Ideally, the device should be set to the Float voltage recommended by the manufacturer of your starter batteries. For most 24v Lead/Calcium batteries, this will be between 27.2 and 27.8 volts.
Like one or two others my panel voltage is two high for direct connection to the unit.
I have two Votronic MPP350 controllers. One of the ancillary connections is a 2amp 12V start battery charge connection. Can I use this connection as the input to the unit. If so are there any other precautions I need to take?