keep the clock alive. In the past the little paper that they put in between the battery and the metal hold would leave a residue on the metal prongs of the holder. Also might want to see if the battery voltage is still good. Just a wild guess.

Where are you reading these dates from the log menus on the MNGP?

[grizzley]

Those dates are from the downloaded log on my computer. 

I had forgotten about those batteries.  I installed the controllers in 2012 so I should probably check, clean and replace if necessary.