| David, Welcome to the group. I charge an electric boat I have directly using 4 -75w 12v panels and a Dingo mppt charge controller. Mine is set up for a 48V pack but it will do 36V also. You just wire the panels in series and set the controller for 36V. It can handle up to 100v input so you should be ok but you should check the max open circuit voltage of your panels. I found that with 5- 12Vpanels I was getting a little close to 100V so I stayed with 4 I use agm batteries in my electraks (no cost savings here). For charging those I use a wall mounted charger($350 )set up for agm plugged into the grid . I have gotten used to using the stock speed controls on my e15 and I find them adequate. I do have an old taylor-dunn speed control that I plan to play with someday. Does what you have work? Kimball |