FAQ: What is the max solar power for the 10Amp MPPT controller?

Answer: The the power rating for the MPPT controllers is given by the voltage [V] and the current [A]. The max current [A] of the MPPT controller is fixed and cannot be over reached. 

This means the voltage of the batter will determine the power rating. With the “half of the voltage” (12V versus 24V) you get only “half of the maximal power”.

For example: the maximal power is about 240W at 24V:

12V 10A —-> nominal 120W  (up to 140Wp of max panel rating)
24V 10A —-> nominal 240W  (up to 260Wp of max panel rating)

In order to have a 240Wp (250Wp) power rating of the panel, you need to use the 24V battery.  With the 12V battery, the max power is only 120W (up to 140Wp).