I have been mining for 26 days now with the 3 mining rigs i built for 14500$.
So far i have earned 0.17404 BTC which equals to 1401$ at current bitcoin price (8051$).
To get the profit i have to take out the electricity costs which were: total farm takes 3200W of power * 24h * 26 days at 0.12$ per kwh = 239$
TOTAL profit in the last 26 days = 1162$
ROI with the 26 days = 8.01%
The ROI if the btc price stays the same and earning stay the same will be:
1162$ / 26 days = 44.69$ per day
14500$ for 3 rigs / 44.69$ profit per day = 324 days or 0.308% per day
When i first built the rigs the ROI was at around 200...250 days but because of the bitcoin price going down right now the ROI looks like to be around a year.
I am actually not too worried about ROI because i am quite sure bitcoin's price wont stay at 8000$ for the next year. Lets say if i mined for 3 more months and the bitcoin price jumped to 15000$ i would be 70% ROI. This could easily happen.
Thanks for reading :)