Originally Posted by Formosa Scott
I am installing three 305 24v panels. The label on the back of the panel reads "Open current
voltage 45.6" and "Max power 36.9" I have read this is normal for 24v panels but how to I apply this to the charge controller? Will a Victron that shows 12V 24V 48V 70A MPPT work? I have read 36v will not work some controllers. The Outback 80a shows 12V 24V 36V 48V 60V
I think you will find the 12V 24V and 48V refers to the battery
voltage not the solar panel voltage, so with a 12v (or 24V) battery
system you should be fine. Be careful to check the max input voltage of the controller. It will be buried in the specs somewhere. If this is exceeded the controller will almost instantly be fried.
If you connect your solar panels
in parallel the maximum open circuit voltage is 45.6V, but in rare cases solar panels
can exceed this voltage so you need a reserve. Most controller manufacturers recommend the maximum input voltage should be at least in the order of 20% greater than the open circuit voltage of the array (so around 55v+ for your panels in parallel). If it is close to this number it is worth checking with the manufacturer.
It would also be worth checking with the manufacturer that the unit self protects if over 70 A are produced. Most, but not all controllers will do this. You will very rarly exceed 70A, but in exceptional circumstances it is possible (assumining you have a 12v battery system)