Bonnie it is more about which components, i.e. I have a 185W panel on to of the tear wires go from that to the input side of the Morningstar SunSaver and from the output of the SS to the battery. In my case I had to us the MPPT version because I bought a high voltage panel by mistake but the PWM version which is less expensive is a very good simple to set up controller. http://www.morningstarcorp.com/wp-content/uploads/2014/02/SS3.IOM_.Operators_Manual.01.EN_.pdf The battery is the one you have.