Solar charging voltage, not what you expected August 08, 2014, 10:08:40 pm Yahoo Message Number: 147872Hi Aad. There should be a row of DIP switches accessible on the back of the charge controller. They can be placed in various combinations to adjust the charging voltage. I don't have that type of controller, so my manual wouldn't help any way. If you have the original manual, it should have instructions. RonB