Most panels put out around 17V taking into account loss between the panel and the controller. The controller then takes adjusts the voltage down to the proper charging level. Any drop between the controller and battery ( caused by wire length between them) results in a further drop in charging voltage that impacts charging capability. If you park your TM in the shade and want your panels to be efficient, I suggest portable. A simple inexpensive collapsible support can be built from PVC.
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