[jetskier]

Originally Posted by kowbra

Perhaps that is true.
But, I'm not sure I understand... why are you rearranging the equation? I didn't quite follow all of that.

Thanks,

Brad

You rearrange to solve for Iout.
Look at my blue Victron image above. If you multiply the PV voltage * the PV Current, it's the 531W. Now multiply the battery voltage * the battery current. It's slightly less ~ 509W. That's the internal losses in the controller. My controller is around 95-97% efficient. Jaboni's spec sheet states a 97% peak efficiency. So we're in the ballpark.


I think there's confusion on 18V or 24V panels. It really doesn't matter if you understand parallel or series configurations. In series configurations with different input voltages, you need the PV panel specs to have the operating current close (like within 2-5%). If you don't, it will operate at the lowest current for the panel in that string and your not getting the full output capabilities of the panels. For example, my 160W panels have an Imp=8.6A and Vmp=18.6V. The 270W panels have an Imp=8.77A and Vmp=30.80V. Voltages are summed and current is the lowest on the string. That's like 2% difference in current. Perfect for a series configuration. The short circuit current and open circuit voltages should be in the same tolerance as well. They matter for the max input voltage when you're well below the lab testing of 25°C. The reason I went this way was the Jaboni panel that came with the trailer was a 265W, the 270W I found nearly matched. I don't have the room on the roof for the wide panels with the two roof vents and 3rd AC I added. The 160W panels are narrow and fit on the sides around those obstacles.

Parallel is similar, but the voltages need to be close. Currents add.