Sounds like the voltage you might get after a long cable run, lots of splices, bad connectors if only one panel were hooked up. Like if you had them all in parallel instead of series. How long of a cable run? All 11 panels in parallel might put out something as pitiful as 12v after a long cable run.
12 and change would also be the voltage the charge controller might be putting out, or the battery voltages.
Also, not having seen the specs on your 11, 100 watt panels.. 11 normal 100 watt panels, wired in series would blow the 150vdc limit on the renogy rover and destroy it.