adding portable solar panels to existing system and adding batteries

[maxtotow]

Hi all, I am new here, so go easy on me.
I am considering the purchase of an RV with pre-installed solar system. It consist of 3 panels on roof for 640 watts, ( I don't know yet if in series or parallel), this is going into a Renogy 60 amp MPPT controller, charging 3-100 amp Renogy Lithium batteries connected in parallel.
I have some existing solar panels for 400 watts and am considering adding those independent of the panels on the roof as I would use the 400 watts as additional power positioned as needed to maximize the sun angle.
I believe that I would need another MPPT controller to do this. Is that correct? Since the voltages from each bank of panels input would be different.

On another problem.
Could I add a 100 amp Battleborn battery in parallel to the existing 3 Renogy 100 amp batteries? I did some searching on here and it seems as if it is possible.
Thank you

 

[sunshine_eggo]

I believe that I would need another MPPT controller to do this. Is that correct? Since the voltages from each bank of panels input would be different.

Yes for that reason, and because your 640W array is already close to maxing out the 60A controller, 640/12 = 53A.

Could I add a 100 amp Battleborn battery in parallel to the existing 3 Renogy 100 amp batteries? I did some searching on here and it seems as if it is possible.

Yes. Read the Victron Wiring Unlimited document in the Resources section for best practices when paralleling batteries.