PWM controllers don't change voltage. They just turn the input and and off very fast to keep a battery from getting charged up too much. MPPT controllers actually convert from one voltage to another with a DC to DC converter circuit.
Solar panels behave very differently than power supplies. You can short out a solar panel and it won't matter. They are a current source, not a voltage source. They will just put out their rated current at whatever voltage they are connected to.
Why purchase a 24v supply and a charge controller for probably about $1,000 when you can buy the proper programmable inverter/charger and get a very nice inverter in the deal?
