The most efficient tilt for photovoltaic panels in San Bernardino, California at a latitude of 34.14°:
Your photovoltaic panels need to be angled facing south.
If you're mounting the photovoltaic panels at a stationary angle, such as on your roof, the most efficient angle is 29°.
If you're planning to change the angle of your photovoltaic panels twice per year, the most efficient angle is 10.8° in summer months and 49.1° in winter months.
If you're planning to change the angle of your photovoltaic panels each season, the most efficient angle is 7.1° in summer months and 54.4° in winter months, and 31.2° in autumn and spring months.