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It depends on the voltage your panels are putting out. Natively most panels are ~ 18Vdc. But you can hook them up in series which increases the voltage and allows a smaller gauge wire from the panels to the controller. The controller should be near the batteries and the wire from the controller which will be at 12Vdc nominal should be sized for that run.
On my Foretravel I have 4 of 100 watt panels, 2 pair hooked in series, then 1 set of 10 gauge wires. That gives me ~40Vdc to the controller which is about 2' to the batteries.
But if panels are wired in series you could have a detrimental affect if one of the set in series is shaded.