I dont really know but I have a 190w 24 volt sola panel with a regulator/controller that reduces the voltage output to 12 volt and it keeps my 12 volt battery in good shape and I havnt seen under 12.3 volts even on cloudy days cheers blaze
The "KEMO" Accu Charging Regulator, I already have installed. It does the job but I can hardly see the glow on the tiny "Amber LED Charging indicator". One of the reasons why my earlier problem (see post "Solar Panel Fault") with the solar panel was not spotted earlier. The green " fully charged" LED indicator glows well on this.
I have trialed the Welsee "Controller", and it works fine as well. Large LED's Displaying, Charging, Battery condition, and Load.