Low amp charging from solar panels is typically caused by loose connections, incorrect controller settings, or battery issues rather than a bad controller. Start by checking all wiring connections and battery voltage before replacing the charge controller.
Exterior reflective covers with insulation are most effective for hot window frames. Block sun before it heats aluminum. Attach with suction cups, snaps, or tie-downs. DIY with Reflectix works well. Interior solutions help but exterior blocking is superior.
For three 400W panels (1200W total), you'll need an 80-100 amp MPPT controller. Calculate by dividing total wattage by battery voltage, then add 25% safety margin.
Check LiFePO4 at rest - 13.2-13.4V is full. Clean panels, check all connections for corrosion, verify charge controller is set for lithium. 2150W solar should charge easily if system is working.
Car umbrella canopies can work as temporary RV roof shading, but you'll need to address wind resistance, mounting challenges, and coverage gaps. They're a viable budget alternative to Shade RV products for short-term use.