I am going to be using a MPPT 75/10 to charge my custom lithium ion 18650 battery pack. The nominal voltage of the 18650 cells are 3.6V. The 75/10 MPPT is rated for 12/24V batteries. My question is the flexibility of this output battery voltage. Is the 12/24V rating supposed to be the nominal voltage of the battery? Building up an 18650 pack, the nominal voltages could be 21.6V for a 6S pack or 25.2V for a 7S pack. Is the 75/10 MPPT flexible so it could handle this? How much flexibility does it have?