HP Pavilion G7 Shut down on SATURDAYS ONLY

[Mr 672A]

Ever since I replace the battery (the notebook told me via a message to replace it) on my wife 17 inch HP Pavilion G7 Notebook running Win 8.1 64 bit running a AMD AS 4500 APU with Radeon HP Graphics, 8.0g/b of ram AMD HD 7640 it shuts down ONLY ON SATURDAY after you start in and after 2 to 5 minutes ITS SHUTS DOWN WITH NO MESSAGE to tell you i'm shutting down and wont start again until you remove the battery and then leave it out for 2-5 minutes and refit it again and all is ok until next Saturday.
Now this has been going on for the last 2 months and yes we ask for a replacement battery from the ebay seller and the second one has done the same.
Now last week I told the wife not to start the notebook on Saturday so she did not use it but she started it on Sunday morning and it shut down after a few minutes the the first time and you cannot start it until you remove and refit the battery. So that was Sunday and said to the wife to test it to see if its a 7 day issue or a Saturday Issue so she started it today which is SATURDAY and it shut down again. Removed the Battery and left it out and refitted it in 5 minutes and its away again. So its not a 7 day thing it just Saturday problem
NOW!!! I fit the original battery that is worn out as the message tell me to replace it and the Notebook works perfectly and DOES NOT SHUT DOWN SATURDAY or and other day.
Some tell me that the computer does not like the ebay battery that have different MAH rating (New one is slight more capacity)

HELP whats going on!!