[PNW Fireguy]

If your conttroller can handle the voltage of the resultant array you can wire your panels in series to keep the current at or below Isc of the panels. Number 10 wire ampacity ratings are sufficient for this deisgn. If your panels have bypass diodes any panel shading effects will be confined to the shaded panel only. If you solar panels do not have bypass diodes shading can be a much more significant issue to a PV array wired in series.



I would not count on being able to pull new wire to the roof using the original path. Your labor will be minimized and chances of success will be greatly increased by using one of hollow wall voids or tank vents to pull new wire. You should be able to find lots of examples via Google search.


Just a final tip...you may surprised to find that those same 350w panels wired in series and using an MPPT charge controller will out perform the same configuration in parallel all things equal. If you can mount the panels to remove any shading caused by roof mounted equipment the resultant higher voltage of your array will increase your harvesting time significantly. The Victon MPPT will start bulk mode sooner in the AM and charge further into the PM.


I forgot to add don't worry about too many watts for your battery size. Since you are using AGM/FLA your bulk mode charging will be fine it's the absorb mode that will take forever and thats because of the battery type. You will want all the wattage you can get. I am willing to bet that you might go days without getting to float unless you are in a southern lattitude with Aug sun directly overhead and hazing from light clouds.