Solar storage requierment - California

How many days/weeks/months of battery storage would you need if 100% of the electricity in California was to be produced by solar PV?

Assumptions:
1. Monthly energy consumption is equal every month
2. No losses when charging/discharging the battery

Imperial Valley Solar - 200MW
2014 - 1,36 months of energy storage required (Cf = 28,57%)
2015 - 1,41 months of energy storage required (Cf = 30,74%)
2016 - 1,51 months of energy storage required (Cf = 30,62%)

California Valley Solar Ranch - 250MW Single axis
2014 - 1,75 months of energy storage
required (Cf = 31,25%)
2015 - 1,51 months of energy storage required (Cf= 31,42%)
2016 - 1,72 months of energy storage required (Cf= 31,04%)

Dessert Sunlight - 300MW Fixed
2014 - 0,79 months of energy storage
required (Cf = 20,83%)
2015 - 0,72 months of energy storage required (Cf = 25,60%)
2016 - 0,79 months of energy storage required (Cf = 27,49%)

Topaz Solar - 550MW Fixed
2014 - 1,64 months of energy storage
required (Cf = 21,86%)
2015 - 0,77 months of energy storage required (Cf = 27,00%)
2016 - 1,10 months of energy storage required (Cf = 26,27%)