Bob would like to run his house off the grid, therefore he needs to find out how many solar panels and batteries he needs to buy. the power output of a 250 w solar panel is p=250−10(t−5)2 watts for the average 10 hour day. he plans on using 12 v, 120 a⋅h batteries and would like to able to store 3 days worth of energy. bob's house uses 950 kw⋅h per month (30 days).