Final answer.
I found a support email for the manufacturer and asked to explain what is RATED CHARGE POWER and MAX PV ARRAY POWER and how do I use those numbers. I was surpriesed when just a few hours later I got the answer from:
BEIJING EPSOLAR TECHNOLOGY CO., LTD.
BLDG# 18, CO.PARK, NO.8 HEYING ROAD, CHANGPING DISTRICT, BEIJING, CHINA. 102200
Tel.86-10-82894112 / 82894962 Ext.6056 Fax. 86-10-82894882
E-mail.
support@epsolarpv.com
Website.
www.epsolarpv.com,
www.epever.com
Here is the email I got, and attached pdf file with explanation
Dear Dule,
Thanks for your email.
About your issue, if the solar panels are installed in areas with robust sunlight, it's not suggested to hook oversize PV than the rated power. Under such condition ,the charge controller will be running at full power all the time, which will decrease its lifespan.
The more information, please refer to the instruction in the attachment. Thanks, have a nice day!
Best regards
Bianca
Electrical Enqineer
Looks like they dont recomend using more than 520W even I believe that my plan could work. 4x170W=680W, but we know you never get from the roof more than 75-80% ant thats about 510W-540W
So it's not only amps and volts when you are calculating and selecting equipment. Now, I wish I spent a few hunderd dollars more and got Victron 150/70 for $600. It takes 1000W.
What did I learn here? Even Will said this is his favorite CC, it's still just limited Chinese junk.