So, just looking around at MPPT charge controllers since they are supposed to be way better than PWM ones.. on amazon a 40A is about $210
http://smile.amazon.com/Renogy%C2%AE-Tracer-Charge-Controller-100VDC/dp/B00E7NI9PE/ref=sr_1_1?ie=UTF8&qid=1435102630&sr=8-1&keywords=MPPT+Charge+Controller
so I go to ebay and find this one..
http://www.ebay.com/itm/Solar-Panel-Regulator-LCD-10-20-30-40A-12V-24V-MPPT-Charge-Controller-3-Timer-KJ-/171557580106?pt=LH_DefaultDomain_0&var=&hash=item27f1a0ed4a
is it total garbage? do I even waste my money on it? Is the one on amazon worth $140 more?