Late fees in Minnesota

[Jason Nelson]

Hi I am Brand new to this. After a bad car accident I was forced to rent out the house that I have owned for 9 years.  I had given power of attorney to my sister, She is the one rented out the house. In the lease it is stated that that the late fee will be $25 a day. However the renters pointed out that 8% is maximum in MN. The renters have been there for over a year and are constantly  late between 14 days and up to 40 or 50 days late!!! I just assumed control of the property. My sister kept EXTREMELY DETAILED records. She has kept a total of all days late or missed. I will end up in small claims court with these people for various reasons. Can I still collect the back late payments? Todays date is 12-1-18 and they just paid me 500 for the month of November and still owe the other half. Because they have always been behind my sister has put them on a modified payment schedual where they pat every two weeks. What is the maximum I can charge and how do I calculate it? All I am finding online is the 8%. So what can I charge a day, and up to what amount? What about all the daily late fees for the past year?